source: downloads/tcl8.5.2/generic/tclExecute.c @ 25

/*
 * tclExecute.c --
 *
 *      This file contains procedures that execute byte-compiled Tcl commands.
 *
 * Copyright (c) 1996-1997 Sun Microsystems, Inc.
 * Copyright (c) 1998-2000 by Scriptics Corporation.
 * Copyright (c) 2001 by Kevin B. Kenny. All rights reserved.
 * Copyright (c) 2002-2005 by Miguel Sofer.
 * Copyright (c) 2005-2007 by Donal K. Fellows.
 * Copyright (c) 2007 Daniel A. Steffen <das@users.sourceforge.net>
 *
 * See the file "license.terms" for information on usage and redistribution of
 * this file, and for a DISCLAIMER OF ALL WARRANTIES.
 *
 * RCS: @(#) $Id: tclExecute.c,v 1.369 2008/03/18 18:52:07 msofer Exp $
 */

#include "tclInt.h"
#include "tclCompile.h"
#include "tommath.h"

#include <math.h>
#include <float.h>

/*
 * Hack to determine whether we may expect IEEE floating point. The hack is
 * formally incorrect in that non-IEEE platforms might have the same precision
 * and range, but VAX, IBM, and Cray do not; are there any other floating
 * point units that we might care about?
 */

#if (FLT_RADIX == 2) && (DBL_MANT_DIG == 53) && (DBL_MAX_EXP == 1024)
#define IEEE_FLOATING_POINT
#endif

/*
 * A mask (should be 2**n-1) that is used to work out when the bytecode engine
 * should call Tcl_AsyncReady() to see whether there is a signal that needs
 * handling.
 */

#ifndef ASYNC_CHECK_COUNT_MASK
#   define ASYNC_CHECK_COUNT_MASK       63
#endif /* !ASYNC_CHECK_COUNT_MASK */

/*
 * Boolean flag indicating whether the Tcl bytecode interpreter has been
 * initialized.
 */

static int execInitialized = 0;
TCL_DECLARE_MUTEX(execMutex)

#ifdef TCL_COMPILE_DEBUG
/*
 * Variable that controls whether execution tracing is enabled and, if so,
 * what level of tracing is desired:
 *    0: no execution tracing
 *    1: trace invocations of Tcl procs only
 *    2: trace invocations of all (not compiled away) commands
 *    3: display each instruction executed
 * This variable is linked to the Tcl variable "tcl_traceExec".
 */

int tclTraceExec = 0;
#endif

/*
 * Mapping from expression instruction opcodes to strings; used for error
 * messages. Note that these entries must match the order and number of the
 * expression opcodes (e.g., INST_LOR) in tclCompile.h.
 *
 * Does not include the string for INST_EXPON (and beyond), as that is
 * disjoint for backward-compatability reasons.
 */

static const char *operatorStrings[] = {
    "||", "&&", "|", "^", "&", "==", "!=", "<", ">", "<=", ">=", "<<", ">>",
    "+", "-", "*", "/", "%", "+", "-", "~", "!",
    "BUILTIN FUNCTION", "FUNCTION",
    "", "", "", "", "", "", "", "", "eq", "ne"
};

/*
 * Mapping from Tcl result codes to strings; used for error and debugging
 * messages.
 */

#ifdef TCL_COMPILE_DEBUG
static const char *resultStrings[] = {
    "TCL_OK", "TCL_ERROR", "TCL_RETURN", "TCL_BREAK", "TCL_CONTINUE"
};
#endif

/*
 * These are used by evalstats to monitor object usage in Tcl.
 */

#ifdef TCL_COMPILE_STATS
long            tclObjsAlloced = 0;
long            tclObjsFreed = 0;
long            tclObjsShared[TCL_MAX_SHARED_OBJ_STATS] = { 0, 0, 0, 0, 0 };
#endif /* TCL_COMPILE_STATS */

/*
 * Support pre-8.5 bytecodes unless specifically requested otherwise.
 */

#ifndef TCL_SUPPORT_84_BYTECODE
#define TCL_SUPPORT_84_BYTECODE 1
#endif

#if TCL_SUPPORT_84_BYTECODE
/*
 * We need to know the tclBuiltinFuncTable to support translation of pre-8.5
 * math functions to the namespace-based ::tcl::mathfunc::op in 8.5+.
 */

typedef struct {
    char *name;         /* Name of function. */
    int numArgs;        /* Number of arguments for function. */
} BuiltinFunc;

/*
 * Table describing the built-in math functions. Entries in this table are
 * indexed by the values of the INST_CALL_BUILTIN_FUNC instruction's
 * operand byte.
 */

static BuiltinFunc tclBuiltinFuncTable[] = {
    {"acos", 1},
    {"asin", 1},
    {"atan", 1},
    {"atan2", 2},
    {"ceil", 1},
    {"cos", 1},
    {"cosh", 1},
    {"exp", 1},
    {"floor", 1},
    {"fmod", 2},
    {"hypot", 2},
    {"log", 1},
    {"log10", 1},
    {"pow", 2},
    {"sin", 1},
    {"sinh", 1},
    {"sqrt", 1},
    {"tan", 1},
    {"tanh", 1},
    {"abs", 1},
    {"double", 1},
    {"int", 1},
    {"rand", 0},
    {"round", 1},
    {"srand", 1},
    {"wide", 1},
    {0},
};

#define LAST_BUILTIN_FUNC       25
#endif

/*
 * These variable-access macros have to coincide with those in tclVar.c
 */

#define VarHashGetValue(hPtr) \
    ((Var *) ((char *)hPtr - TclOffset(VarInHash, entry)))

static inline Var *
VarHashCreateVar(
    TclVarHashTable *tablePtr,
    Tcl_Obj *key,
    int *newPtr)
{
    Tcl_HashEntry *hPtr = Tcl_CreateHashEntry((Tcl_HashTable *) tablePtr,
            (char *) key, newPtr);

    if (!hPtr) {
        return NULL;
    }
    return VarHashGetValue(hPtr);
}

#define VarHashFindVar(tablePtr, key) \
    VarHashCreateVar((tablePtr), (key), NULL)

/*
 * The new macro for ending an instruction; note that a reasonable C-optimiser
 * will resolve all branches at compile time. (result) is always a constant;
 * the macro NEXT_INST_F handles constant (nCleanup), NEXT_INST_V is resolved
 * at runtime for variable (nCleanup).
 *
 * ARGUMENTS:
 *    pcAdjustment: how much to increment pc
 *    nCleanup: how many objects to remove from the stack
 *    resultHandling: 0 indicates no object should be pushed on the stack;
 *      otherwise, push objResultPtr. If (result < 0), objResultPtr already
 *      has the correct reference count.
 */

#define NEXT_INST_F(pcAdjustment, nCleanup, resultHandling) \
    if (nCleanup == 0) {\
        if (resultHandling != 0) {\
            if ((resultHandling) > 0) {\
                PUSH_OBJECT(objResultPtr);\
            } else {\
                *(++tosPtr) = objResultPtr;\
            }\
        } \
        pc += (pcAdjustment);\
        goto cleanup0;\
    } else if (resultHandling != 0) {\
        if ((resultHandling) > 0) {\
            Tcl_IncrRefCount(objResultPtr);\
        }\
        pc += (pcAdjustment);\
        switch (nCleanup) {\
            case 1: goto cleanup1_pushObjResultPtr;\
            case 2: goto cleanup2_pushObjResultPtr;\
            default: Tcl_Panic("bad usage of macro NEXT_INST_F");\
        }\
    } else {\
        pc += (pcAdjustment);\
        switch (nCleanup) {\
            case 1: goto cleanup1;\
            case 2: goto cleanup2;\
            default: Tcl_Panic("bad usage of macro NEXT_INST_F");\
        }\
    }

#define NEXT_INST_V(pcAdjustment, nCleanup, resultHandling) \
    pc += (pcAdjustment);\
    cleanup = (nCleanup);\
    if (resultHandling) {\
        if ((resultHandling) > 0) {\
            Tcl_IncrRefCount(objResultPtr);\
        }\
        goto cleanupV_pushObjResultPtr;\
    } else {\
        goto cleanupV;\
    }

/*
 * Macros used to cache often-referenced Tcl evaluation stack information
 * in local variables. Note that a DECACHE_STACK_INFO()-CACHE_STACK_INFO()
 * pair must surround any call inside TclExecuteByteCode (and a few other
 * procedures that use this scheme) that could result in a recursive call
 * to TclExecuteByteCode.
 */

#define CACHE_STACK_INFO() \
    checkInterp = 1

#define DECACHE_STACK_INFO() \
    esPtr->tosPtr = tosPtr

/*
 * Macros used to access items on the Tcl evaluation stack. PUSH_OBJECT
 * increments the object's ref count since it makes the stack have another
 * reference pointing to the object. However, POP_OBJECT does not decrement
 * the ref count. This is because the stack may hold the only reference to the
 * object, so the object would be destroyed if its ref count were decremented
 * before the caller had a chance to, e.g., store it in a variable. It is the
 * caller's responsibility to decrement the ref count when it is finished with
 * an object.
 *
 * WARNING! It is essential that objPtr only appear once in the PUSH_OBJECT
 * macro. The actual parameter might be an expression with side effects, and
 * this ensures that it will be executed only once.
 */

#define PUSH_OBJECT(objPtr) \
    Tcl_IncrRefCount(*(++tosPtr) = (objPtr))

#define POP_OBJECT()    *(tosPtr--)

#define OBJ_AT_TOS      *tosPtr

#define OBJ_UNDER_TOS   *(tosPtr-1)

#define OBJ_AT_DEPTH(n) *(tosPtr-(n))

#define CURR_DEPTH      (tosPtr - initTosPtr)

/*
 * Macros used to trace instruction execution. The macros TRACE,
 * TRACE_WITH_OBJ, and O2S are only used inside TclExecuteByteCode. O2S is
 * only used in TRACE* calls to get a string from an object.
 */

#ifdef TCL_COMPILE_DEBUG
#   define TRACE(a) \
    if (traceInstructions) { \
        fprintf(stdout, "%2d: %2d (%u) %s ", iPtr->numLevels, \
                (int) CURR_DEPTH, \
                (unsigned)(pc - codePtr->codeStart), \
                GetOpcodeName(pc)); \
        printf a; \
    }
#   define TRACE_APPEND(a) \
    if (traceInstructions) { \
        printf a; \
    }
#   define TRACE_WITH_OBJ(a, objPtr) \
    if (traceInstructions) { \
        fprintf(stdout, "%2d: %2d (%u) %s ", iPtr->numLevels, \
                (int) CURR_DEPTH, \
                (unsigned)(pc - codePtr->codeStart), \
                GetOpcodeName(pc)); \
        printf a; \
        TclPrintObject(stdout, objPtr, 30); \
        fprintf(stdout, "\n"); \
    }
#   define O2S(objPtr) \
    (objPtr ? TclGetString(objPtr) : "")
#else /* !TCL_COMPILE_DEBUG */
#   define TRACE(a)
#   define TRACE_APPEND(a)
#   define TRACE_WITH_OBJ(a, objPtr)
#   define O2S(objPtr)
#endif /* TCL_COMPILE_DEBUG */

/*
 * DTrace instruction probe macros.
 */

#define TCL_DTRACE_INST_NEXT() \
    if (TCL_DTRACE_INST_DONE_ENABLED()) {\
        if (curInstName) {\
            TCL_DTRACE_INST_DONE(curInstName, (int) CURR_DEPTH, tosPtr);\
        }\
        curInstName = tclInstructionTable[*pc].name;\
        if (TCL_DTRACE_INST_START_ENABLED()) {\
            TCL_DTRACE_INST_START(curInstName, (int) CURR_DEPTH, tosPtr);\
        }\
    } else if (TCL_DTRACE_INST_START_ENABLED()) {\
        TCL_DTRACE_INST_START(tclInstructionTable[*pc].name, (int) CURR_DEPTH,\
                tosPtr);\
    }
#define TCL_DTRACE_INST_LAST() \
    if (TCL_DTRACE_INST_DONE_ENABLED() && curInstName) {\
        TCL_DTRACE_INST_DONE(curInstName, (int) CURR_DEPTH, tosPtr);\
    }

/*
 * Macro used in this file to save a function call for common uses of
 * TclGetNumberFromObj(). The ANSI C "prototype" is:
 *
 * MODULE_SCOPE int GetNumberFromObj(Tcl_Interp *interp, Tcl_Obj *objPtr,
 *                      ClientData *ptrPtr, int *tPtr);
 */

#ifdef NO_WIDE_TYPE

#define GetNumberFromObj(interp, objPtr, ptrPtr, tPtr)                  \
    (((objPtr)->typePtr == &tclIntType)                                 \
        ?       (*(tPtr) = TCL_NUMBER_LONG,                             \
                *(ptrPtr) = (ClientData)                                \
                    (&((objPtr)->internalRep.longValue)), TCL_OK) :     \
    ((objPtr)->typePtr == &tclDoubleType)                               \
        ?       (((TclIsNaN((objPtr)->internalRep.doubleValue))         \
                    ?   (*(tPtr) = TCL_NUMBER_NAN)                      \
                    :   (*(tPtr) = TCL_NUMBER_DOUBLE)),                 \
                *(ptrPtr) = (ClientData)                                \
                    (&((objPtr)->internalRep.doubleValue)), TCL_OK) :   \
    ((((objPtr)->typePtr == NULL) && ((objPtr)->bytes == NULL)) ||      \
    (((objPtr)->bytes != NULL) && ((objPtr)->length == 0)))             \
        ? TCL_ERROR :                                                   \
    TclGetNumberFromObj((interp), (objPtr), (ptrPtr), (tPtr)))

#else

#define GetNumberFromObj(interp, objPtr, ptrPtr, tPtr)                  \
    (((objPtr)->typePtr == &tclIntType)                                 \
        ?       (*(tPtr) = TCL_NUMBER_LONG,                             \
                *(ptrPtr) = (ClientData)                                \
                    (&((objPtr)->internalRep.longValue)), TCL_OK) :     \
    ((objPtr)->typePtr == &tclWideIntType)                              \
        ?       (*(tPtr) = TCL_NUMBER_WIDE,                             \
                *(ptrPtr) = (ClientData)                                \
                    (&((objPtr)->internalRep.wideValue)), TCL_OK) :     \
    ((objPtr)->typePtr == &tclDoubleType)                               \
        ?       (((TclIsNaN((objPtr)->internalRep.doubleValue))         \
                    ?   (*(tPtr) = TCL_NUMBER_NAN)                      \
                    :   (*(tPtr) = TCL_NUMBER_DOUBLE)),                 \
                *(ptrPtr) = (ClientData)                                \
                    (&((objPtr)->internalRep.doubleValue)), TCL_OK) :   \
    ((((objPtr)->typePtr == NULL) && ((objPtr)->bytes == NULL)) ||      \
    (((objPtr)->bytes != NULL) && ((objPtr)->length == 0)))             \
        ? TCL_ERROR :                                                   \
    TclGetNumberFromObj((interp), (objPtr), (ptrPtr), (tPtr)))

#endif

/*
 * Macro used in this file to save a function call for common uses of
 * Tcl_GetBooleanFromObj(). The ANSI C "prototype" is:
 *
 * MODULE_SCOPE int TclGetBooleanFromObj(Tcl_Interp *interp, Tcl_Obj *objPtr,
 *                      int *boolPtr);
 */

#define TclGetBooleanFromObj(interp, objPtr, boolPtr)                   \
    ((((objPtr)->typePtr == &tclIntType)                                \
        || ((objPtr)->typePtr == &tclBooleanType))                      \
        ? (*(boolPtr) = ((objPtr)->internalRep.longValue!=0), TCL_OK)   \
        : Tcl_GetBooleanFromObj((interp), (objPtr), (boolPtr)))

/*
 * Macro used in this file to save a function call for common uses of
 * Tcl_GetWideIntFromObj(). The ANSI C "prototype" is:
 *
 * MODULE_SCOPE int TclGetWideIntFromObj(Tcl_Interp *interp, Tcl_Obj *objPtr,
 *                      Tcl_WideInt *wideIntPtr);
 */

#ifdef NO_WIDE_TYPE
#define TclGetWideIntFromObj(interp, objPtr, wideIntPtr)                \
    (((objPtr)->typePtr == &tclIntType)                                 \
        ? (*(wideIntPtr) = (Tcl_WideInt)                                \
                ((objPtr)->internalRep.longValue), TCL_OK) :            \
        Tcl_GetWideIntFromObj((interp), (objPtr), (wideIntPtr)))
#else
#define TclGetWideIntFromObj(interp, objPtr, wideIntPtr)                \
    (((objPtr)->typePtr == &tclWideIntType)                             \
        ? (*(wideIntPtr) = (objPtr)->internalRep.wideValue, TCL_OK) :   \
    ((objPtr)->typePtr == &tclIntType)                                  \
        ? (*(wideIntPtr) = (Tcl_WideInt)                                \
                ((objPtr)->internalRep.longValue), TCL_OK) :            \
        Tcl_GetWideIntFromObj((interp), (objPtr), (wideIntPtr)))
#endif

/*
 * Macro used to make the check for type overflow more mnemonic. This works by
 * comparing sign bits; the rest of the word is irrelevant. The ANSI C
 * "prototype" (where inttype_t is any integer type) is:
 *
 * MODULE_SCOPE int Overflowing(inttype_t a, inttype_t b, inttype_t sum);
 *
 * Check first the condition most likely to fail in usual code (at least for
 * usage in [incr]: do the first summand and the sum have != signs?
 */

#define Overflowing(a,b,sum) ((((a)^(sum)) < 0) && (((a)^(b)) >= 0))

/*
 * Custom object type only used in this file; values of its type should never
 * be seen by user scripts.
 */

static Tcl_ObjType dictIteratorType = {
    "dictIterator",
    NULL, NULL, NULL, NULL
};

/*
 * Auxiliary tables used to compute powers of small integers
 */

#if (LONG_MAX == 0x7fffffff)

/*
 * Maximum base that, when raised to powers 2, 3, ... 8, fits in a 32-bit
 * signed integer
 */

static const long MaxBase32[7] = {46340, 1290, 215, 73, 35, 21, 14};

/*
 * Table giving 3, 4, ..., 11, raised to the powers 9, 10, ..., as far as they
 * fit in a 32-bit signed integer. Exp32Index[i] gives the starting index of
 * powers of i+3; Exp32Value[i] gives the corresponding powers.
 */

static const unsigned short Exp32Index[] = {
    0, 11, 18, 23, 26, 29, 31, 32, 33
};
static const long Exp32Value[] = {
    19683, 59049, 177147, 531441, 1594323, 4782969, 14348907, 43046721,
    129140163, 387420489, 1162261467, 262144, 1048576, 4194304,
    16777216, 67108864, 268435456, 1073741824, 1953125, 9765625,
    48828125, 244140625, 1220703125, 10077696, 60466176, 362797056,
    40353607, 282475249, 1977326743, 134217728, 1073741824, 387420489,
    1000000000
};

#endif /* LONG_MAX == 0x7fffffff -- 32 bit machine */

#if (LONG_MAX > 0x7fffffff) || !defined(TCL_WIDE_INT_IS_LONG)

/*
 * Maximum base that, when raised to powers 2, 3, ..., 16, fits in a
 * Tcl_WideInt.
 */

static Tcl_WideInt MaxBaseWide[15];

/*
 *Table giving 3, 4, ..., 13 raised to powers greater than 16 when the
 * results fit in a 64-bit signed integer.
 */

static const unsigned short Exp64Index[] = {
    0, 23, 38, 49, 57, 63, 67, 70, 72, 74, 75, 76
};
static const Tcl_WideInt Exp64Value[] = {
    (Tcl_WideInt)243*243*243*3*3,
    (Tcl_WideInt)243*243*243*3*3*3,
    (Tcl_WideInt)243*243*243*3*3*3*3,
    (Tcl_WideInt)243*243*243*243,
    (Tcl_WideInt)243*243*243*243*3,
    (Tcl_WideInt)243*243*243*243*3*3,
    (Tcl_WideInt)243*243*243*243*3*3*3,
    (Tcl_WideInt)243*243*243*243*3*3*3*3,
    (Tcl_WideInt)243*243*243*243*243,
    (Tcl_WideInt)243*243*243*243*243*3,
    (Tcl_WideInt)243*243*243*243*243*3*3,
    (Tcl_WideInt)243*243*243*243*243*3*3*3,
    (Tcl_WideInt)243*243*243*243*243*3*3*3*3,
    (Tcl_WideInt)243*243*243*243*243*243,
    (Tcl_WideInt)243*243*243*243*243*243*3,
    (Tcl_WideInt)243*243*243*243*243*243*3*3,
    (Tcl_WideInt)243*243*243*243*243*243*3*3*3,
    (Tcl_WideInt)243*243*243*243*243*243*3*3*3*3,
    (Tcl_WideInt)243*243*243*243*243*243*243,
    (Tcl_WideInt)243*243*243*243*243*243*243*3,
    (Tcl_WideInt)243*243*243*243*243*243*243*3*3,
    (Tcl_WideInt)243*243*243*243*243*243*243*3*3*3,
    (Tcl_WideInt)243*243*243*243*243*243*243*3*3*3*3,
    (Tcl_WideInt)1024*1024*1024*4*4,
    (Tcl_WideInt)1024*1024*1024*4*4*4,
    (Tcl_WideInt)1024*1024*1024*4*4*4*4,
    (Tcl_WideInt)1024*1024*1024*1024,
    (Tcl_WideInt)1024*1024*1024*1024*4,
    (Tcl_WideInt)1024*1024*1024*1024*4*4,
    (Tcl_WideInt)1024*1024*1024*1024*4*4*4,
    (Tcl_WideInt)1024*1024*1024*1024*4*4*4*4,
    (Tcl_WideInt)1024*1024*1024*1024*1024,
    (Tcl_WideInt)1024*1024*1024*1024*1024*4,
    (Tcl_WideInt)1024*1024*1024*1024*1024*4*4,
    (Tcl_WideInt)1024*1024*1024*1024*1024*4*4*4,
    (Tcl_WideInt)1024*1024*1024*1024*1024*4*4*4*4,
    (Tcl_WideInt)1024*1024*1024*1024*1024*1024,
    (Tcl_WideInt)1024*1024*1024*1024*1024*1024*4,
    (Tcl_WideInt)3125*3125*3125*5*5,
    (Tcl_WideInt)3125*3125*3125*5*5*5,
    (Tcl_WideInt)3125*3125*3125*5*5*5*5,
    (Tcl_WideInt)3125*3125*3125*3125,
    (Tcl_WideInt)3125*3125*3125*3125*5,
    (Tcl_WideInt)3125*3125*3125*3125*5*5,
    (Tcl_WideInt)3125*3125*3125*3125*5*5*5,
    (Tcl_WideInt)3125*3125*3125*3125*5*5*5*5,
    (Tcl_WideInt)3125*3125*3125*3125*3125,
    (Tcl_WideInt)3125*3125*3125*3125*3125*5,
    (Tcl_WideInt)3125*3125*3125*3125*3125*5*5,
    (Tcl_WideInt)7776*7776*7776*6*6,
    (Tcl_WideInt)7776*7776*7776*6*6*6,
    (Tcl_WideInt)7776*7776*7776*6*6*6*6,
    (Tcl_WideInt)7776*7776*7776*7776,
    (Tcl_WideInt)7776*7776*7776*7776*6,
    (Tcl_WideInt)7776*7776*7776*7776*6*6,
    (Tcl_WideInt)7776*7776*7776*7776*6*6*6,
    (Tcl_WideInt)7776*7776*7776*7776*6*6*6*6,
    (Tcl_WideInt)16807*16807*16807*7*7,
    (Tcl_WideInt)16807*16807*16807*7*7*7,
    (Tcl_WideInt)16807*16807*16807*7*7*7*7,
    (Tcl_WideInt)16807*16807*16807*16807,
    (Tcl_WideInt)16807*16807*16807*16807*7,
    (Tcl_WideInt)16807*16807*16807*16807*7*7,
    (Tcl_WideInt)32768*32768*32768*8*8,
    (Tcl_WideInt)32768*32768*32768*8*8*8,
    (Tcl_WideInt)32768*32768*32768*8*8*8*8,
    (Tcl_WideInt)32768*32768*32768*32768,
    (Tcl_WideInt)59049*59049*59049*9*9,
    (Tcl_WideInt)59049*59049*59049*9*9*9,
    (Tcl_WideInt)59049*59049*59049*9*9*9*9,
    (Tcl_WideInt)100000*100000*100000*10*10,
    (Tcl_WideInt)100000*100000*100000*10*10*10,
    (Tcl_WideInt)161051*161051*161051*11*11,
    (Tcl_WideInt)161051*161051*161051*11*11*11,
    (Tcl_WideInt)248832*248832*248832*12*12,
    (Tcl_WideInt)371293*371293*371293*13*13
};

#endif

/*
 * Declarations for local procedures to this file:
 */

#ifdef TCL_COMPILE_STATS
static int              EvalStatsCmd(ClientData clientData,
                            Tcl_Interp *interp, int objc,
                            Tcl_Obj *const objv[]);
#endif /* TCL_COMPILE_STATS */
#ifdef TCL_COMPILE_DEBUG
static char *           GetOpcodeName(unsigned char *pc);
static void             PrintByteCodeInfo(ByteCode *codePtr);
static const char *     StringForResultCode(int result);
static void             ValidatePcAndStackTop(ByteCode *codePtr,
                            unsigned char *pc, int stackTop,
                            int stackLowerBound, int checkStack);
#endif /* TCL_COMPILE_DEBUG */
static void             DeleteExecStack(ExecStack *esPtr);
static void             DupExprCodeInternalRep(Tcl_Obj *srcPtr,
                            Tcl_Obj *copyPtr);
static void             FreeExprCodeInternalRep(Tcl_Obj *objPtr);
static ExceptionRange * GetExceptRangeForPc(unsigned char *pc, int catchOnly,
                            ByteCode *codePtr);
static const char *     GetSrcInfoForPc(unsigned char *pc, ByteCode *codePtr,
                            int *lengthPtr);
static Tcl_Obj **       GrowEvaluationStack(ExecEnv *eePtr, int growth,
                            int move);
static void             IllegalExprOperandType(Tcl_Interp *interp,
                            unsigned char *pc, Tcl_Obj *opndPtr);
static void             InitByteCodeExecution(Tcl_Interp *interp);
/* Useful elsewhere, make available in tclInt.h or stubs? */
static Tcl_Obj **       StackAllocWords(Tcl_Interp *interp, int numWords);
static Tcl_Obj **       StackReallocWords(Tcl_Interp *interp, int numWords);

/*
 * The structure below defines a bytecode Tcl object type to hold the
 * compiled bytecode for Tcl expressions.
 */

static Tcl_ObjType exprCodeType = {
    "exprcode",
    FreeExprCodeInternalRep,    /* freeIntRepProc */
    DupExprCodeInternalRep,     /* dupIntRepProc */
    NULL,                       /* updateStringProc */
    NULL                        /* setFromAnyProc */
};

/*
 *----------------------------------------------------------------------
 *
 * InitByteCodeExecution --
 *
 *      This procedure is called once to initialize the Tcl bytecode
 *      interpreter.
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      This procedure initializes the array of instruction names. If
 *      compiling with the TCL_COMPILE_STATS flag, it initializes the array
 *      that counts the executions of each instruction and it creates the
 *      "evalstats" command. It also establishes the link between the Tcl
 *      "tcl_traceExec" and C "tclTraceExec" variables.
 *
 *----------------------------------------------------------------------
 */

static void
InitByteCodeExecution(
    Tcl_Interp *interp)         /* Interpreter for which the Tcl variable
                                 * "tcl_traceExec" is linked to control
                                 * instruction tracing. */
{
#if (LONG_MAX > 0x7fffffff) || !defined(TCL_WIDE_INT_IS_LONG)
    int i, j;
    Tcl_WideInt w, x;
#endif
#ifdef TCL_COMPILE_DEBUG
    if (Tcl_LinkVar(interp, "tcl_traceExec", (char *) &tclTraceExec,
            TCL_LINK_INT) != TCL_OK) {
        Tcl_Panic("InitByteCodeExecution: can't create link for tcl_traceExec variable");
    }
#endif
#ifdef TCL_COMPILE_STATS
    Tcl_CreateObjCommand(interp, "evalstats", EvalStatsCmd, NULL, NULL);
#endif /* TCL_COMPILE_STATS */
#if (LONG_MAX > 0x7fffffff) || !defined(TCL_WIDE_INT_IS_LONG)

    /*
     * Fill in a table of what base can be raised to powers 2, 3, ... 16
     * without overflowing a Tcl_WideInt
     */

    for (i = 2; i <= 16; ++i) {
        /*
         * Compute an initial guess in floating point.
         */

        w = (Tcl_WideInt) pow((double) LLONG_MAX, 1.0 / i) + 1;

        /*
         * Correct the guess if it's too high.
         */

        for (;;) {
            x = LLONG_MAX;
            for (j = 0; j < i; ++j) {
                x /= w;
            }
            if (x == 1) {
                break;
            }
            --w;
        }

        MaxBaseWide[i-2] = w;
    }
#endif
}

/*
 *----------------------------------------------------------------------
 *
 * TclCreateExecEnv --
 *
 *      This procedure creates a new execution environment for Tcl bytecode
 *      execution. An ExecEnv points to a Tcl evaluation stack. An ExecEnv is
 *      typically created once for each Tcl interpreter (Interp structure) and
 *      recursively passed to TclExecuteByteCode to execute ByteCode sequences
 *      for nested commands.
 *
 * Results:
 *      A newly allocated ExecEnv is returned. This points to an empty
 *      evaluation stack of the standard initial size.
 *
 * Side effects:
 *      The bytecode interpreter is also initialized here, as this procedure
 *      will be called before any call to TclExecuteByteCode.
 *
 *----------------------------------------------------------------------
 */

#define TCL_STACK_INITIAL_SIZE 2000

ExecEnv *
TclCreateExecEnv(
    Tcl_Interp *interp)         /* Interpreter for which the execution
                                 * environment is being created. */
{
    ExecEnv *eePtr = (ExecEnv *) ckalloc(sizeof(ExecEnv));
    ExecStack *esPtr = (ExecStack *) ckalloc(sizeof(ExecStack)
            + (size_t) (TCL_STACK_INITIAL_SIZE-1) * sizeof(Tcl_Obj *));

    eePtr->execStackPtr = esPtr;
    TclNewBooleanObj(eePtr->constants[0], 0);
    Tcl_IncrRefCount(eePtr->constants[0]);
    TclNewBooleanObj(eePtr->constants[1], 1);
    Tcl_IncrRefCount(eePtr->constants[1]);

    esPtr->prevPtr = NULL;
    esPtr->nextPtr = NULL;
    esPtr->markerPtr = NULL;
    esPtr->endPtr = &esPtr->stackWords[TCL_STACK_INITIAL_SIZE-1];
    esPtr->tosPtr = &esPtr->stackWords[-1];

    Tcl_MutexLock(&execMutex);
    if (!execInitialized) {
        TclInitAuxDataTypeTable();
        InitByteCodeExecution(interp);
        execInitialized = 1;
    }
    Tcl_MutexUnlock(&execMutex);

    return eePtr;
}
#undef TCL_STACK_INITIAL_SIZE

/*
 *----------------------------------------------------------------------
 *
 * TclDeleteExecEnv --
 *
 *      Frees the storage for an ExecEnv.
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      Storage for an ExecEnv and its contained storage (e.g. the evaluation
 *      stack) is freed.
 *
 *----------------------------------------------------------------------
 */

static void
DeleteExecStack(
    ExecStack *esPtr)
{
    if (esPtr->markerPtr) {
        Tcl_Panic("freeing an execStack which is still in use");
    }

    if (esPtr->prevPtr) {
        esPtr->prevPtr->nextPtr = esPtr->nextPtr;
    }
    if (esPtr->nextPtr) {
        esPtr->nextPtr->prevPtr = esPtr->prevPtr;
    }
    ckfree((char *) esPtr);
}

void
TclDeleteExecEnv(
    ExecEnv *eePtr)             /* Execution environment to free. */
{
    ExecStack *esPtr = eePtr->execStackPtr, *tmpPtr;

    /*
     * Delete all stacks in this exec env.
     */

    while (esPtr->nextPtr) {
        esPtr = esPtr->nextPtr;
    }
    while (esPtr) {
        tmpPtr = esPtr;
        esPtr = tmpPtr->prevPtr;
        DeleteExecStack(tmpPtr);
    }

    TclDecrRefCount(eePtr->constants[0]);
    TclDecrRefCount(eePtr->constants[1]);
    ckfree((char *) eePtr);
}

/*
 *----------------------------------------------------------------------
 *
 * TclFinalizeExecution --
 *
 *      Finalizes the execution environment setup so that it can be later
 *      reinitialized.
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      After this call, the next time TclCreateExecEnv will be called it will
 *      call InitByteCodeExecution.
 *
 *----------------------------------------------------------------------
 */

void
TclFinalizeExecution(void)
{
    Tcl_MutexLock(&execMutex);
    execInitialized = 0;
    Tcl_MutexUnlock(&execMutex);
    TclFinalizeAuxDataTypeTable();
}

/*
 * Auxiliary code to insure that GrowEvaluationStack always returns correctly 
 * aligned memory. This assumes that TCL_ALLOCALIGN is a multiple of the
 * wordsize 'sizeof(Tcl_Obj *)'. 
 */

#define WALLOCALIGN \
    (TCL_ALLOCALIGN/sizeof(Tcl_Obj *))

static inline int
OFFSET(
    void *ptr)
{
    int mask = TCL_ALLOCALIGN-1;
    int base = PTR2INT(ptr) & mask;
    return (TCL_ALLOCALIGN - base)/sizeof(Tcl_Obj**);
}

#define MEMSTART(markerPtr) \
    ((markerPtr) + OFFSET(markerPtr))


/*
 *----------------------------------------------------------------------
 *
 * GrowEvaluationStack --
 *
 *      This procedure grows a Tcl evaluation stack stored in an ExecEnv,
 *      copying over the words since the last mark if so requested. A mark is
 *      set at the beginning of the new area when no copying is requested.
 *
 * Results:
 *      Returns a pointer to the first usable word in the (possibly) grown
 *      stack.
 *
 * Side effects:
 *      The size of the evaluation stack may be grown, a marker is set
 *
 *----------------------------------------------------------------------
 */

static Tcl_Obj **
GrowEvaluationStack(
    ExecEnv *eePtr,             /* Points to the ExecEnv with an evaluation
                                 * stack to enlarge. */
    int growth,                 /* How much larger than the current used
                                 * size. */
    int move)                   /* 1 if move words since last marker. */
{
    ExecStack *esPtr = eePtr->execStackPtr, *oldPtr = NULL;
    int newBytes, newElems, currElems;
    int needed = growth - (esPtr->endPtr - esPtr->tosPtr);
    Tcl_Obj **markerPtr = esPtr->markerPtr, **memStart;

    if (move) {
        if (!markerPtr) {
            Tcl_Panic("STACK: Reallocating with no previous alloc");
        }
        if (needed <= 0) {
            return MEMSTART(markerPtr);
        }
    } else {
        Tcl_Obj **tmpMarkerPtr = esPtr->tosPtr + 1;
        int offset = OFFSET(tmpMarkerPtr);

        if (needed + offset < 0) {
            /*
             * Put a marker pointing to the previous marker in this stack, and 
             * store it in esPtr as the current marker. Return a pointer to
             * the start of aligned memory.
             */

            esPtr->markerPtr = tmpMarkerPtr;
            memStart = tmpMarkerPtr + offset; 
            esPtr->tosPtr = memStart - 1;
            *esPtr->markerPtr = (Tcl_Obj *) markerPtr;
            return memStart;
        }
    }

    /*
     * Reset move to hold the number of words to be moved to new stack (if
     * any) and growth to hold the complete stack requirements: add the marker
     * and maximal possible offset. 
     */

    if (move) {
        move = esPtr->tosPtr - MEMSTART(markerPtr) + 1;
    }
    needed = growth + move + WALLOCALIGN - 1;

    /*
     * Check if there is enough room in the next stack (if there is one, it
     * should be both empty and the last one!)
     */

    if (esPtr->nextPtr) {
        oldPtr = esPtr;
        esPtr = oldPtr->nextPtr;
        currElems = esPtr->endPtr - &esPtr->stackWords[-1];
        if (esPtr->markerPtr || (esPtr->tosPtr != &esPtr->stackWords[-1])) {
            Tcl_Panic("STACK: Stack after current is in use");
        }
        if (esPtr->nextPtr) {
            Tcl_Panic("STACK: Stack after current is not last");
        }
        if (needed <= currElems) {
            goto newStackReady;
        }
        DeleteExecStack(esPtr);
        esPtr = oldPtr;
    } else {
        currElems = esPtr->endPtr - &esPtr->stackWords[-1];
    }

    /*
     * We need to allocate a new stack! It needs to store 'growth' words,
     * including the elements to be copied over and the new marker.
     */

    newElems = 2*currElems;
    while (needed > newElems) {
        newElems *= 2;
    }
    newBytes = sizeof (ExecStack) + (newElems-1) * sizeof(Tcl_Obj *);

    oldPtr = esPtr;
    esPtr = (ExecStack *) ckalloc(newBytes);

    oldPtr->nextPtr = esPtr;
    esPtr->prevPtr = oldPtr;
    esPtr->nextPtr = NULL;
    esPtr->endPtr = &esPtr->stackWords[newElems-1];

  newStackReady:
    eePtr->execStackPtr = esPtr;

    /*
     * Store a NULL marker at the beginning of the stack, to indicate that
     * this is the first marker in this stack and that rewinding to here
     * should actually be a return to the previous stack.
     */

    esPtr->stackWords[0] = NULL;
    esPtr->markerPtr = &esPtr->stackWords[0];
    memStart = MEMSTART(esPtr->markerPtr);
    esPtr->tosPtr = memStart - 1;
    
    if (move) {
        memcpy(memStart, MEMSTART(markerPtr), move*sizeof(Tcl_Obj *));
        esPtr->tosPtr += move;
        oldPtr->markerPtr = (Tcl_Obj **) *markerPtr;
        oldPtr->tosPtr = markerPtr-1;
    }

    /*
     * Free the old stack if it is now unused.
     */

    if (!oldPtr->markerPtr) {
        DeleteExecStack(oldPtr);
    }

    return memStart;
}

/*
 *--------------------------------------------------------------
 *
 * TclStackAlloc, TclStackRealloc, TclStackFree --
 *
 *      Allocate memory from the execution stack; it has to be returned later
 *      with a call to TclStackFree.
 *
 * Results:
 *      A pointer to the first byte allocated, or panics if the allocation did
 *      not succeed.
 *
 * Side effects:
 *      The execution stack may be grown.
 *
 *--------------------------------------------------------------
 */

static Tcl_Obj **
StackAllocWords(
    Tcl_Interp *interp,
    int numWords)
{
    /*
     * Note that GrowEvaluationStack sets a marker in the stack. This marker
     * is read when rewinding, e.g., by TclStackFree.
     */

    Interp *iPtr = (Interp *) interp;
    ExecEnv *eePtr = iPtr->execEnvPtr;
    Tcl_Obj **resPtr = GrowEvaluationStack(eePtr, numWords, 0);

    eePtr->execStackPtr->tosPtr += numWords;
    return resPtr;
}

static Tcl_Obj **
StackReallocWords(
    Tcl_Interp *interp,
    int numWords)
{
    Interp *iPtr = (Interp *) interp;
    ExecEnv *eePtr = iPtr->execEnvPtr;
    Tcl_Obj **resPtr = GrowEvaluationStack(eePtr, numWords, 1);

    eePtr->execStackPtr->tosPtr += numWords;
    return resPtr;
}

void
TclStackFree(
    Tcl_Interp *interp,
    void *freePtr)
{
    Interp *iPtr = (Interp *) interp;
    ExecEnv *eePtr;
    ExecStack *esPtr;
    Tcl_Obj **markerPtr;

    if (iPtr == NULL || iPtr->execEnvPtr == NULL) {
        Tcl_Free((char *) freePtr);
        return;
    }

    /*
     * Rewind the stack to the previous marker position. The current marker,
     * as set in the last call to GrowEvaluationStack, contains a pointer to
     * the previous marker.
     */

    eePtr = iPtr->execEnvPtr;
    esPtr = eePtr->execStackPtr;
    markerPtr = esPtr->markerPtr;

    if (MEMSTART(markerPtr) != (Tcl_Obj **)freePtr) {
        Tcl_Panic("TclStackFree: incorrect freePtr. Call out of sequence?");
    }

    esPtr->tosPtr = markerPtr-1;
    esPtr->markerPtr = (Tcl_Obj **) *markerPtr;
    if (*markerPtr) {
        return;
    }

    /*
     * Return to previous stack.
     */

    esPtr->tosPtr = &esPtr->stackWords[-1];
    if (esPtr->prevPtr) {
        eePtr->execStackPtr = esPtr->prevPtr;
    }
    if (esPtr->nextPtr) {
        if (!esPtr->prevPtr) {
            eePtr->execStackPtr = esPtr->nextPtr;
        }
        DeleteExecStack(esPtr);
    }
}

void *
TclStackAlloc(
    Tcl_Interp *interp,
    int numBytes)
{
    Interp *iPtr = (Interp *) interp;
    int numWords = (numBytes + (sizeof(Tcl_Obj *) - 1))/sizeof(Tcl_Obj *);

    if (iPtr == NULL || iPtr->execEnvPtr == NULL) {
        return (void *) Tcl_Alloc(numBytes);
    }

    return (void *) StackAllocWords(interp, numWords);
}

void *
TclStackRealloc(
    Tcl_Interp *interp,
    void *ptr,
    int numBytes)
{
    Interp *iPtr = (Interp *) interp;
    ExecEnv *eePtr;
    ExecStack *esPtr;
    Tcl_Obj **markerPtr;
    int numWords;

    if (iPtr == NULL || iPtr->execEnvPtr == NULL) {
        return (void *) Tcl_Realloc((char *) ptr, numBytes);
    }

    eePtr = iPtr->execEnvPtr;
    esPtr = eePtr->execStackPtr;
    markerPtr = esPtr->markerPtr;

    if (MEMSTART(markerPtr) != (Tcl_Obj **)ptr) {
        Tcl_Panic("TclStackRealloc: incorrect ptr. Call out of sequence?");
    }

    numWords = (numBytes + (sizeof(Tcl_Obj *) - 1))/sizeof(Tcl_Obj *);
    return (void *) StackReallocWords(interp, numWords);
}

/*
 *--------------------------------------------------------------
 *
 * Tcl_ExprObj --
 *
 *      Evaluate an expression in a Tcl_Obj.
 *
 * Results:
 *      A standard Tcl object result. If the result is other than TCL_OK, then
 *      the interpreter's result contains an error message. If the result is
 *      TCL_OK, then a pointer to the expression's result value object is
 *      stored in resultPtrPtr. In that case, the object's ref count is
 *      incremented to reflect the reference returned to the caller; the
 *      caller is then responsible for the resulting object and must, for
 *      example, decrement the ref count when it is finished with the object.
 *
 * Side effects:
 *      Any side effects caused by subcommands in the expression, if any. The
 *      interpreter result is not modified unless there is an error.
 *
 *--------------------------------------------------------------
 */

int
Tcl_ExprObj(
    Tcl_Interp *interp,         /* Context in which to evaluate the
                                 * expression. */
    register Tcl_Obj *objPtr,   /* Points to Tcl object containing expression
                                 * to evaluate. */
    Tcl_Obj **resultPtrPtr)     /* Where the Tcl_Obj* that is the expression
                                 * result is stored if no errors occur. */
{
    Interp *iPtr = (Interp *) interp;
    CompileEnv compEnv;         /* Compilation environment structure allocated
                                 * in frame. */
    register ByteCode *codePtr = NULL;
                                /* Tcl Internal type of bytecode. Initialized
                                 * to avoid compiler warning. */
    int result;

    /*
     * Execute the expression after first saving the interpreter's result.
     */

    Tcl_Obj *saveObjPtr = Tcl_GetObjResult(interp);
    Tcl_IncrRefCount(saveObjPtr);

    /*
     * Get the expression ByteCode from the object. If it exists, make sure it
     * is valid in the current context.
     */
    if (objPtr->typePtr == &exprCodeType) {
        Namespace *namespacePtr = iPtr->varFramePtr->nsPtr;

        codePtr = (ByteCode *) objPtr->internalRep.otherValuePtr;
        if (((Interp *) *codePtr->interpHandle != iPtr)
                || (codePtr->compileEpoch != iPtr->compileEpoch)
                || (codePtr->nsPtr != namespacePtr)
                || (codePtr->nsEpoch != namespacePtr->resolverEpoch)) {
            objPtr->typePtr->freeIntRepProc(objPtr);
            objPtr->typePtr = (Tcl_ObjType *) NULL;
        }
    }
    if (objPtr->typePtr != &exprCodeType) {
        /*
         * TIP #280: No invoker (yet) - Expression compilation.
         */

        int length;
        const char *string = TclGetStringFromObj(objPtr, &length);

        TclInitCompileEnv(interp, &compEnv, string, length, NULL, 0);
        TclCompileExpr(interp, string, length, &compEnv, 0);

        /*
         * Successful compilation. If the expression yielded no instructions,
         * push an zero object as the expression's result.
         */

        if (compEnv.codeNext == compEnv.codeStart) {
            TclEmitPush(TclRegisterNewLiteral(&compEnv, "0", 1),
                    &compEnv);
        }

        /*
         * Add a "done" instruction as the last instruction and change the
         * object into a ByteCode object. Ownership of the literal objects and
         * aux data items is given to the ByteCode object.
         */

        TclEmitOpcode(INST_DONE, &compEnv);
        TclInitByteCodeObj(objPtr, &compEnv);
        objPtr->typePtr = &exprCodeType;
        TclFreeCompileEnv(&compEnv);
        codePtr = (ByteCode *) objPtr->internalRep.otherValuePtr;
#ifdef TCL_COMPILE_DEBUG
        if (tclTraceCompile == 2) {
            TclPrintByteCodeObj(interp, objPtr);
            fflush(stdout);
        }
#endif /* TCL_COMPILE_DEBUG */
    }

    Tcl_ResetResult(interp);

    /*
     * Increment the code's ref count while it is being executed. If
     * afterwards no references to it remain, free the code.
     */

    codePtr->refCount++;
    result = TclExecuteByteCode(interp, codePtr);
    codePtr->refCount--;
    if (codePtr->refCount <= 0) {
        TclCleanupByteCode(codePtr);
    }

    /*
     * If the expression evaluated successfully, store a pointer to its value
     * object in resultPtrPtr then restore the old interpreter result. We
     * increment the object's ref count to reflect the reference that we are
     * returning to the caller. We also decrement the ref count of the
     * interpreter's result object after calling Tcl_SetResult since we next
     * store into that field directly.
     */

    if (result == TCL_OK) {
        *resultPtrPtr = iPtr->objResultPtr;
        Tcl_IncrRefCount(iPtr->objResultPtr);

        Tcl_SetObjResult(interp, saveObjPtr);
    }
    TclDecrRefCount(saveObjPtr);
    return result;
}

/*
 *----------------------------------------------------------------------
 *
 * DupExprCodeInternalRep --
 *
 *      Part of the Tcl object type implementation for Tcl expression
 *      bytecode.  We do not copy the bytecode intrep.  Instead, we
 *      return without setting copyPtr->typePtr, so the copy is a plain
 *      string copy of the expression value, and if it is to be used
 *      as a compiled expression, it will just need a recompile.
 *
 *      This makes sense, because with Tcl's copy-on-write practices,
 *      the usual (only?) time Tcl_DuplicateObj() will be called is
 *      when the copy is about to be modified, which would invalidate
 *      any copied bytecode anyway.  The only reason it might make sense
 *      to copy the bytecode is if we had some modifying routines that
 *      operated directly on the intrep, like we do for lists and dicts.
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      None.
 *
 *----------------------------------------------------------------------
 */

static void
DupExprCodeInternalRep(
    Tcl_Obj *srcPtr,
    Tcl_Obj *copyPtr)
{
    return;
}

/*
 *----------------------------------------------------------------------
 *
 * FreeExprCodeInternalRep --
 *
 *      Part of the Tcl object type implementation for Tcl expression
 *      bytecode.  Frees the storage allocated to hold the internal rep,
 *      unless ref counts indicate bytecode execution is still in progress.
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      May free allocated memory.  Leaves objPtr untyped.
 *----------------------------------------------------------------------
 */

static void
FreeExprCodeInternalRep(
    Tcl_Obj *objPtr)
{
    ByteCode *codePtr = (ByteCode *) objPtr->internalRep.otherValuePtr;

    codePtr->refCount--;
    if (codePtr->refCount <= 0) {
        TclCleanupByteCode(codePtr);
    }
    objPtr->typePtr = NULL;
    objPtr->internalRep.otherValuePtr = NULL;
}

/*
 *----------------------------------------------------------------------
 *
 * TclCompEvalObj --
 *
 *      This procedure evaluates the script contained in a Tcl_Obj by first
 *      compiling it and then passing it to TclExecuteByteCode.
 *
 * Results:
 *      The return value is one of the return codes defined in tcl.h (such as
 *      TCL_OK), and interp->objResultPtr refers to a Tcl object that either
 *      contains the result of executing the code or an error message.
 *
 * Side effects:
 *      Almost certainly, depending on the ByteCode's instructions.
 *
 *----------------------------------------------------------------------
 */

int
TclCompEvalObj(
    Tcl_Interp *interp,
    Tcl_Obj *objPtr,
    const CmdFrame *invoker,
    int word)
{
    register Interp *iPtr = (Interp *) interp;
    register ByteCode *codePtr; /* Tcl Internal type of bytecode. */
    int result;
    Namespace *namespacePtr;

    /*
     * Check that the interpreter is ready to execute scripts. Note that we
     * manage the interp's runlevel here: it is a small white lie (maybe), but
     * saves a ++/-- pair at each invocation. Amazingly enough, the impact on
     * performance is noticeable.
     */

    iPtr->numLevels++;
    if (TclInterpReady(interp) == TCL_ERROR) {
        result = TCL_ERROR;
        goto done;
    }

    namespacePtr = iPtr->varFramePtr->nsPtr;

    /*
     * If the object is not already of tclByteCodeType, compile it (and reset
     * the compilation flags in the interpreter; this should be done after any
     * compilation). Otherwise, check that it is "fresh" enough.
     */

    if (objPtr->typePtr == &tclByteCodeType) {
        /*
         * Make sure the Bytecode hasn't been invalidated by, e.g., someone
         * redefining a command with a compile procedure (this might make the
         * compiled code wrong). The object needs to be recompiled if it was
         * compiled in/for a different interpreter, or for a different
         * namespace, or for the same namespace but with different name
         * resolution rules. Precompiled objects, however, are immutable and
         * therefore they are not recompiled, even if the epoch has changed.
         *
         * To be pedantically correct, we should also check that the
         * originating procPtr is the same as the current context procPtr
         * (assuming one exists at all - none for global level). This code is
         * #def'ed out because [info body] was changed to never return a
         * bytecode type object, which should obviate us from the extra checks
         * here.
         */

        codePtr = (ByteCode *) objPtr->internalRep.otherValuePtr;
        if (((Interp *) *codePtr->interpHandle != iPtr)
                || (codePtr->compileEpoch != iPtr->compileEpoch)
                || (codePtr->nsPtr != namespacePtr)
                || (codePtr->nsEpoch != namespacePtr->resolverEpoch)) {
            if (codePtr->flags & TCL_BYTECODE_PRECOMPILED) {
                if ((Interp *) *codePtr->interpHandle != iPtr) {
                    Tcl_Panic("Tcl_EvalObj: compiled script jumped interps");
                }
                codePtr->compileEpoch = iPtr->compileEpoch;
            } else {
                /*
                 * This byteCode is invalid: free it and recompile.
                 */

                objPtr->typePtr->freeIntRepProc(objPtr);
                goto recompileObj;
            }
        }

        /*
         * Increment the code's ref count while it is being executed. If
         * afterwards no references to it remain, free the code.
         */

    runCompiledObj:
        codePtr->refCount++;
        result = TclExecuteByteCode(interp, codePtr);
        codePtr->refCount--;
        if (codePtr->refCount <= 0) {
            TclCleanupByteCode(codePtr);
        }
        goto done;
    }

    recompileObj:
    iPtr->errorLine = 1;

    /*
     * TIP #280. Remember the invoker for a moment in the interpreter
     * structures so that the byte code compiler can pick it up when
     * initializing the compilation environment, i.e. the extended location
     * information.
     */

    iPtr->invokeCmdFramePtr = invoker;
    iPtr->invokeWord = word;
    tclByteCodeType.setFromAnyProc(interp, objPtr);
    iPtr->invokeCmdFramePtr = NULL;
    codePtr = (ByteCode *) objPtr->internalRep.otherValuePtr;
    goto runCompiledObj;

    done:
    iPtr->numLevels--;
    return result;
}

/*
 *----------------------------------------------------------------------
 *
 * TclIncrObj --
 *
 *      Increment an integeral value in a Tcl_Obj by an integeral value held
 *      in another Tcl_Obj. Caller is responsible for making sure we can
 *      update the first object.
 *
 * Results:
 *      TCL_ERROR if either object is non-integer, and TCL_OK otherwise. On
 *      error, an error message is left in the interpreter (if it is not NULL,
 *      of course).
 *
 * Side effects:
 *      valuePtr gets the new incrmented value.
 *
 *----------------------------------------------------------------------
 */

int
TclIncrObj(
    Tcl_Interp *interp,
    Tcl_Obj *valuePtr,
    Tcl_Obj *incrPtr)
{
    ClientData ptr1, ptr2;
    int type1, type2;
    mp_int value, incr;

    if (Tcl_IsShared(valuePtr)) {
        Tcl_Panic("%s called with shared object", "TclIncrObj");
    }

    if (GetNumberFromObj(NULL, valuePtr, &ptr1, &type1) != TCL_OK) {
        /*
         * Produce error message (reparse?!)
         */

        return TclGetIntFromObj(interp, valuePtr, &type1);
    }
    if (GetNumberFromObj(NULL, incrPtr, &ptr2, &type2) != TCL_OK) {
        /*
         * Produce error message (reparse?!)
         */

        TclGetIntFromObj(interp, incrPtr, &type1);
        Tcl_AddErrorInfo(interp, "\n    (reading increment)");
        return TCL_ERROR;
    }

    if ((type1 == TCL_NUMBER_LONG) && (type2 == TCL_NUMBER_LONG)) {
        long augend = *((const long *) ptr1);
        long addend = *((const long *) ptr2);
        long sum = augend + addend;

        /*
         * Overflow when (augend and sum have different sign) and (augend and
         * addend have the same sign). This is encapsulated in the Overflowing
         * macro.
         */

        if (!Overflowing(augend, addend, sum)) {
            TclSetLongObj(valuePtr, sum);
            return TCL_OK;
        }
#ifndef NO_WIDE_TYPE
        {
            Tcl_WideInt w1 = (Tcl_WideInt) augend;
            Tcl_WideInt w2 = (Tcl_WideInt) addend;

            /*
             * We know the sum value is outside the long range, so we use the
             * macro form that doesn't range test again.
             */

            TclSetWideIntObj(valuePtr, w1 + w2);
            return TCL_OK;
        }
#endif
    }

    if ((type1 == TCL_NUMBER_DOUBLE) || (type1 == TCL_NUMBER_NAN)) {
        /*
         * Produce error message (reparse?!)
         */

        return TclGetIntFromObj(interp, valuePtr, &type1);
    }
    if ((type2 == TCL_NUMBER_DOUBLE) || (type2 == TCL_NUMBER_NAN)) {
        /*
         * Produce error message (reparse?!)
         */

        TclGetIntFromObj(interp, incrPtr, &type1);
        Tcl_AddErrorInfo(interp, "\n    (reading increment)");
        return TCL_ERROR;
    }

#ifndef NO_WIDE_TYPE
    if ((type1 != TCL_NUMBER_BIG) && (type2 != TCL_NUMBER_BIG)) {
        Tcl_WideInt w1, w2, sum;

        TclGetWideIntFromObj(NULL, valuePtr, &w1);
        TclGetWideIntFromObj(NULL, incrPtr, &w2);
        sum = w1 + w2;

        /*
         * Check for overflow.
         */

        if (!Overflowing(w1, w2, sum)) {
            Tcl_SetWideIntObj(valuePtr, sum);
            return TCL_OK;
        }
    }
#endif

    Tcl_TakeBignumFromObj(interp, valuePtr, &value);
    Tcl_GetBignumFromObj(interp, incrPtr, &incr);
    mp_add(&value, &incr, &value);
    mp_clear(&incr);
    Tcl_SetBignumObj(valuePtr, &value);
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * TclExecuteByteCode --
 *
 *      This procedure executes the instructions of a ByteCode structure. It
 *      returns when a "done" instruction is executed or an error occurs.
 *
 * Results:
 *      The return value is one of the return codes defined in tcl.h (such as
 *      TCL_OK), and interp->objResultPtr refers to a Tcl object that either
 *      contains the result of executing the code or an error message.
 *
 * Side effects:
 *      Almost certainly, depending on the ByteCode's instructions.
 *
 *----------------------------------------------------------------------
 */

int
TclExecuteByteCode(
    Tcl_Interp *interp,         /* Token for command interpreter. */
    ByteCode *codePtr)          /* The bytecode sequence to interpret. */
{
    /*
     * Compiler cast directive - not a real variable.
     *     Interp *iPtr = (Interp *) interp;
     */
#define iPtr ((Interp *) interp)

    /*
     * Check just the read-traced/write-traced bit of a variable.
     */

#define ReadTraced(varPtr) ((varPtr)->flags & VAR_TRACED_READ)
#define WriteTraced(varPtr) ((varPtr)->flags & VAR_TRACED_WRITE)

    /*
     * Constants: variables that do not change during the execution, used
     * sporadically.
     */

    ExecStack *esPtr;
    Tcl_Obj **initTosPtr;       /* Stack top at start of execution. */
    ptrdiff_t *initCatchTop;    /* Catch stack top at start of execution. */
    Var *compiledLocals;
    Namespace *namespacePtr;
    CmdFrame *bcFramePtr;       /* TIP #280: Structure for tracking lines. */
    Tcl_Obj **constants = &iPtr->execEnvPtr->constants[0];

    /*
     * Globals: variables that store state, must remain valid at all times.
     */

    ptrdiff_t *catchTop;
    register Tcl_Obj **tosPtr;  /* Cached pointer to top of evaluation
                                 * stack. */
    register unsigned char *pc = codePtr->codeStart;
                                /* The current program counter. */
    int instructionCount = 0;   /* Counter that is used to work out when to
                                 * call Tcl_AsyncReady() */
    Tcl_Obj *expandNestList = NULL;
    int checkInterp = 0;        /* Indicates when a check of interp readyness
                                 * is necessary. Set by CACHE_STACK_INFO() */

    /*
     * Transfer variables - needed only between opcodes, but not while
     * executing an instruction.
     */

    register int cleanup;
    Tcl_Obj *objResultPtr;

    /*
     * Result variable - needed only when going to checkForcatch or other
     * error handlers; also used as local in some opcodes.
     */

    int result = TCL_OK;        /* Return code returned after execution. */

    /*
     * Locals - variables that are used within opcodes or bounded sections of
     * the file (jumps between opcodes within a family).
     * NOTE: These are now defined locally where needed.
     */

#ifdef TCL_COMPILE_DEBUG
    int traceInstructions = (tclTraceExec == 3);
    char cmdNameBuf[21];
#endif
    char *curInstName = NULL;

    /*
     * The execution uses a unified stack: first the catch stack, immediately
     * above it a CmdFrame, then the execution stack.
     *
     * Make sure the catch stack is large enough to hold the maximum number of
     * catch commands that could ever be executing at the same time (this will
     * be no more than the exception range array's depth). Make sure the
     * execution stack is large enough to execute this ByteCode.
     */

    catchTop = initCatchTop = (ptrdiff_t *) (
        GrowEvaluationStack(iPtr->execEnvPtr,
                codePtr->maxExceptDepth + sizeof(CmdFrame) +
                    codePtr->maxStackDepth, 0) - 1);
    bcFramePtr = (CmdFrame *) (initCatchTop + codePtr->maxExceptDepth + 1);
    tosPtr = initTosPtr = ((Tcl_Obj **) (bcFramePtr + 1)) - 1;
    esPtr = iPtr->execEnvPtr->execStackPtr;

    /*
     * TIP #280: Initialize the frame. Do not push it yet.
     */

    bcFramePtr->type = ((codePtr->flags & TCL_BYTECODE_PRECOMPILED)
            ? TCL_LOCATION_PREBC : TCL_LOCATION_BC);
    bcFramePtr->level = (iPtr->cmdFramePtr ? iPtr->cmdFramePtr->level+1 : 1);
    bcFramePtr->framePtr = iPtr->framePtr;
    bcFramePtr->nextPtr = iPtr->cmdFramePtr;
    bcFramePtr->nline = 0;
    bcFramePtr->line = NULL;

    bcFramePtr->data.tebc.codePtr = codePtr;
    bcFramePtr->data.tebc.pc = NULL;
    bcFramePtr->cmd.str.cmd = NULL;
    bcFramePtr->cmd.str.len = 0;

#ifdef TCL_COMPILE_DEBUG
    if (tclTraceExec >= 2) {
        PrintByteCodeInfo(codePtr);
        fprintf(stdout, "  Starting stack top=%d\n", CURR_DEPTH);
        fflush(stdout);
    }
#endif

#ifdef TCL_COMPILE_STATS
    iPtr->stats.numExecutions++;
#endif

    namespacePtr = iPtr->varFramePtr->nsPtr;
    compiledLocals = iPtr->varFramePtr->compiledLocals;

    /*
     * Loop executing instructions until a "done" instruction, a TCL_RETURN,
     * or some error.
     */

    goto cleanup0;

    /*
     * Targets for standard instruction endings; unrolled for speed in the
     * most frequent cases (instructions that consume up to two stack
     * elements).
     *
     * This used to be a "for(;;)" loop, with each instruction doing its own
     * cleanup.
     */

    {
        Tcl_Obj *valuePtr;

    cleanupV_pushObjResultPtr:
        switch (cleanup) {
        case 0:
            *(++tosPtr) = (objResultPtr);
            goto cleanup0;
        default:
            cleanup -= 2;
            while (cleanup--) {
                valuePtr = POP_OBJECT();
                TclDecrRefCount(valuePtr);
            }
        case 2:
        cleanup2_pushObjResultPtr:
            valuePtr = POP_OBJECT();
            TclDecrRefCount(valuePtr);
        case 1:
        cleanup1_pushObjResultPtr:
            valuePtr = OBJ_AT_TOS;
            TclDecrRefCount(valuePtr);
        }
        OBJ_AT_TOS = objResultPtr;
        goto cleanup0;

    cleanupV:
        switch (cleanup) {
        default:
            cleanup -= 2;
            while (cleanup--) {
                valuePtr = POP_OBJECT();
                TclDecrRefCount(valuePtr);
            }
        case 2:
        cleanup2:
            valuePtr = POP_OBJECT();
            TclDecrRefCount(valuePtr);
        case 1:
        cleanup1:
            valuePtr = POP_OBJECT();
            TclDecrRefCount(valuePtr);
        case 0:
            /*
             * We really want to do nothing now, but this is needed for some
             * compilers (SunPro CC).
             */

            break;
        }
    }
 cleanup0:

#ifdef TCL_COMPILE_DEBUG
    /*
     * Skip the stack depth check if an expansion is in progress.
     */

    ValidatePcAndStackTop(codePtr, pc, CURR_DEPTH, 0,
            /*checkStack*/ expandNestList == NULL);
    if (traceInstructions) {
        fprintf(stdout, "%2d: %2d ", iPtr->numLevels, (int) CURR_DEPTH);
        TclPrintInstruction(codePtr, pc);
        fflush(stdout);
    }
#endif /* TCL_COMPILE_DEBUG */

#ifdef TCL_COMPILE_STATS
    iPtr->stats.instructionCount[*pc]++;
#endif

    /*
     * Check for asynchronous handlers [Bug 746722]; we do the check every
     * ASYNC_CHECK_COUNT_MASK instruction, of the form (2**n-1).
     */

    if ((instructionCount++ & ASYNC_CHECK_COUNT_MASK) == 0) {
        /*
         * Check for asynchronous handlers [Bug 746722]; we do the check every
         * ASYNC_CHECK_COUNT_MASK instruction, of the form (2**n-<1).
         */

        if (TclAsyncReady(iPtr)) {
            int localResult;

            DECACHE_STACK_INFO();
            localResult = Tcl_AsyncInvoke(interp, result);
            CACHE_STACK_INFO();
            if (localResult == TCL_ERROR) {
                result = localResult;
                goto checkForCatch;
            }
        }
        if (TclLimitReady(iPtr->limit)) {
            int localResult;

            DECACHE_STACK_INFO();
            localResult = Tcl_LimitCheck(interp);
            CACHE_STACK_INFO();
            if (localResult == TCL_ERROR) {
                result = localResult;
                goto checkForCatch;
            }
        }
    }

     TCL_DTRACE_INST_NEXT();

    /*
     * These two instructions account for 26% of all instructions (according
     * to measurements on tclbench by Ben Vitale
     * [http://www.cs.toronto.edu/syslab/pubs/tcl2005-vitale-zaleski.pdf]
     * Resolving them before the switch reduces the cost of branch
     * mispredictions, seems to improve runtime by 5% to 15%, and (amazingly!)
     * reduces total obj size.
     */

    if (*pc == INST_LOAD_SCALAR1) {
        goto instLoadScalar1;
    } else if (*pc == INST_PUSH1) {
        goto instPush1Peephole;
    }

    switch (*pc) {
    case INST_SYNTAX:
    case INST_RETURN_IMM: {
        int code = TclGetInt4AtPtr(pc+1);
        int level = TclGetUInt4AtPtr(pc+5);

        /*
         * OBJ_AT_TOS is returnOpts, OBJ_UNDER_TOS is resultObjPtr.
         */

        TRACE(("%u %u => ", code, level));
        result = TclProcessReturn(interp, code, level, OBJ_AT_TOS);
        if (result == TCL_OK) {
            TRACE_APPEND(("continuing to next instruction (result=\"%.30s\")",
                    O2S(objResultPtr)));
            NEXT_INST_F(9, 1, 0);
        } else {
            Tcl_SetObjResult(interp, OBJ_UNDER_TOS);
            if (*pc == INST_SYNTAX) {
                iPtr->flags &= ~ERR_ALREADY_LOGGED;
            }
            cleanup = 2;
            goto processExceptionReturn;
        }
    }

    case INST_RETURN_STK:
        TRACE(("=> "));
        objResultPtr = POP_OBJECT();
        result = Tcl_SetReturnOptions(interp, OBJ_AT_TOS);
        Tcl_DecrRefCount(OBJ_AT_TOS);
        OBJ_AT_TOS = objResultPtr;
        if (result == TCL_OK) {
            TRACE_APPEND(("continuing to next instruction (result=\"%.30s\")",
                    O2S(objResultPtr)));
            NEXT_INST_F(1, 0, 0);
        } else {
            Tcl_SetObjResult(interp, objResultPtr);
            cleanup = 1;
            goto processExceptionReturn;
        }

    case INST_DONE:
        if (tosPtr > initTosPtr) {
            /*
             * Set the interpreter's object result to point to the topmost
             * object from the stack, and check for a possible [catch]. The
             * stackTop's level and refCount will be handled by "processCatch"
             * or "abnormalReturn".
             */

            Tcl_SetObjResult(interp, OBJ_AT_TOS);
#ifdef TCL_COMPILE_DEBUG
            TRACE_WITH_OBJ(("=> return code=%d, result=", result),
                    iPtr->objResultPtr);
            if (traceInstructions) {
                fprintf(stdout, "\n");
            }
#endif
            goto checkForCatch;
        } else {
            (void) POP_OBJECT();
            goto abnormalReturn;
        }

    case INST_PUSH1:
    instPush1Peephole:
        PUSH_OBJECT(codePtr->objArrayPtr[TclGetUInt1AtPtr(pc+1)]);
        TRACE_WITH_OBJ(("%u => ", TclGetInt1AtPtr(pc+1)), OBJ_AT_TOS);
        pc += 2;
#if !TCL_COMPILE_DEBUG
        /*
         * Runtime peephole optimisation: check if we are pushing again.
         */

        if (*pc == INST_PUSH1) {
            TCL_DTRACE_INST_NEXT();
            goto instPush1Peephole;
        }
#endif
        NEXT_INST_F(0, 0, 0);

    case INST_PUSH4:
        objResultPtr = codePtr->objArrayPtr[TclGetUInt4AtPtr(pc+1)];
        TRACE_WITH_OBJ(("%u => ", TclGetUInt4AtPtr(pc+1)), objResultPtr);
        NEXT_INST_F(5, 0, 1);

    case INST_POP: {
        Tcl_Obj *valuePtr;

        TRACE_WITH_OBJ(("=> discarding "), OBJ_AT_TOS);
        valuePtr = POP_OBJECT();
        TclDecrRefCount(valuePtr);

        /*
         * Runtime peephole optimisation: an INST_POP is scheduled at the end
         * of most commands. If the next instruction is an INST_START_CMD,
         * fall through to it.
         */

        pc++;
#if !TCL_COMPILE_DEBUG
        if (*pc == INST_START_CMD) {
            TCL_DTRACE_INST_NEXT();
            goto instStartCmdPeephole;
        }
#endif
        NEXT_INST_F(0, 0, 0);
    }

    case INST_START_CMD:
#if !TCL_COMPILE_DEBUG
    instStartCmdPeephole:
#endif
        /*
         * Remark that if the interpreter is marked for deletion its
         * compileEpoch is modified, so that the epoch check also verifies
         * that the interp is not deleted. If no outside call has been made
         * since the last check, it is safe to omit the check.
         */

        iPtr->cmdCount += TclGetUInt4AtPtr(pc+5);
        if (!checkInterp) {
        instStartCmdOK:
            NEXT_INST_F(9, 0, 0);
        } else if (((codePtr->compileEpoch == iPtr->compileEpoch)
                && (codePtr->nsEpoch == namespacePtr->resolverEpoch))
                || (codePtr->flags & TCL_BYTECODE_PRECOMPILED)) {
            checkInterp = 0;
            goto instStartCmdOK;
        } else {
            const char *bytes;
            int length, opnd;
            Tcl_Obj *newObjResultPtr;

            bytes = GetSrcInfoForPc(pc, codePtr, &length);
            DECACHE_STACK_INFO();
            result = Tcl_EvalEx(interp, bytes, length, 0);
            CACHE_STACK_INFO();
            if (result != TCL_OK) {
                cleanup = 0;
                goto processExceptionReturn;
            }
            opnd = TclGetUInt4AtPtr(pc+1);
            objResultPtr = Tcl_GetObjResult(interp);
            TclNewObj(newObjResultPtr);
            Tcl_IncrRefCount(newObjResultPtr);
            iPtr->objResultPtr = newObjResultPtr;
            NEXT_INST_V(opnd, 0, -1);
        }

    case INST_DUP:
        objResultPtr = OBJ_AT_TOS;
        TRACE_WITH_OBJ(("=> "), objResultPtr);
        NEXT_INST_F(1, 0, 1);

    case INST_OVER: {
        int opnd;

        opnd = TclGetUInt4AtPtr(pc+1);
        objResultPtr = OBJ_AT_DEPTH(opnd);
        TRACE_WITH_OBJ(("=> "), objResultPtr);
        NEXT_INST_F(5, 0, 1);
    }

    case INST_REVERSE: {
        int opnd;
        Tcl_Obj **a, **b;

        opnd = TclGetUInt4AtPtr(pc+1);
        a = tosPtr-(opnd-1);
        b = tosPtr;
        while (a<b) {
            Tcl_Obj *temp = *a;
            *a = *b;
            *b = temp;
            a++; b--;
        }
        NEXT_INST_F(5, 0, 0);
    }

    case INST_CONCAT1: {
        int opnd, length, appendLen = 0;
        char *bytes, *p;
        Tcl_Obj **currPtr;

        opnd = TclGetUInt1AtPtr(pc+1);

        /*
         * Compute the length to be appended.
         */

        for (currPtr=&OBJ_AT_DEPTH(opnd-2); currPtr<=&OBJ_AT_TOS; currPtr++) {
            bytes = TclGetStringFromObj(*currPtr, &length);
            if (bytes != NULL) {
                appendLen += length;
            }
        }

        /*
         * If nothing is to be appended, just return the first object by
         * dropping all the others from the stack; this saves both the
         * computation and copy of the string rep of the first object,
         * enabling the fast '$x[set x {}]' idiom for 'K $x [set x {}]'.
         */

        if (appendLen == 0) {
            TRACE_WITH_OBJ(("%u => ", opnd), objResultPtr);
            NEXT_INST_V(2, (opnd-1), 0);
        }

        /*
         * If the first object is shared, we need a new obj for the result;
         * otherwise, we can reuse the first object. In any case, make sure it
         * has enough room to accomodate all the concatenated bytes. Note that
         * if it is unshared its bytes are copied by ckrealloc, so that we set
         * the loop parameters to avoid copying them again: p points to the
         * end of the already copied bytes, currPtr to the second object.
         */

        objResultPtr = OBJ_AT_DEPTH(opnd-1);
        bytes = TclGetStringFromObj(objResultPtr, &length);
#if !TCL_COMPILE_DEBUG
        if (bytes != tclEmptyStringRep && !Tcl_IsShared(objResultPtr)) {
            TclFreeIntRep(objResultPtr);
            objResultPtr->typePtr = NULL;
            objResultPtr->bytes = ckrealloc(bytes, (length + appendLen + 1));
            objResultPtr->length = length + appendLen;
            p = TclGetString(objResultPtr) + length;
            currPtr = &OBJ_AT_DEPTH(opnd - 2);
        } else {
#endif
            p = (char *) ckalloc((unsigned) (length + appendLen + 1));
            TclNewObj(objResultPtr);
            objResultPtr->bytes = p;
            objResultPtr->length = length + appendLen;
            currPtr = &OBJ_AT_DEPTH(opnd - 1);
#if !TCL_COMPILE_DEBUG
        }
#endif

        /*
         * Append the remaining characters.
         */

        for (; currPtr <= &OBJ_AT_TOS; currPtr++) {
            bytes = TclGetStringFromObj(*currPtr, &length);
            if (bytes != NULL) {
                memcpy(p, bytes, (size_t) length);
                p += length;
            }
        }
        *p = '\0';

        TRACE_WITH_OBJ(("%u => ", opnd), objResultPtr);
        NEXT_INST_V(2, opnd, 1);
    }

    case INST_EXPAND_START: {
        /*
         * Push an element to the expandNestList. This records the current
         * stack depth - i.e., the point in the stack where the expanded
         * command starts.
         *
         * Use a Tcl_Obj as linked list element; slight mem waste, but faster
         * allocation than ckalloc. This also abuses the Tcl_Obj structure, as
         * we do not define a special tclObjType for it. It is not dangerous
         * as the obj is never passed anywhere, so that all manipulations are
         * performed here and in INST_INVOKE_EXPANDED (in case of an expansion
         * error, also in INST_EXPAND_STKTOP).
         */

        Tcl_Obj *objPtr;

        TclNewObj(objPtr);
        objPtr->internalRep.twoPtrValue.ptr1 = (VOID *) CURR_DEPTH;
        objPtr->internalRep.twoPtrValue.ptr2 = (VOID *) expandNestList;
        expandNestList = objPtr;
        NEXT_INST_F(1, 0, 0);
    }

    case INST_EXPAND_STKTOP: {
        int objc, length, i;
        Tcl_Obj **objv, *valuePtr;
        ptrdiff_t moved;

        /*
         * Make sure that the element at stackTop is a list; if not, just
         * leave with an error. Note that the element from the expand list
         * will be removed at checkForCatch.
         */

        valuePtr = OBJ_AT_TOS;
        if (TclListObjGetElements(interp, valuePtr, &objc, &objv) != TCL_OK){
            TRACE_WITH_OBJ(("%.30s => ERROR: ", O2S(valuePtr)),
                    Tcl_GetObjResult(interp));
            result = TCL_ERROR;
            goto checkForCatch;
        }
        (void) POP_OBJECT();

        /*
         * Make sure there is enough room in the stack to expand this list
         * *and* process the rest of the command (at least up to the next
         * argument expansion or command end). The operand is the current
         * stack depth, as seen by the compiler.
         */

        length = objc + (codePtr->maxStackDepth - TclGetInt4AtPtr(pc+1));
        DECACHE_STACK_INFO();
        moved = (GrowEvaluationStack(iPtr->execEnvPtr, length, 1) - 1)
                - (Tcl_Obj **) initCatchTop;

        if (moved) {
            /*
             * Change the global data to point to the new stack.
             */

            initCatchTop += moved;
            catchTop += moved;
            initTosPtr += moved;
            tosPtr += moved;
            esPtr = iPtr->execEnvPtr->execStackPtr;
        }

        /*
         * Expand the list at stacktop onto the stack; free the list. Knowing
         * that it has a freeIntRepProc we use Tcl_DecrRefCount().
         */

        for (i = 0; i < objc; i++) {
            PUSH_OBJECT(objv[i]);
        }

        Tcl_DecrRefCount(valuePtr);
        NEXT_INST_F(5, 0, 0);
    }

    {
        /*
         * INVOCATION BLOCK
         */

        int objc, pcAdjustment;

    case INST_INVOKE_EXPANDED:
        {
            Tcl_Obj *objPtr = expandNestList;

            expandNestList = (Tcl_Obj *) objPtr->internalRep.twoPtrValue.ptr2;
            objc = CURR_DEPTH
                    - (ptrdiff_t) objPtr->internalRep.twoPtrValue.ptr1;
            TclDecrRefCount(objPtr);
        }

        if (objc) {
            pcAdjustment = 1;
            goto doInvocation;
        } else {
            /*
             * Nothing was expanded, return {}.
             */

            TclNewObj(objResultPtr);
            NEXT_INST_F(1, 0, 1);
        }

    case INST_INVOKE_STK4:
        objc = TclGetUInt4AtPtr(pc+1);
        pcAdjustment = 5;
        goto doInvocation;

    case INST_INVOKE_STK1:
        objc = TclGetUInt1AtPtr(pc+1);
        pcAdjustment = 2;

    doInvocation:
        {
            Tcl_Obj **objv = &OBJ_AT_DEPTH(objc-1);

#ifdef TCL_COMPILE_DEBUG
            if (tclTraceExec >= 2) {
                int i;

                if (traceInstructions) {
                    strncpy(cmdNameBuf, TclGetString(objv[0]), 20);
                    TRACE(("%u => call ", objc));
                } else {
                    fprintf(stdout, "%d: (%u) invoking ", iPtr->numLevels,
                            (unsigned)(pc - codePtr->codeStart));
                }
                for (i = 0;  i < objc;  i++) {
                    TclPrintObject(stdout, objv[i], 15);
                    fprintf(stdout, " ");
                }
                fprintf(stdout, "\n");
                fflush(stdout);
            }
#endif /*TCL_COMPILE_DEBUG*/

            /*
             * Reset the instructionCount variable, since we're about to check
             * for async stuff anyway while processing TclEvalObjvInternal.
             */

            instructionCount = 1;

            /*
             * Finally, let TclEvalObjvInternal handle the command.
             *
             * TIP #280: Record the last piece of info needed by
             * 'TclGetSrcInfoForPc', and push the frame.
             */

            bcFramePtr->data.tebc.pc = (char *) pc;
            iPtr->cmdFramePtr = bcFramePtr;
            DECACHE_STACK_INFO();
            result = TclEvalObjvInternal(interp, objc, objv,
                    /* call from TEBC */(char *) -1, -1, 0);
            CACHE_STACK_INFO();
            iPtr->cmdFramePtr = iPtr->cmdFramePtr->nextPtr;

            if (result == TCL_OK) {
                Tcl_Obj *objPtr;

#ifndef TCL_COMPILE_DEBUG
                if (*(pc+pcAdjustment) == INST_POP) {
                    NEXT_INST_V((pcAdjustment+1), objc, 0);
                }
#endif
                /*
                 * Push the call's object result and continue execution with
                 * the next instruction.
                 */

                TRACE_WITH_OBJ(("%u => ... after \"%.20s\": TCL_OK, result=",
                        objc, cmdNameBuf), Tcl_GetObjResult(interp));

                objResultPtr = Tcl_GetObjResult(interp);

                /*
                 * Reset the interp's result to avoid possible duplications of
                 * large objects [Bug 781585]. We do not call Tcl_ResetResult
                 * to avoid any side effects caused by the resetting of
                 * errorInfo and errorCode [Bug 804681], which are not needed
                 * here. We chose instead to manipulate the interp's object
                 * result directly.
                 *
                 * Note that the result object is now in objResultPtr, it
                 * keeps the refCount it had in its role of
                 * iPtr->objResultPtr.
                 */

                TclNewObj(objPtr);
                Tcl_IncrRefCount(objPtr);
                iPtr->objResultPtr = objPtr;
                NEXT_INST_V(pcAdjustment, objc, -1);
            } else {
                cleanup = objc;
                goto processExceptionReturn;
            }
        }

#if TCL_SUPPORT_84_BYTECODE
    case INST_CALL_BUILTIN_FUNC1: {
        /*
         * Call one of the built-in pre-8.5 Tcl math functions. This
         * translates to INST_INVOKE_STK1 with the first argument of
         * ::tcl::mathfunc::$objv[0]. We need to insert the named math
         * function into the stack.
         */

        int opnd, numArgs;
        Tcl_Obj *objPtr;

        opnd = TclGetUInt1AtPtr(pc+1);
        if ((opnd < 0) || (opnd > LAST_BUILTIN_FUNC)) {
            TRACE(("UNRECOGNIZED BUILTIN FUNC CODE %d\n", opnd));
            Tcl_Panic("TclExecuteByteCode: unrecognized builtin function code %d", opnd);
        }

        objPtr = Tcl_NewStringObj("::tcl::mathfunc::", 17);
        Tcl_AppendToObj(objPtr, tclBuiltinFuncTable[opnd].name, -1);

        /*
         * Only 0, 1 or 2 args.
         */

        numArgs = tclBuiltinFuncTable[opnd].numArgs;
        if (numArgs == 0) {
            PUSH_OBJECT(objPtr);
        } else if (numArgs == 1) {
            Tcl_Obj *tmpPtr1 = POP_OBJECT();
            PUSH_OBJECT(objPtr);
            PUSH_OBJECT(tmpPtr1);
            Tcl_DecrRefCount(tmpPtr1);
        } else {
            Tcl_Obj *tmpPtr1, *tmpPtr2;
            tmpPtr2 = POP_OBJECT();
            tmpPtr1 = POP_OBJECT();
            PUSH_OBJECT(objPtr);
            PUSH_OBJECT(tmpPtr1);
            PUSH_OBJECT(tmpPtr2);
            Tcl_DecrRefCount(tmpPtr1);
            Tcl_DecrRefCount(tmpPtr2);
        }

        objc = numArgs + 1;
        pcAdjustment = 2;
        goto doInvocation;
    }

    case INST_CALL_FUNC1: {
        /*
         * Call a non-builtin Tcl math function previously registered by a
         * call to Tcl_CreateMathFunc pre-8.5. This is essentially
         * INST_INVOKE_STK1 converting the first arg to
         * ::tcl::mathfunc::$objv[0].
         */

        Tcl_Obj *tmpPtr, *objPtr;

        /*
         * Number of arguments. The function name is the 0-th argument.
         */

        objc = TclGetUInt1AtPtr(pc+1);

        objPtr = OBJ_AT_DEPTH(objc-1);
        tmpPtr = Tcl_NewStringObj("::tcl::mathfunc::", 17);
        Tcl_AppendObjToObj(tmpPtr, objPtr);
        Tcl_DecrRefCount(objPtr);

        /*
         * Variation of PUSH_OBJECT.
         */

        OBJ_AT_DEPTH(objc-1) = tmpPtr;
        Tcl_IncrRefCount(tmpPtr);

        pcAdjustment = 2;
        goto doInvocation;
    }
#else
    /*
     * INST_CALL_BUILTIN_FUNC1 and INST_CALL_FUNC1 were made obsolete by the
     * changes to add a ::tcl::mathfunc namespace in 8.5. Optional support
     * remains for existing bytecode precompiled files.
     */

    case INST_CALL_BUILTIN_FUNC1:
        Tcl_Panic("TclExecuteByteCode: obsolete INST_CALL_BUILTIN_FUNC1 found");
    case INST_CALL_FUNC1:
        Tcl_Panic("TclExecuteByteCode: obsolete INST_CALL_FUNC1 found");
#endif
    }

    case INST_EVAL_STK: {
        /*
         * Note to maintainers: it is important that INST_EVAL_STK pop its
         * argument from the stack before jumping to checkForCatch! DO NOT
         * OPTIMISE!
         */

        Tcl_Obj *objPtr = OBJ_AT_TOS;

        DECACHE_STACK_INFO();

        /*
         * TIP #280: The invoking context is left NULL for a dynamically
         * constructed command. We cannot match its lines to the outer
         * context.
         */

        result = TclCompEvalObj(interp, objPtr, NULL, 0);
        CACHE_STACK_INFO();
        if (result == TCL_OK) {
            /*
             * Normal return; push the eval's object result.
             */

            objResultPtr = Tcl_GetObjResult(interp);
            TRACE_WITH_OBJ(("\"%.30s\" => ", O2S(objPtr)),
                    Tcl_GetObjResult(interp));

            /*
             * Reset the interp's result to avoid possible duplications of
             * large objects [Bug 781585]. We do not call Tcl_ResetResult to
             * avoid any side effects caused by the resetting of errorInfo and
             * errorCode [Bug 804681], which are not needed here. We chose
             * instead to manipulate the interp's object result directly.
             *
             * Note that the result object is now in objResultPtr, it keeps
             * the refCount it had in its role of iPtr->objResultPtr.
             */

            TclNewObj(objPtr);
            Tcl_IncrRefCount(objPtr);
            iPtr->objResultPtr = objPtr;
            NEXT_INST_F(1, 1, -1);
        } else {
            cleanup = 1;
            goto processExceptionReturn;
        }
    }

    case INST_EXPR_STK: {
        Tcl_Obj *objPtr, *valuePtr;

        objPtr = OBJ_AT_TOS;
        DECACHE_STACK_INFO();
        /*Tcl_ResetResult(interp);*/
        result = Tcl_ExprObj(interp, objPtr, &valuePtr);
        CACHE_STACK_INFO();
        if (result == TCL_OK) {
            objResultPtr = valuePtr;
            TRACE_WITH_OBJ(("\"%.30s\" => ", O2S(objPtr)), valuePtr);
            NEXT_INST_F(1, 1, -1);      /* Already has right refct. */
        } else {
            TRACE_WITH_OBJ(("\"%.30s\" => ERROR: ", O2S(objPtr)),
                    Tcl_GetObjResult(interp));
            goto checkForCatch;
        }
    }

    /*
     * ---------------------------------------------------------
     *     Start of INST_LOAD instructions.
     *
     * WARNING: more 'goto' here than your doctor recommended! The different
     * instructions set the value of some variables and then jump to some
     * common execution code.
     */
    {
        int opnd, pcAdjustment;
        Tcl_Obj *part1Ptr, *part2Ptr;
        Var *varPtr, *arrayPtr;
        Tcl_Obj *objPtr;

    case INST_LOAD_SCALAR1:
    instLoadScalar1:
        opnd = TclGetUInt1AtPtr(pc+1);
        varPtr = &(compiledLocals[opnd]);
        while (TclIsVarLink(varPtr)) {
            varPtr = varPtr->value.linkPtr;
        }
        TRACE(("%u => ", opnd));
        if (TclIsVarDirectReadable(varPtr)) {
            /*
             * No errors, no traces: just get the value.
             */

            objResultPtr = varPtr->value.objPtr;
            TRACE_APPEND(("%.30s\n", O2S(objResultPtr)));
            NEXT_INST_F(2, 0, 1);
        }
        pcAdjustment = 2;
        cleanup = 0;
        arrayPtr = NULL;
        part1Ptr = part2Ptr = NULL;
        goto doCallPtrGetVar;

    case INST_LOAD_SCALAR4:
        opnd = TclGetUInt4AtPtr(pc+1);
        varPtr = &(compiledLocals[opnd]);
        while (TclIsVarLink(varPtr)) {
            varPtr = varPtr->value.linkPtr;
        }
        TRACE(("%u => ", opnd));
        if (TclIsVarDirectReadable(varPtr)) {
            /*
             * No errors, no traces: just get the value.
             */

            objResultPtr = varPtr->value.objPtr;
            TRACE_APPEND(("%.30s\n", O2S(objResultPtr)));
            NEXT_INST_F(5, 0, 1);
        }
        pcAdjustment = 5;
        cleanup = 0;
        arrayPtr = NULL;
        part1Ptr = part2Ptr = NULL;
        goto doCallPtrGetVar;

    case INST_LOAD_ARRAY4:
        opnd = TclGetUInt4AtPtr(pc+1);
        pcAdjustment = 5;
        goto doLoadArray;

    case INST_LOAD_ARRAY1:
        opnd = TclGetUInt1AtPtr(pc+1);
        pcAdjustment = 2;

    doLoadArray:
        part1Ptr = NULL;
        part2Ptr = OBJ_AT_TOS;
        arrayPtr = &(compiledLocals[opnd]);
        while (TclIsVarLink(arrayPtr)) {
            arrayPtr = arrayPtr->value.linkPtr;
        }
        TRACE(("%u \"%.30s\" => ", opnd, O2S(part2Ptr)));
        if (TclIsVarArray(arrayPtr) && !ReadTraced(arrayPtr)) {
            varPtr = VarHashFindVar(arrayPtr->value.tablePtr, part2Ptr);
            if (varPtr && TclIsVarDirectReadable(varPtr)) {
                /*
                 * No errors, no traces: just get the value.
                 */

                objResultPtr = varPtr->value.objPtr;
                TRACE_APPEND(("%.30s\n", O2S(objResultPtr)));
                NEXT_INST_F(pcAdjustment, 1, 1);
            }
        }
        varPtr = TclLookupArrayElement(interp, part1Ptr, part2Ptr,
                TCL_LEAVE_ERR_MSG, "read", 0, 1, arrayPtr, opnd);
        if (varPtr == NULL) {
            TRACE_APPEND(("ERROR: %.30s\n",
                                 O2S(Tcl_GetObjResult(interp))));
            result = TCL_ERROR;
            goto checkForCatch;
        }
        cleanup = 1;
        goto doCallPtrGetVar;

    case INST_LOAD_ARRAY_STK:
        cleanup = 2;
        part2Ptr = OBJ_AT_TOS;          /* element name */
        objPtr = OBJ_UNDER_TOS;         /* array name */
        TRACE(("\"%.30s(%.30s)\" => ", O2S(objPtr), O2S(part2Ptr)));
        goto doLoadStk;

    case INST_LOAD_STK:
    case INST_LOAD_SCALAR_STK:
        cleanup = 1;
        part2Ptr = NULL;
        objPtr = OBJ_AT_TOS;            /* variable name */
        TRACE(("\"%.30s\" => ", O2S(objPtr)));

    doLoadStk:
        part1Ptr = objPtr;
        varPtr = TclObjLookupVarEx(interp, part1Ptr, part2Ptr,
                TCL_LEAVE_ERR_MSG, "read", /*createPart1*/0, /*createPart2*/1,
                &arrayPtr);
        if (varPtr) {
            if (TclIsVarDirectReadable2(varPtr, arrayPtr)) {
                /*
                 * No errors, no traces: just get the value.
                 */

                objResultPtr = varPtr->value.objPtr;
                TRACE_APPEND(("%.30s\n", O2S(objResultPtr)));
                NEXT_INST_V(1, cleanup, 1);
            }
            pcAdjustment = 1;
            opnd = -1;
            goto doCallPtrGetVar;
        } else {
            TRACE_APPEND(("ERROR: %.30s\n", O2S(Tcl_GetObjResult(interp))));
            result = TCL_ERROR;
            goto checkForCatch;
        }

    doCallPtrGetVar:
        /*
         * There are either errors or the variable is traced: call
         * TclPtrGetVar to process fully.
         */

        DECACHE_STACK_INFO();
        objResultPtr = TclPtrGetVar(interp, varPtr, arrayPtr,
                part1Ptr, part2Ptr, TCL_LEAVE_ERR_MSG, opnd);
        CACHE_STACK_INFO();
        if (objResultPtr) {
            TRACE_APPEND(("%.30s\n", O2S(objResultPtr)));
            NEXT_INST_V(pcAdjustment, cleanup, 1);
        } else {
            TRACE_APPEND(("ERROR: %.30s\n", O2S(Tcl_GetObjResult(interp))));
            result = TCL_ERROR;
            goto checkForCatch;
        }
    }

    /*
     *     End of INST_LOAD instructions.
     * ---------------------------------------------------------
     */

    /*
     * ---------------------------------------------------------
     *     Start of INST_STORE and related instructions.
     *
     * WARNING: more 'goto' here than your doctor recommended! The different
     * instructions set the value of some variables and then jump to somme
     * common execution code.
     */

    {
        int opnd, pcAdjustment, storeFlags;
        Tcl_Obj *part1Ptr, *part2Ptr;
        Var *varPtr, *arrayPtr;
        Tcl_Obj *objPtr, *valuePtr;

    case INST_STORE_ARRAY4:
        opnd = TclGetUInt4AtPtr(pc+1);
        pcAdjustment = 5;
        goto doStoreArrayDirect;

    case INST_STORE_ARRAY1:
        opnd = TclGetUInt1AtPtr(pc+1);
        pcAdjustment = 2;

    doStoreArrayDirect:
        valuePtr = OBJ_AT_TOS;
        part2Ptr = OBJ_UNDER_TOS;
        arrayPtr = &(compiledLocals[opnd]);
        TRACE(("%u \"%.30s\" <- \"%.30s\" => ", opnd, O2S(part2Ptr),
                O2S(valuePtr)));
        while (TclIsVarLink(arrayPtr)) {
            arrayPtr = arrayPtr->value.linkPtr;
        }
        if (TclIsVarArray(arrayPtr) && !WriteTraced(arrayPtr)) {
            varPtr = VarHashFindVar(arrayPtr->value.tablePtr, part2Ptr);
            if (varPtr && TclIsVarDirectWritable(varPtr)) {
                tosPtr--;
                Tcl_DecrRefCount(OBJ_AT_TOS);
                OBJ_AT_TOS = valuePtr;
                goto doStoreVarDirect;
            }
        }
        cleanup = 2;
        storeFlags = TCL_LEAVE_ERR_MSG;
        part1Ptr = NULL;
        goto doStoreArrayDirectFailed;

    case INST_STORE_SCALAR4:
        opnd = TclGetUInt4AtPtr(pc+1);
        pcAdjustment = 5;
        goto doStoreScalarDirect;

    case INST_STORE_SCALAR1:
        opnd = TclGetUInt1AtPtr(pc+1);
        pcAdjustment = 2;

    doStoreScalarDirect:
        valuePtr = OBJ_AT_TOS;
        varPtr = &(compiledLocals[opnd]);
        TRACE(("%u <- \"%.30s\" => ", opnd, O2S(valuePtr)));
        while (TclIsVarLink(varPtr)) {
            varPtr = varPtr->value.linkPtr;
        }
        if (TclIsVarDirectWritable(varPtr)) {
    doStoreVarDirect:
            /*
             * No traces, no errors, plain 'set': we can safely inline. The
             * value *will* be set to what's requested, so that the stack top
             * remains pointing to the same Tcl_Obj.
             */

            valuePtr = varPtr->value.objPtr;
            if (valuePtr != NULL) {
                TclDecrRefCount(valuePtr);
            }
            objResultPtr = OBJ_AT_TOS;
            varPtr->value.objPtr = objResultPtr;
#ifndef TCL_COMPILE_DEBUG
            if (*(pc+pcAdjustment) == INST_POP) {
                tosPtr--;
                NEXT_INST_F((pcAdjustment+1), 0, 0);
            }
#else
            TRACE_APPEND(("%.30s\n", O2S(objResultPtr)));
#endif
            Tcl_IncrRefCount(objResultPtr);
            NEXT_INST_F(pcAdjustment, 0, 0);
        }
        storeFlags = TCL_LEAVE_ERR_MSG;
        part1Ptr = NULL;
        goto doStoreScalar;

    case INST_LAPPEND_STK:
        valuePtr = OBJ_AT_TOS; /* value to append */
        part2Ptr = NULL;
        storeFlags = (TCL_LEAVE_ERR_MSG | TCL_APPEND_VALUE
                | TCL_LIST_ELEMENT | TCL_TRACE_READS);
        goto doStoreStk;

    case INST_LAPPEND_ARRAY_STK:
        valuePtr = OBJ_AT_TOS; /* value to append */
        part2Ptr = OBJ_UNDER_TOS;
        storeFlags = (TCL_LEAVE_ERR_MSG | TCL_APPEND_VALUE
                | TCL_LIST_ELEMENT | TCL_TRACE_READS);
        goto doStoreStk;

    case INST_APPEND_STK:
        valuePtr = OBJ_AT_TOS; /* value to append */
        part2Ptr = NULL;
        storeFlags = (TCL_LEAVE_ERR_MSG | TCL_APPEND_VALUE);
        goto doStoreStk;

    case INST_APPEND_ARRAY_STK:
        valuePtr = OBJ_AT_TOS; /* value to append */
        part2Ptr = OBJ_UNDER_TOS;
        storeFlags = (TCL_LEAVE_ERR_MSG | TCL_APPEND_VALUE);
        goto doStoreStk;

    case INST_STORE_ARRAY_STK:
        valuePtr = OBJ_AT_TOS;
        part2Ptr = OBJ_UNDER_TOS;
        storeFlags = TCL_LEAVE_ERR_MSG;
        goto doStoreStk;

    case INST_STORE_STK:
    case INST_STORE_SCALAR_STK:
        valuePtr = OBJ_AT_TOS;
        part2Ptr = NULL;
        storeFlags = TCL_LEAVE_ERR_MSG;

    doStoreStk:
        objPtr = OBJ_AT_DEPTH(1 + (part2Ptr != NULL)); /* variable name */
        part1Ptr = objPtr;
#ifdef TCL_COMPILE_DEBUG
        if (part2Ptr == NULL) {
            TRACE(("\"%.30s\" <- \"%.30s\" =>", O2S(part1Ptr),O2S(valuePtr)));
        } else {
            TRACE(("\"%.30s(%.30s)\" <- \"%.30s\" => ",
                    O2S(part1Ptr), O2S(part2Ptr), O2S(valuePtr)));
        }
#endif
        varPtr = TclObjLookupVarEx(interp, objPtr,part2Ptr, TCL_LEAVE_ERR_MSG,
                "set", /*createPart1*/ 1, /*createPart2*/ 1, &arrayPtr);
        if (varPtr) {
            cleanup = ((part2Ptr == NULL)? 2 : 3);
            pcAdjustment = 1;
            opnd = -1;
            goto doCallPtrSetVar;
        } else {
            TRACE_APPEND(("ERROR: %.30s\n", O2S(Tcl_GetObjResult(interp))));
            result = TCL_ERROR;
            goto checkForCatch;
        }

    case INST_LAPPEND_ARRAY4:
        opnd = TclGetUInt4AtPtr(pc+1);
        pcAdjustment = 5;
        storeFlags = (TCL_LEAVE_ERR_MSG | TCL_APPEND_VALUE
                | TCL_LIST_ELEMENT | TCL_TRACE_READS);
        goto doStoreArray;

    case INST_LAPPEND_ARRAY1:
        opnd = TclGetUInt1AtPtr(pc+1);
        pcAdjustment = 2;
        storeFlags = (TCL_LEAVE_ERR_MSG | TCL_APPEND_VALUE
                | TCL_LIST_ELEMENT | TCL_TRACE_READS);
        goto doStoreArray;

    case INST_APPEND_ARRAY4:
        opnd = TclGetUInt4AtPtr(pc+1);
        pcAdjustment = 5;
        storeFlags = (TCL_LEAVE_ERR_MSG | TCL_APPEND_VALUE);
        goto doStoreArray;

    case INST_APPEND_ARRAY1:
        opnd = TclGetUInt1AtPtr(pc+1);
        pcAdjustment = 2;
        storeFlags = (TCL_LEAVE_ERR_MSG | TCL_APPEND_VALUE);
        goto doStoreArray;

    doStoreArray:
        valuePtr = OBJ_AT_TOS;
        part2Ptr = OBJ_UNDER_TOS;
        arrayPtr = &(compiledLocals[opnd]);
        TRACE(("%u \"%.30s\" <- \"%.30s\" => ", opnd, O2S(part2Ptr),
                O2S(valuePtr)));
        while (TclIsVarLink(arrayPtr)) {
            arrayPtr = arrayPtr->value.linkPtr;
        }
        cleanup = 2;
        part1Ptr = NULL;

    doStoreArrayDirectFailed:
        varPtr = TclLookupArrayElement(interp, part1Ptr, part2Ptr,
                TCL_LEAVE_ERR_MSG, "set", 1, 1, arrayPtr, opnd);
        if (varPtr) {
            goto doCallPtrSetVar;
        } else {
            TRACE_APPEND(("ERROR: %.30s\n", O2S(Tcl_GetObjResult(interp))));
            result = TCL_ERROR;
            goto checkForCatch;
        }

    case INST_LAPPEND_SCALAR4:
        opnd = TclGetUInt4AtPtr(pc+1);
        pcAdjustment = 5;
        storeFlags = (TCL_LEAVE_ERR_MSG | TCL_APPEND_VALUE
                | TCL_LIST_ELEMENT | TCL_TRACE_READS);
        goto doStoreScalar;

    case INST_LAPPEND_SCALAR1:
        opnd = TclGetUInt1AtPtr(pc+1);
        pcAdjustment = 2;
        storeFlags = (TCL_LEAVE_ERR_MSG | TCL_APPEND_VALUE
                | TCL_LIST_ELEMENT | TCL_TRACE_READS);
        goto doStoreScalar;

    case INST_APPEND_SCALAR4:
        opnd = TclGetUInt4AtPtr(pc+1);
        pcAdjustment = 5;
        storeFlags = (TCL_LEAVE_ERR_MSG | TCL_APPEND_VALUE);
        goto doStoreScalar;

    case INST_APPEND_SCALAR1:
        opnd = TclGetUInt1AtPtr(pc+1);
        pcAdjustment = 2;
        storeFlags = (TCL_LEAVE_ERR_MSG | TCL_APPEND_VALUE);
        goto doStoreScalar;

    doStoreScalar:
        valuePtr = OBJ_AT_TOS;
        varPtr = &(compiledLocals[opnd]);
        TRACE(("%u <- \"%.30s\" => ", opnd, O2S(valuePtr)));
        while (TclIsVarLink(varPtr)) {
            varPtr = varPtr->value.linkPtr;
        }
        cleanup = 1;
        arrayPtr = NULL;
        part1Ptr = part2Ptr = NULL;

    doCallPtrSetVar:
        DECACHE_STACK_INFO();
        objResultPtr = TclPtrSetVar(interp, varPtr, arrayPtr,
                part1Ptr, part2Ptr, valuePtr, storeFlags, opnd);
        CACHE_STACK_INFO();
        if (objResultPtr) {
#ifndef TCL_COMPILE_DEBUG
            if (*(pc+pcAdjustment) == INST_POP) {
                NEXT_INST_V((pcAdjustment+1), cleanup, 0);
            }
#endif
            TRACE_APPEND(("%.30s\n", O2S(objResultPtr)));
            NEXT_INST_V(pcAdjustment, cleanup, 1);
        } else {
            TRACE_APPEND(("ERROR: %.30s\n", O2S(Tcl_GetObjResult(interp))));
            result = TCL_ERROR;
            goto checkForCatch;
        }
    }

    /*
     *     End of INST_STORE and related instructions.
     * ---------------------------------------------------------
     */

    /*
     * ---------------------------------------------------------
     *     Start of INST_INCR instructions.
     *
     * WARNING: more 'goto' here than your doctor recommended! The different
     * instructions set the value of some variables and then jump to somme
     * common execution code.
     */

/*TODO: Consider more untangling here; merge with LOAD and STORE ? */

    {
        Tcl_Obj *objPtr, *incrPtr;
        int opnd, pcAdjustment;
#ifndef NO_WIDE_TYPE
        Tcl_WideInt w;
#endif
        long i;
        Tcl_Obj *part1Ptr, *part2Ptr;
        Var *varPtr, *arrayPtr;

    case INST_INCR_SCALAR1:
    case INST_INCR_ARRAY1:
    case INST_INCR_ARRAY_STK:
    case INST_INCR_SCALAR_STK:
    case INST_INCR_STK:
        opnd = TclGetUInt1AtPtr(pc+1);
        incrPtr = POP_OBJECT();
        switch (*pc) {
        case INST_INCR_SCALAR1:
            pcAdjustment = 2;
            goto doIncrScalar;
        case INST_INCR_ARRAY1:
            pcAdjustment = 2;
            goto doIncrArray;
        default:
            pcAdjustment = 1;
            goto doIncrStk;
        }

    case INST_INCR_ARRAY_STK_IMM:
    case INST_INCR_SCALAR_STK_IMM:
    case INST_INCR_STK_IMM:
        i = TclGetInt1AtPtr(pc+1);
        incrPtr = Tcl_NewIntObj(i);
        Tcl_IncrRefCount(incrPtr);
        pcAdjustment = 2;

    doIncrStk:
        if ((*pc == INST_INCR_ARRAY_STK_IMM)
                || (*pc == INST_INCR_ARRAY_STK)) {
            part2Ptr = OBJ_AT_TOS;
            objPtr = OBJ_UNDER_TOS;
            TRACE(("\"%.30s(%.30s)\" (by %ld) => ",
                    O2S(objPtr), O2S(part2Ptr), i));
        } else {
            part2Ptr = NULL;
            objPtr = OBJ_AT_TOS;
            TRACE(("\"%.30s\" (by %ld) => ", O2S(objPtr), i));
        }
        part1Ptr = objPtr;
        opnd = -1;
        varPtr = TclObjLookupVarEx(interp, objPtr, part2Ptr,
                TCL_LEAVE_ERR_MSG, "read", 1, 1, &arrayPtr);
        if (varPtr) {
            cleanup = ((part2Ptr == NULL)? 1 : 2);
            goto doIncrVar;
        } else {
            Tcl_AddObjErrorInfo(interp,
                    "\n    (reading value of variable to increment)", -1);
            TRACE_APPEND(("ERROR: %.30s\n", O2S(Tcl_GetObjResult(interp))));
            result = TCL_ERROR;
            Tcl_DecrRefCount(incrPtr);
            goto checkForCatch;
        }

    case INST_INCR_ARRAY1_IMM:
        opnd = TclGetUInt1AtPtr(pc+1);
        i = TclGetInt1AtPtr(pc+2);
        incrPtr = Tcl_NewIntObj(i);
        Tcl_IncrRefCount(incrPtr);
        pcAdjustment = 3;

    doIncrArray:
        part1Ptr = NULL;
        part2Ptr = OBJ_AT_TOS;
        arrayPtr = &(compiledLocals[opnd]);
        cleanup = 1;
        while (TclIsVarLink(arrayPtr)) {
            arrayPtr = arrayPtr->value.linkPtr;
        }
        TRACE(("%u \"%.30s\" (by %ld) => ", opnd, O2S(part2Ptr), i));
        varPtr = TclLookupArrayElement(interp, part1Ptr, part2Ptr,
                TCL_LEAVE_ERR_MSG, "read", 1, 1, arrayPtr, opnd);
        if (varPtr) {
            goto doIncrVar;
        } else {
            TRACE_APPEND(("ERROR: %.30s\n", O2S(Tcl_GetObjResult(interp))));
            result = TCL_ERROR;
            Tcl_DecrRefCount(incrPtr);
            goto checkForCatch;
        }

    case INST_INCR_SCALAR1_IMM:
        opnd = TclGetUInt1AtPtr(pc+1);
        i = TclGetInt1AtPtr(pc+2);
        pcAdjustment = 3;
        cleanup = 0;
        varPtr = &(compiledLocals[opnd]);
        while (TclIsVarLink(varPtr)) {
            varPtr = varPtr->value.linkPtr;
        }

        if (TclIsVarDirectModifyable(varPtr)) {
            ClientData ptr;
            int type;

            objPtr = varPtr->value.objPtr;
            if (GetNumberFromObj(NULL, objPtr, &ptr, &type) == TCL_OK) {
                if (type == TCL_NUMBER_LONG) {
                    long augend = *((const long *)ptr);
                    long sum = augend + i;

                    /*
                     * Overflow when (augend and sum have different sign) and
                     * (augend and i have the same sign). This is encapsulated
                     * in the Overflowing macro.
                     */

                    if (!Overflowing(augend, i, sum)) {
                        TRACE(("%u %ld => ", opnd, i));
                        if (Tcl_IsShared(objPtr)) {
                            objPtr->refCount--; /* We know it's shared. */
                            TclNewLongObj(objResultPtr, sum);
                            Tcl_IncrRefCount(objResultPtr);
                            varPtr->value.objPtr = objResultPtr;
                        } else {
                            objResultPtr = objPtr;
                            TclSetLongObj(objPtr, sum);
                        }
                        goto doneIncr;
                    }
#ifndef NO_WIDE_TYPE
                    {
                        w = (Tcl_WideInt)augend;

                        TRACE(("%u %ld => ", opnd, i));
                        if (Tcl_IsShared(objPtr)) {
                            objPtr->refCount--; /* We know it's shared. */
                            objResultPtr = Tcl_NewWideIntObj(w+i);
                            Tcl_IncrRefCount(objResultPtr);
                            varPtr->value.objPtr = objResultPtr;
                        } else {
                            objResultPtr = objPtr;

                            /*
                             * We know the sum value is outside the long
                             * range; use macro form that doesn't range test
                             * again.
                             */

                            TclSetWideIntObj(objPtr, w+i);
                        }
                        goto doneIncr;
                    }
#endif
                }       /* end if (type == TCL_NUMBER_LONG) */
#ifndef NO_WIDE_TYPE
                if (type == TCL_NUMBER_WIDE) {
                    Tcl_WideInt sum;
                    w = *((const Tcl_WideInt *)ptr);
                    sum = w + i;

                    /*
                     * Check for overflow.
                     */

                    if (!Overflowing(w, i, sum)) {
                        TRACE(("%u %ld => ", opnd, i));
                        if (Tcl_IsShared(objPtr)) {
                            objPtr->refCount--; /* We know it's shared. */
                            objResultPtr = Tcl_NewWideIntObj(sum);
                            Tcl_IncrRefCount(objResultPtr);
                            varPtr->value.objPtr = objResultPtr;
                        } else {
                            objResultPtr = objPtr;

                            /*
                             * We *do not* know the sum value is outside the
                             * long range (wide + long can yield long); use
                             * the function call that checks range.
                             */

                            Tcl_SetWideIntObj(objPtr, sum);
                        }
                        goto doneIncr;
                    }
                }
#endif
            }
            if (Tcl_IsShared(objPtr)) {
                objPtr->refCount--;     /* We know it's shared */
                objResultPtr = Tcl_DuplicateObj(objPtr);
                Tcl_IncrRefCount(objResultPtr);
                varPtr->value.objPtr = objResultPtr;
            } else {
                objResultPtr = objPtr;
            }
            TclNewLongObj(incrPtr, i);
            result = TclIncrObj(interp, objResultPtr, incrPtr);
            Tcl_DecrRefCount(incrPtr);
            if (result == TCL_OK) {
                goto doneIncr;
            } else {
                TRACE_APPEND(("ERROR: %.30s\n",
                        O2S(Tcl_GetObjResult(interp))));
                goto checkForCatch;
            }
        }

        /*
         * All other cases, flow through to generic handling.
         */

        TclNewLongObj(incrPtr, i);
        Tcl_IncrRefCount(incrPtr);

    doIncrScalar:
        varPtr = &(compiledLocals[opnd]);
        while (TclIsVarLink(varPtr)) {
            varPtr = varPtr->value.linkPtr;
        }
        arrayPtr = NULL;
        part1Ptr = part2Ptr = NULL;
        cleanup = 0;
        TRACE(("%u %ld => ", opnd, i));

    doIncrVar:
        if (TclIsVarDirectModifyable2(varPtr, arrayPtr)) {
            objPtr = varPtr->value.objPtr;
            if (Tcl_IsShared(objPtr)) {
                objPtr->refCount--;     /* We know it's shared */
                objResultPtr = Tcl_DuplicateObj(objPtr);
                Tcl_IncrRefCount(objResultPtr);
                varPtr->value.objPtr = objResultPtr;
            } else {
                objResultPtr = objPtr;
            }
            result = TclIncrObj(interp, objResultPtr, incrPtr);
            Tcl_DecrRefCount(incrPtr);
            if (result == TCL_OK) {
                goto doneIncr;
            } else {
                TRACE_APPEND(("ERROR: %.30s\n",
                        O2S(Tcl_GetObjResult(interp))));
                goto checkForCatch;
            }
        } else {
            DECACHE_STACK_INFO();
            objResultPtr = TclPtrIncrObjVar(interp, varPtr, arrayPtr,
                    part1Ptr, part2Ptr, incrPtr, TCL_LEAVE_ERR_MSG, opnd);
            CACHE_STACK_INFO();
            Tcl_DecrRefCount(incrPtr);
            if (objResultPtr == NULL) {
                TRACE_APPEND(("ERROR: %.30s\n",
                        O2S(Tcl_GetObjResult(interp))));
                result = TCL_ERROR;
                goto checkForCatch;
            }
        }
    doneIncr:
        TRACE_APPEND(("%.30s\n", O2S(objResultPtr)));
#ifndef TCL_COMPILE_DEBUG
        if (*(pc+pcAdjustment) == INST_POP) {
            NEXT_INST_V((pcAdjustment+1), cleanup, 0);
        }
#endif
        NEXT_INST_V(pcAdjustment, cleanup, 1);
    }

    /*
     *     End of INST_INCR instructions.
     * ---------------------------------------------------------
     */

    /*
     * ---------------------------------------------------------
     *     Start of INST_EXIST instructions.
     */
    {
        Tcl_Obj *part1Ptr, *part2Ptr;
        Var *varPtr, *arrayPtr;

    case INST_EXIST_SCALAR: {
        int opnd = TclGetUInt4AtPtr(pc+1);

        varPtr = &(compiledLocals[opnd]);
        while (TclIsVarLink(varPtr)) {
            varPtr = varPtr->value.linkPtr;
        }
        TRACE(("%u => ", opnd));
        if (ReadTraced(varPtr)) {
            DECACHE_STACK_INFO();
            TclObjCallVarTraces(iPtr, NULL, varPtr, NULL, NULL,
                    TCL_TRACE_READS, 0, opnd);
            CACHE_STACK_INFO();
            if (TclIsVarUndefined(varPtr)) {
                TclCleanupVar(varPtr, NULL);
                varPtr = NULL;
            }
        }

        /*
         * Tricky! Arrays always exist.
         */

        objResultPtr = constants[!varPtr || TclIsVarUndefined(varPtr) ? 0 : 1];
        TRACE_APPEND(("%.30s\n", O2S(objResultPtr)));
        NEXT_INST_F(5, 0, 1);
    }

    case INST_EXIST_ARRAY: {
        int opnd = TclGetUInt4AtPtr(pc+1);

        part2Ptr = OBJ_AT_TOS;
        arrayPtr = &(compiledLocals[opnd]);
        while (TclIsVarLink(arrayPtr)) {
            arrayPtr = arrayPtr->value.linkPtr;
        }
        TRACE(("%u \"%.30s\" => ", opnd, O2S(part2Ptr)));
        if (TclIsVarArray(arrayPtr) && !ReadTraced(arrayPtr)) {
            varPtr = VarHashFindVar(arrayPtr->value.tablePtr, part2Ptr);
            if (!varPtr || !ReadTraced(varPtr)) {
                goto doneExistArray;
            }
        }
        varPtr = TclLookupArrayElement(interp, NULL, part2Ptr, 0, "access",
                0, 1, arrayPtr, opnd);
        if (varPtr) {
            if (ReadTraced(varPtr) || (arrayPtr && ReadTraced(arrayPtr))) {
                DECACHE_STACK_INFO();
                TclObjCallVarTraces(iPtr, arrayPtr, varPtr, NULL, part2Ptr,
                        TCL_TRACE_READS, 0, opnd);
                CACHE_STACK_INFO();
            }
            if (TclIsVarUndefined(varPtr)) {
                TclCleanupVar(varPtr, arrayPtr);
                varPtr = NULL;
            }
        }
    doneExistArray:
        objResultPtr = constants[!varPtr || TclIsVarUndefined(varPtr) ? 0 : 1];
        TRACE_APPEND(("%.30s\n", O2S(objResultPtr)));
        NEXT_INST_F(5, 1, 1);
    }

    case INST_EXIST_ARRAY_STK:
        cleanup = 2;
        part2Ptr = OBJ_AT_TOS;          /* element name */
        part1Ptr = OBJ_UNDER_TOS;       /* array name */
        TRACE(("\"%.30s(%.30s)\" => ", O2S(part1Ptr), O2S(part2Ptr)));
        goto doExistStk;

    case INST_EXIST_STK:
        cleanup = 1;
        part2Ptr = NULL;
        part1Ptr = OBJ_AT_TOS;          /* variable name */
        TRACE(("\"%.30s\" => ", O2S(part1Ptr)));

    doExistStk:
        varPtr = TclObjLookupVarEx(interp, part1Ptr, part2Ptr, 0, "access",
                /*createPart1*/0, /*createPart2*/1, &arrayPtr);
        if (varPtr) {
            if (ReadTraced(varPtr) || (arrayPtr && ReadTraced(arrayPtr))) {
                DECACHE_STACK_INFO();
                TclObjCallVarTraces(iPtr, arrayPtr, varPtr, part1Ptr,part2Ptr,
                        TCL_TRACE_READS, 0, -1);
                CACHE_STACK_INFO();
            }
            if (TclIsVarUndefined(varPtr)) {
                TclCleanupVar(varPtr, arrayPtr);
                varPtr = NULL;
            }
        }
        objResultPtr = constants[!varPtr || TclIsVarUndefined(varPtr) ? 0 : 1];
        TRACE_APPEND(("%.30s\n", O2S(objResultPtr)));
        NEXT_INST_V(1, cleanup, 1);
    }

    /*
     *     End of INST_EXIST instructions.
     * ---------------------------------------------------------
     */

    case INST_UPVAR: {
        int opnd;
        Var *varPtr, *otherPtr;

        TRACE_WITH_OBJ(("upvar "), OBJ_UNDER_TOS);

        {
            CallFrame *framePtr, *savedFramePtr;

            result = TclObjGetFrame(interp, OBJ_UNDER_TOS, &framePtr);
            if (result != -1) {
                /*
                 * Locate the other variable.
                 */

                savedFramePtr = iPtr->varFramePtr;
                iPtr->varFramePtr = framePtr;
                otherPtr = TclObjLookupVarEx(interp, OBJ_AT_TOS, NULL,
                        (TCL_LEAVE_ERR_MSG), "access",
                        /*createPart1*/ 1, /*createPart2*/ 1, &varPtr);
                iPtr->varFramePtr = savedFramePtr;
                if (otherPtr) {
                    result = TCL_OK;
                    goto doLinkVars;
                }
            }
            result = TCL_ERROR;
            goto checkForCatch;
        }

    case INST_VARIABLE:
        TRACE(("variable "));
        otherPtr = TclObjLookupVarEx(interp, OBJ_AT_TOS, NULL,
                (TCL_NAMESPACE_ONLY | TCL_LEAVE_ERR_MSG), "access",
                /*createPart1*/ 1, /*createPart2*/ 1, &varPtr);
        if (otherPtr) {
            /*
             * Do the [variable] magic.
             */

            TclSetVarNamespaceVar(otherPtr);
            result = TCL_OK;
            goto doLinkVars;
        }
        result = TCL_ERROR;
        goto checkForCatch;

    case INST_NSUPVAR:
        TRACE_WITH_OBJ(("nsupvar "), OBJ_UNDER_TOS);

        {
            Tcl_Namespace *nsPtr, *savedNsPtr;

            result = TclGetNamespaceFromObj(interp, OBJ_UNDER_TOS, &nsPtr);
            if (result == TCL_OK) {
                /*
                 * Locate the other variable.
                 */

                savedNsPtr = (Tcl_Namespace *) iPtr->varFramePtr->nsPtr;
                iPtr->varFramePtr->nsPtr = (Namespace *) nsPtr;
                otherPtr = TclObjLookupVarEx(interp, OBJ_AT_TOS, NULL,
                        (TCL_NAMESPACE_ONLY | TCL_LEAVE_ERR_MSG), "access",
                        /*createPart1*/ 1, /*createPart2*/ 1, &varPtr);
                iPtr->varFramePtr->nsPtr = (Namespace *) savedNsPtr;
                if (otherPtr) {
                    goto doLinkVars;
                }
            }
            result = TCL_ERROR;
            goto checkForCatch;
        }

    doLinkVars:

        /*
         * If we are here, the local variable has already been created: do the
         * little work of TclPtrMakeUpvar that remains to be done right here
         * if there are no errors; otherwise, let it handle the case.
         */

        opnd = TclGetInt4AtPtr(pc+1);;
        varPtr = &(compiledLocals[opnd]);
        if ((varPtr != otherPtr) && !TclIsVarTraced(varPtr)
                && (TclIsVarUndefined(varPtr) || TclIsVarLink(varPtr))) {
            if (!TclIsVarUndefined(varPtr)) {
                /*
                 * Then it is a defined link.
                 */

                Var *linkPtr = varPtr->value.linkPtr;

                if (linkPtr == otherPtr) {
                    goto doLinkVarsDone;
                }
                if (TclIsVarInHash(linkPtr)) {
                    VarHashRefCount(linkPtr)--;
                    if (TclIsVarUndefined(linkPtr)) {
                        TclCleanupVar(linkPtr, NULL);
                    }
                }
            }
            TclSetVarLink(varPtr);
            varPtr->value.linkPtr = otherPtr;
            if (TclIsVarInHash(otherPtr)) {
                VarHashRefCount(otherPtr)++;
            }
        } else {
            result = TclPtrObjMakeUpvar(interp, otherPtr, NULL, 0, opnd);
            if (result != TCL_OK) {
                goto checkForCatch;
            }
        }

        /*
         * Do not pop the namespace or frame index, it may be needed for other
         * variables - and [variable] did not push it at all.
         */

    doLinkVarsDone:
        NEXT_INST_F(5, 1, 0);
    }

    case INST_JUMP1: {
        int opnd = TclGetInt1AtPtr(pc+1);

        TRACE(("%d => new pc %u\n", opnd,
                (unsigned)(pc + opnd - codePtr->codeStart)));
        NEXT_INST_F(opnd, 0, 0);
    }

    case INST_JUMP4: {
        int opnd = TclGetInt4AtPtr(pc+1);

        TRACE(("%d => new pc %u\n", opnd,
                (unsigned)(pc + opnd - codePtr->codeStart)));
        NEXT_INST_F(opnd, 0, 0);
    }

    {
        int jmpOffset[2], b;
        Tcl_Obj *valuePtr;

        /* TODO: consider rewrite so we don't compute the offset we're not
         * going to take. */
    case INST_JUMP_FALSE4:
        jmpOffset[0] = TclGetInt4AtPtr(pc+1);   /* FALSE offset */
        jmpOffset[1] = 5;                       /* TRUE offset*/
        goto doCondJump;

    case INST_JUMP_TRUE4:
        jmpOffset[0] = 5;
        jmpOffset[1] = TclGetInt4AtPtr(pc+1);
        goto doCondJump;

    case INST_JUMP_FALSE1:
        jmpOffset[0] = TclGetInt1AtPtr(pc+1);
        jmpOffset[1] = 2;
        goto doCondJump;

    case INST_JUMP_TRUE1:
        jmpOffset[0] = 2;
        jmpOffset[1] = TclGetInt1AtPtr(pc+1);

    doCondJump:
        valuePtr = OBJ_AT_TOS;

        /* TODO - check claim that taking address of b harms performance */
        /* TODO - consider optimization search for constants */
        result = TclGetBooleanFromObj(interp, valuePtr, &b);
        if (result != TCL_OK) {
            TRACE_WITH_OBJ(("%d => ERROR: ", jmpOffset[
                    ((*pc == INST_JUMP_FALSE1) || (*pc == INST_JUMP_FALSE4))
                    ? 0 : 1]), Tcl_GetObjResult(interp));
            goto checkForCatch;
        }

#ifdef TCL_COMPILE_DEBUG
        if (b) {
            if ((*pc == INST_JUMP_TRUE1) || (*pc == INST_JUMP_TRUE4)) {
                TRACE(("%d => %.20s true, new pc %u\n", jmpOffset[1],
                        O2S(valuePtr),
                        (unsigned)(pc + jmpOffset[1] - codePtr->codeStart)));
            } else {
                TRACE(("%d => %.20s true\n", jmpOffset[0], O2S(valuePtr)));
            }
        } else {
            if ((*pc == INST_JUMP_TRUE1) || (*pc == INST_JUMP_TRUE4)) {
                TRACE(("%d => %.20s false\n", jmpOffset[0], O2S(valuePtr)));
            } else {
                TRACE(("%d => %.20s false, new pc %u\n", jmpOffset[0],
                        O2S(valuePtr),
                        (unsigned)(pc + jmpOffset[1] - codePtr->codeStart)));
            }
        }
#endif
        NEXT_INST_F(jmpOffset[b], 1, 0);
    }

    case INST_JUMP_TABLE: {
        Tcl_HashEntry *hPtr;
        JumptableInfo *jtPtr;
        int opnd;

        /*
         * Jump to location looked up in a hashtable; fall through to next
         * instr if lookup fails.
         */

        opnd = TclGetInt4AtPtr(pc+1);
        jtPtr = (JumptableInfo *) codePtr->auxDataArrayPtr[opnd].clientData;
        TRACE(("%d => %.20s ", opnd, O2S(OBJ_AT_TOS)));
        hPtr = Tcl_FindHashEntry(&jtPtr->hashTable, TclGetString(OBJ_AT_TOS));
        if (hPtr != NULL) {
            int jumpOffset = PTR2INT(Tcl_GetHashValue(hPtr));

            TRACE_APPEND(("found in table, new pc %u\n",
                    (unsigned)(pc - codePtr->codeStart + jumpOffset)));
            NEXT_INST_F(jumpOffset, 1, 0);
        } else {
            TRACE_APPEND(("not found in table\n"));
            NEXT_INST_F(5, 1, 0);
        }
    }

    /*
     * These two instructions are now redundant: the complete logic of the LOR
     * and LAND is now handled by the expression compiler.
     */

    case INST_LOR:
    case INST_LAND: {
        /*
         * Operands must be boolean or numeric. No int->double conversions are
         * performed.
         */

        int i1, i2, iResult;
        Tcl_Obj *value2Ptr = OBJ_AT_TOS;
        Tcl_Obj *valuePtr = OBJ_UNDER_TOS;

        result = TclGetBooleanFromObj(NULL, valuePtr, &i1);
        if (result != TCL_OK) {
            TRACE(("\"%.20s\" => ILLEGAL TYPE %s \n", O2S(valuePtr),
                    (valuePtr->typePtr? valuePtr->typePtr->name : "null")));
            IllegalExprOperandType(interp, pc, valuePtr);
            goto checkForCatch;
        }

        result = TclGetBooleanFromObj(NULL, value2Ptr, &i2);
        if (result != TCL_OK) {
            TRACE(("\"%.20s\" => ILLEGAL TYPE %s \n", O2S(value2Ptr),
                    (value2Ptr->typePtr? value2Ptr->typePtr->name : "null")));
            IllegalExprOperandType(interp, pc, value2Ptr);
            goto checkForCatch;
        }

        if (*pc == INST_LOR) {
            iResult = (i1 || i2);
        } else {
            iResult = (i1 && i2);
        }
        objResultPtr = constants[iResult];
        TRACE(("%.20s %.20s => %d\n", O2S(valuePtr),O2S(value2Ptr),iResult));
        NEXT_INST_F(1, 2, 1);
    }

    /*
     * ---------------------------------------------------------
     *     Start of INST_LIST and related instructions.
     */

    case INST_LIST: {
        /*
         * Pop the opnd (objc) top stack elements into a new list obj and then
         * decrement their ref counts.
         */

        int opnd;

        opnd = TclGetUInt4AtPtr(pc+1);
        objResultPtr = Tcl_NewListObj(opnd, &OBJ_AT_DEPTH(opnd-1));
        TRACE_WITH_OBJ(("%u => ", opnd), objResultPtr);
        NEXT_INST_V(5, opnd, 1);
    }

    case INST_LIST_LENGTH: {
        Tcl_Obj *valuePtr;
        int length;

        valuePtr = OBJ_AT_TOS;

        result = TclListObjLength(interp, valuePtr, &length);
        if (result == TCL_OK) {
            TclNewIntObj(objResultPtr, length);
            TRACE(("%.20s => %d\n", O2S(valuePtr), length));
            NEXT_INST_F(1, 1, 1);
        } else {
            TRACE_WITH_OBJ(("%.30s => ERROR: ", O2S(valuePtr)),
                    Tcl_GetObjResult(interp));
            goto checkForCatch;
        }
    }

    case INST_LIST_INDEX: {
        /*** lindex with objc == 3 ***/

        /* Variables also for INST_LIST_INDEX_IMM */

        int listc, idx, opnd, pcAdjustment;
        Tcl_Obj **listv;
        Tcl_Obj *valuePtr, *value2Ptr;

        /*
         * Pop the two operands.
         */

        value2Ptr = OBJ_AT_TOS;
        valuePtr = OBJ_UNDER_TOS;

        /*
         * Extract the desired list element.
         */

        result = TclListObjGetElements(interp, valuePtr, &listc, &listv);
        if ((result == TCL_OK) && (value2Ptr->typePtr != &tclListType)
                && (TclGetIntForIndexM(NULL , value2Ptr, listc-1,
                        &idx) == TCL_OK)) {
            TclDecrRefCount(value2Ptr);
            tosPtr--;
            pcAdjustment = 1;
            goto lindexFastPath;
        }

        objResultPtr = TclLindexList(interp, valuePtr, value2Ptr);
        if (objResultPtr) {
            /*
             * Stash the list element on the stack.
             */

            TRACE(("%.20s %.20s => %s\n",
                    O2S(valuePtr), O2S(value2Ptr), O2S(objResultPtr)));
            NEXT_INST_F(1, 2, -1);      /* Already has the correct refCount */
        } else {
            TRACE_WITH_OBJ(("%.30s %.30s => ERROR: ", O2S(valuePtr),
                    O2S(value2Ptr)), Tcl_GetObjResult(interp));
            result = TCL_ERROR;
            goto checkForCatch;
        }

    case INST_LIST_INDEX_IMM:
        /*** lindex with objc==3 and index in bytecode stream ***/

        pcAdjustment = 5;

        /*
         * Pop the list and get the index.
         */

        valuePtr = OBJ_AT_TOS;
        opnd = TclGetInt4AtPtr(pc+1);

        /*
         * Get the contents of the list, making sure that it really is a list
         * in the process.
         */

        result = TclListObjGetElements(interp, valuePtr, &listc, &listv);

        if (result == TCL_OK) {
            /*
             * Select the list item based on the index. Negative operand means
             * end-based indexing.
             */

            if (opnd < -1) {
                idx = opnd+1 + listc;
            } else {
                idx = opnd;
            }

        lindexFastPath:
            if (idx >= 0 && idx < listc) {
                objResultPtr = listv[idx];
            } else {
                TclNewObj(objResultPtr);
            }

            TRACE_WITH_OBJ(("\"%.30s\" %d => ", O2S(valuePtr), opnd),
                    objResultPtr);
            NEXT_INST_F(pcAdjustment, 1, 1);
        } else {
            TRACE_WITH_OBJ(("\"%.30s\" %d => ERROR: ", O2S(valuePtr), opnd),
                    Tcl_GetObjResult(interp));
            goto checkForCatch;
        }
    }

    case INST_LIST_INDEX_MULTI: {
        /*
         * 'lindex' with multiple index args:
         *
         * Determine the count of index args.
         */

        int numIdx, opnd;

        opnd = TclGetUInt4AtPtr(pc+1);
        numIdx = opnd-1;

        /*
         * Do the 'lindex' operation.
         */

        objResultPtr = TclLindexFlat(interp, OBJ_AT_DEPTH(numIdx),
                numIdx, &OBJ_AT_DEPTH(numIdx - 1));

        /*
         * Check for errors.
         */

        if (objResultPtr) {
            /*
             * Set result.
             */

            TRACE(("%d => %s\n", opnd, O2S(objResultPtr)));
            NEXT_INST_V(5, opnd, -1);
        } else {
            TRACE_WITH_OBJ(("%d => ERROR: ", opnd), Tcl_GetObjResult(interp));
            result = TCL_ERROR;
            goto checkForCatch;
        }
    }

    case INST_LSET_FLAT: {
        /*
         * Lset with 3, 5, or more args. Get the number of index args.
         */

        int numIdx,opnd;
        Tcl_Obj *valuePtr, *value2Ptr;

        opnd = TclGetUInt4AtPtr(pc + 1);
        numIdx = opnd - 2;

        /*
         * Get the old value of variable, and remove the stack ref. This is
         * safe because the variable still references the object; the ref
         * count will never go zero here - we can use the smaller macro
         * Tcl_DecrRefCount.
         */

        value2Ptr = POP_OBJECT();
        Tcl_DecrRefCount(value2Ptr); /* This one should be done here */

        /*
         * Get the new element value.
         */

        valuePtr = OBJ_AT_TOS;

        /*
         * Compute the new variable value.
         */

        objResultPtr = TclLsetFlat(interp, value2Ptr, numIdx,
                &OBJ_AT_DEPTH(numIdx), valuePtr);

        /*
         * Check for errors.
         */

        if (objResultPtr) {
            /*
             * Set result.
             */

            TRACE(("%d => %s\n", opnd, O2S(objResultPtr)));
            NEXT_INST_V(5, (numIdx+1), -1);
        } else {
            TRACE_WITH_OBJ(("%d => ERROR: ", opnd), Tcl_GetObjResult(interp));
            result = TCL_ERROR;
            goto checkForCatch;
        }
    }

    case INST_LSET_LIST: {
        /*
         * 'lset' with 4 args.
         */

        Tcl_Obj *objPtr, *valuePtr, *value2Ptr;

        /*
         * Get the old value of variable, and remove the stack ref. This is
         * safe because the variable still references the object; the ref
         * count will never go zero here - we can use the smaller macro
         * Tcl_DecrRefCount.
         */

        objPtr = POP_OBJECT();
        Tcl_DecrRefCount(objPtr);       /* This one should be done here. */

        /*
         * Get the new element value, and the index list.
         */

        valuePtr = OBJ_AT_TOS;
        value2Ptr = OBJ_UNDER_TOS;

        /*
         * Compute the new variable value.
         */

        objResultPtr = TclLsetList(interp, objPtr, value2Ptr, valuePtr);

        /*
         * Check for errors.
         */

        if (objResultPtr) {
            /*
             * Set result.
             */

            TRACE(("=> %s\n", O2S(objResultPtr)));
            NEXT_INST_F(1, 2, -1);
        } else {
            TRACE_WITH_OBJ(("\"%.30s\" => ERROR: ", O2S(value2Ptr)),
                    Tcl_GetObjResult(interp));
            result = TCL_ERROR;
            goto checkForCatch;
        }
    }

    case INST_LIST_RANGE_IMM: {
        /*** lrange with objc==4 and both indices in bytecode stream ***/

        int listc, fromIdx, toIdx;
        Tcl_Obj **listv, *valuePtr;

        /*
         * Pop the list and get the indices.
         */

        valuePtr = OBJ_AT_TOS;
        fromIdx = TclGetInt4AtPtr(pc+1);
        toIdx = TclGetInt4AtPtr(pc+5);

        /*
         * Get the contents of the list, making sure that it really is a list
         * in the process.
         */
        result = TclListObjGetElements(interp, valuePtr, &listc, &listv);

        /*
         * Skip a lot of work if we're about to throw the result away (common
         * with uses of [lassign]).
         */

        if (result == TCL_OK) {
#ifndef TCL_COMPILE_DEBUG
            if (*(pc+9) == INST_POP) {
                NEXT_INST_F(10, 1, 0);
            }
#endif
        } else {
            TRACE_WITH_OBJ(("\"%.30s\" %d %d => ERROR: ", O2S(valuePtr),
                    fromIdx, toIdx), Tcl_GetObjResult(interp));
            goto checkForCatch;
        }

        /*
         * Adjust the indices for end-based handling.
         */

        if (fromIdx < -1) {
            fromIdx += 1+listc;
            if (fromIdx < -1) {
                fromIdx = -1;
            }
        } else if (fromIdx > listc) {
            fromIdx = listc;
        }
        if (toIdx < -1) {
            toIdx += 1+listc;
            if (toIdx < -1) {
                toIdx = -1;
            }
        } else if (toIdx > listc) {
            toIdx = listc;
        }

        /*
         * Check if we are referring to a valid, non-empty list range, and if
         * so, build the list of elements in that range.
         */

        if (fromIdx<=toIdx && fromIdx<listc && toIdx>=0) {
            if (fromIdx<0) {
                fromIdx = 0;
            }
            if (toIdx >= listc) {
                toIdx = listc-1;
            }
            objResultPtr = Tcl_NewListObj(toIdx-fromIdx+1, listv+fromIdx);
        } else {
            TclNewObj(objResultPtr);
        }

        TRACE_WITH_OBJ(("\"%.30s\" %d %d => ", O2S(valuePtr),
                TclGetInt4AtPtr(pc+1), TclGetInt4AtPtr(pc+5)), objResultPtr);
        NEXT_INST_F(9, 1, 1);
    }

    case INST_LIST_IN:
    case INST_LIST_NOT_IN: {
        /*
         * Basic list containment operators.
         */

        int found, s1len, s2len, llen, i;
        Tcl_Obj *valuePtr, *value2Ptr, *o;
        char *s1;
        const char *s2;

        value2Ptr = OBJ_AT_TOS;
        valuePtr = OBJ_UNDER_TOS;

        /* TODO: Consider more efficient tests than strcmp() */
        s1 = TclGetStringFromObj(valuePtr, &s1len);
        result = TclListObjLength(interp, value2Ptr, &llen);
        if (result != TCL_OK) {
            TRACE_WITH_OBJ(("\"%.30s\" \"%.30s\" => ERROR: ", O2S(valuePtr),
                    O2S(value2Ptr)), Tcl_GetObjResult(interp));
            goto checkForCatch;
        }
        found = 0;
        if (llen > 0) {
            /*
             * An empty list doesn't match anything.
             */

            i = 0;
            do {
                Tcl_ListObjIndex(NULL, value2Ptr, i, &o);
                if (o != NULL) {
                    s2 = TclGetStringFromObj(o, &s2len);
                } else {
                    s2 = "";
                }
                if (s1len == s2len) {
                    found = (strcmp(s1, s2) == 0);
                }
                i++;
            } while (i < llen && found == 0);
        }

        if (*pc == INST_LIST_NOT_IN) {
            found = !found;
        }

        TRACE(("%.20s %.20s => %d\n", O2S(valuePtr), O2S(value2Ptr), found));

        /*
         * Peep-hole optimisation: if you're about to jump, do jump from here.
         * We're saving the effort of pushing a boolean value only to pop it
         * for branching.
         */

        pc++;
#ifndef TCL_COMPILE_DEBUG
        switch (*pc) {
        case INST_JUMP_FALSE1:
            NEXT_INST_F((found ? 2 : TclGetInt1AtPtr(pc+1)), 2, 0);
        case INST_JUMP_TRUE1:
            NEXT_INST_F((found ? TclGetInt1AtPtr(pc+1) : 2), 2, 0);
        case INST_JUMP_FALSE4:
            NEXT_INST_F((found ? 5 : TclGetInt4AtPtr(pc+1)), 2, 0);
        case INST_JUMP_TRUE4:
            NEXT_INST_F((found ? TclGetInt4AtPtr(pc+1) : 5), 2, 0);
        }
#endif
        objResultPtr = constants[found];
        NEXT_INST_F(0, 2, 1);
    }

    /*
     *     End of INST_LIST and related instructions.
     * ---------------------------------------------------------
     */

    case INST_STR_EQ:
    case INST_STR_NEQ: {
        /*
         * String (in)equality check
         * TODO: Consider merging into INST_STR_CMP
         */

        int iResult;
        Tcl_Obj *valuePtr, *value2Ptr;

        value2Ptr = OBJ_AT_TOS;
        valuePtr = OBJ_UNDER_TOS;

        if (valuePtr == value2Ptr) {
            /*
             * On the off-chance that the objects are the same, we don't
             * really have to think hard about equality.
             */

            iResult = (*pc == INST_STR_EQ);
        } else {
            char *s1, *s2;
            int s1len, s2len;

            s1 = TclGetStringFromObj(valuePtr, &s1len);
            s2 = TclGetStringFromObj(value2Ptr, &s2len);
            if (s1len == s2len) {
                /*
                 * We only need to check (in)equality when we have equal
                 * length strings.
                 */

                if (*pc == INST_STR_NEQ) {
                    iResult = (strcmp(s1, s2) != 0);
                } else {
                    /* INST_STR_EQ */
                    iResult = (strcmp(s1, s2) == 0);
                }
            } else {
                iResult = (*pc == INST_STR_NEQ);
            }
        }

        TRACE(("%.20s %.20s => %d\n", O2S(valuePtr),O2S(value2Ptr),iResult));

        /*
         * Peep-hole optimisation: if you're about to jump, do jump from here.
         */

        pc++;
#ifndef TCL_COMPILE_DEBUG
        switch (*pc) {
        case INST_JUMP_FALSE1:
            NEXT_INST_F((iResult? 2 : TclGetInt1AtPtr(pc+1)), 2, 0);
        case INST_JUMP_TRUE1:
            NEXT_INST_F((iResult? TclGetInt1AtPtr(pc+1) : 2), 2, 0);
        case INST_JUMP_FALSE4:
            NEXT_INST_F((iResult? 5 : TclGetInt4AtPtr(pc+1)), 2, 0);
        case INST_JUMP_TRUE4:
            NEXT_INST_F((iResult? TclGetInt4AtPtr(pc+1) : 5), 2, 0);
        }
#endif
        objResultPtr = constants[iResult];
        NEXT_INST_F(0, 2, 1);
    }

    case INST_STR_CMP: {
        /*
         * String compare.
         */

        const char *s1, *s2;
        int s1len, s2len, iResult;
        Tcl_Obj *valuePtr, *value2Ptr;

    stringCompare:
        value2Ptr = OBJ_AT_TOS;
        valuePtr = OBJ_UNDER_TOS;

        /*
         * The comparison function should compare up to the minimum byte
         * length only.
         */

        if (valuePtr == value2Ptr) {
            /*
             * In the pure equality case, set lengths too for the checks below
             * (or we could goto beyond it).
             */

            iResult = s1len = s2len = 0;
        } else if ((valuePtr->typePtr == &tclByteArrayType)
                && (value2Ptr->typePtr == &tclByteArrayType)) {
            s1 = (char *) Tcl_GetByteArrayFromObj(valuePtr, &s1len);
            s2 = (char *) Tcl_GetByteArrayFromObj(value2Ptr, &s2len);
            iResult = memcmp(s1, s2,
                    (size_t) ((s1len < s2len) ? s1len : s2len));
        } else if (((valuePtr->typePtr == &tclStringType)
                && (value2Ptr->typePtr == &tclStringType))) {
            /*
             * Do a unicode-specific comparison if both of the args are of
             * String type. If the char length == byte length, we can do a
             * memcmp. In benchmark testing this proved the most efficient
             * check between the unicode and string comparison operations.
             */

            s1len = Tcl_GetCharLength(valuePtr);
            s2len = Tcl_GetCharLength(value2Ptr);
            if ((s1len == valuePtr->length) && (s2len == value2Ptr->length)) {
                iResult = memcmp(valuePtr->bytes, value2Ptr->bytes,
                        (unsigned) ((s1len < s2len) ? s1len : s2len));
            } else {
                iResult = TclUniCharNcmp(Tcl_GetUnicode(valuePtr),
                        Tcl_GetUnicode(value2Ptr),
                        (unsigned) ((s1len < s2len) ? s1len : s2len));
            }
        } else {
            /*
             * We can't do a simple memcmp in order to handle the special Tcl
             * \xC0\x80 null encoding for utf-8.
             */

            s1 = TclGetStringFromObj(valuePtr, &s1len);
            s2 = TclGetStringFromObj(value2Ptr, &s2len);
            iResult = TclpUtfNcmp2(s1, s2,
                    (size_t) ((s1len < s2len) ? s1len : s2len));
        }

        /*
         * Make sure only -1,0,1 is returned
         * TODO: consider peephole opt.
         */

        if (iResult == 0) {
            iResult = s1len - s2len;
        }

        if (*pc != INST_STR_CMP) {
            /*
             * Take care of the opcodes that goto'ed into here.
             */

            switch (*pc) {
            case INST_EQ:
                iResult = (iResult == 0);
                break;
            case INST_NEQ:
                iResult = (iResult != 0);
                break;
            case INST_LT:
                iResult = (iResult < 0);
                break;
            case INST_GT:
                iResult = (iResult > 0);
                break;
            case INST_LE:
                iResult = (iResult <= 0);
                break;
            case INST_GE:
                iResult = (iResult >= 0);
                break;
            }
        }
        if (iResult < 0) {
            TclNewIntObj(objResultPtr, -1);
            TRACE(("%.20s %.20s => %d\n", O2S(valuePtr), O2S(value2Ptr), -1));
        } else {
            objResultPtr = constants[(iResult>0)];
            TRACE(("%.20s %.20s => %d\n", O2S(valuePtr), O2S(value2Ptr),
                (iResult > 0)));
        }

        NEXT_INST_F(1, 2, 1);
    }

    case INST_STR_LEN: {
        int length;
        Tcl_Obj *valuePtr;

        valuePtr = OBJ_AT_TOS;

        if (valuePtr->typePtr == &tclByteArrayType) {
            (void) Tcl_GetByteArrayFromObj(valuePtr, &length);
        } else {
            length = Tcl_GetCharLength(valuePtr);
        }
        TclNewIntObj(objResultPtr, length);
        TRACE(("%.20s => %d\n", O2S(valuePtr), length));
        NEXT_INST_F(1, 1, 1);
    }

    case INST_STR_INDEX: {
        /*
         * String compare.
         */

        int index, length;
        char *bytes;
        Tcl_Obj *valuePtr, *value2Ptr;

        bytes = NULL; /* lint */
        value2Ptr = OBJ_AT_TOS;
        valuePtr = OBJ_UNDER_TOS;

        /*
         * If we have a ByteArray object, avoid indexing in the Utf string
         * since the byte array contains one byte per character. Otherwise,
         * use the Unicode string rep to get the index'th char.
         */

        if (valuePtr->typePtr == &tclByteArrayType) {
            bytes = (char *)Tcl_GetByteArrayFromObj(valuePtr, &length);
        } else {
            /*
             * Get Unicode char length to calulate what 'end' means.
             */

            length = Tcl_GetCharLength(valuePtr);
        }

        result = TclGetIntForIndexM(interp, value2Ptr, length - 1, &index);
        if (result != TCL_OK) {
            goto checkForCatch;
        }

        if ((index >= 0) && (index < length)) {
            if (valuePtr->typePtr == &tclByteArrayType) {
                objResultPtr = Tcl_NewByteArrayObj((unsigned char *)
                        (&bytes[index]), 1);
            } else if (valuePtr->bytes && length == valuePtr->length) {
                objResultPtr = Tcl_NewStringObj((const char *)
                        (&valuePtr->bytes[index]), 1);
            } else {
                char buf[TCL_UTF_MAX];
                Tcl_UniChar ch;

                ch = Tcl_GetUniChar(valuePtr, index);

                /*
                 * This could be: Tcl_NewUnicodeObj((const Tcl_UniChar *)&ch,
                 * 1) but creating the object as a string seems to be faster
                 * in practical use.
                 */

                length = Tcl_UniCharToUtf(ch, buf);
                objResultPtr = Tcl_NewStringObj(buf, length);
            }
        } else {
            TclNewObj(objResultPtr);
        }

        TRACE(("%.20s %.20s => %s\n", O2S(valuePtr), O2S(value2Ptr),
                O2S(objResultPtr)));
        NEXT_INST_F(1, 2, 1);
    }

    case INST_STR_MATCH: {
        int nocase, match;
        Tcl_Obj *valuePtr, *value2Ptr;

        nocase = TclGetInt1AtPtr(pc+1);
        valuePtr = OBJ_AT_TOS;          /* String */
        value2Ptr = OBJ_UNDER_TOS;      /* Pattern */

        /*
         * Check that at least one of the objects is Unicode before promoting
         * both.
         */

        if ((valuePtr->typePtr == &tclStringType)
                || (value2Ptr->typePtr == &tclStringType)) {
            Tcl_UniChar *ustring1, *ustring2;
            int length1, length2;

            ustring1 = Tcl_GetUnicodeFromObj(valuePtr, &length1);
            ustring2 = Tcl_GetUnicodeFromObj(value2Ptr, &length2);
            match = TclUniCharMatch(ustring1, length1, ustring2, length2,
                    nocase);
        } else if ((valuePtr->typePtr == &tclByteArrayType) && !nocase) {
            unsigned char *string1, *string2;
            int length1, length2;

            string1 = Tcl_GetByteArrayFromObj(valuePtr, &length1);
            string2 = Tcl_GetByteArrayFromObj(value2Ptr, &length2);
            match = TclByteArrayMatch(string1, length1, string2, length2, 0);
        } else {
            match = Tcl_StringCaseMatch(TclGetString(valuePtr),
                    TclGetString(value2Ptr), nocase);
        }

        /*
         * Reuse value2Ptr object already on stack if possible. Adjustment is
         * 2 due to the nocase byte
         * TODO: consider peephole opt.
         */

        TRACE(("%.20s %.20s => %d\n", O2S(valuePtr), O2S(value2Ptr), match));
        objResultPtr = constants[match];
        NEXT_INST_F(2, 2, 1);
    }

    case INST_REGEXP: {
        int cflags, match;
        Tcl_Obj *valuePtr, *value2Ptr;
        Tcl_RegExp regExpr;

        cflags = TclGetInt1AtPtr(pc+1); /* RE compile flages like NOCASE */
        valuePtr = OBJ_AT_TOS;          /* String */
        value2Ptr = OBJ_UNDER_TOS;      /* Pattern */

        regExpr = Tcl_GetRegExpFromObj(interp, value2Ptr, cflags);
        if (regExpr == NULL) {
            match = -1;
        } else {
            match = Tcl_RegExpExecObj(interp, regExpr, valuePtr, 0, 0, 0);
        }

        /*
         * Adjustment is 2 due to the nocase byte
         */

        if (match < 0) {
            objResultPtr = Tcl_GetObjResult(interp);
            TRACE_WITH_OBJ(("%.20s %.20s => ERROR: ",
                    O2S(valuePtr), O2S(value2Ptr)), objResultPtr);
            result = TCL_ERROR;
            goto checkForCatch;
        } else {
            TRACE(("%.20s %.20s => %d\n",
                    O2S(valuePtr), O2S(value2Ptr), match));
            objResultPtr = constants[match];
            NEXT_INST_F(2, 2, 1);
        }
    }

    case INST_EQ:
    case INST_NEQ:
    case INST_LT:
    case INST_GT:
    case INST_LE:
    case INST_GE: {
        Tcl_Obj *valuePtr = OBJ_UNDER_TOS;
        Tcl_Obj *value2Ptr = OBJ_AT_TOS;
        ClientData ptr1, ptr2;
        int iResult = 0, compare = 0, type1, type2;
        double d1, d2, tmp;
        long l1, l2;
        mp_int big1, big2;
#ifndef NO_WIDE_TYPE
        Tcl_WideInt w1, w2;
#endif

        if (GetNumberFromObj(NULL, valuePtr, &ptr1, &type1) != TCL_OK) {
            /*
             * At least one non-numeric argument - compare as strings.
             */

            goto stringCompare;
        }
        if (type1 == TCL_NUMBER_NAN) {
            /*
             * NaN first arg: NaN != to everything, other compares are false.
             */

            iResult = (*pc == INST_NEQ);
            goto foundResult;
        }
        if (valuePtr == value2Ptr) {
            compare = MP_EQ;
            goto convertComparison;
        }
        if (GetNumberFromObj(NULL, value2Ptr, &ptr2, &type2) != TCL_OK) {
            /*
             * At least one non-numeric argument - compare as strings.
             */

            goto stringCompare;
        }
        if (type2 == TCL_NUMBER_NAN) {
            /*
             * NaN 2nd arg: NaN != to everything, other compares are false.
             */

            iResult = (*pc == INST_NEQ);
            goto foundResult;
        }
        switch (type1) {
        case TCL_NUMBER_LONG:
            l1 = *((const long *)ptr1);
            switch (type2) {
            case TCL_NUMBER_LONG:
                l2 = *((const long *)ptr2);
            longCompare:
                compare = (l1 < l2) ? MP_LT : ((l1 > l2) ? MP_GT : MP_EQ);
                break;
#ifndef NO_WIDE_TYPE
            case TCL_NUMBER_WIDE:
                w2 = *((const Tcl_WideInt *)ptr2);
                w1 = (Tcl_WideInt)l1;
                goto wideCompare;
#endif
            case TCL_NUMBER_DOUBLE:
                d2 = *((const double *)ptr2);
                d1 = (double) l1;

                /*
                 * If the double has a fractional part, or if the long can be
                 * converted to double without loss of precision, then compare
                 * as doubles.
                 */

                if (DBL_MANT_DIG > CHAR_BIT*sizeof(long)
                        || l1 == (long) d1
                        || modf(d2, &tmp) != 0.0) {
                    goto doubleCompare;
                }

                /*
                 * Otherwise, to make comparision based on full precision,
                 * need to convert the double to a suitably sized integer.
                 *
                 * Need this to get comparsions like
                 *      expr 20000000000000003 < 20000000000000004.0
                 * right. Converting the first argument to double will yield
                 * two double values that are equivalent within double
                 * precision. Converting the double to an integer gets done
                 * exactly, then integer comparison can tell the difference.
                 */

                if (d2 < (double)LONG_MIN) {
                    compare = MP_GT;
                    break;
                }
                if (d2 > (double)LONG_MAX) {
                    compare = MP_LT;
                    break;
                }
                l2 = (long) d2;
                goto longCompare;
            case TCL_NUMBER_BIG:
                Tcl_TakeBignumFromObj(NULL, value2Ptr, &big2);
                if (mp_cmp_d(&big2, 0) == MP_LT) {
                    compare = MP_GT;
                } else {
                    compare = MP_LT;
                }
                mp_clear(&big2);
            }
            break;

#ifndef NO_WIDE_TYPE
        case TCL_NUMBER_WIDE:
            w1 = *((const Tcl_WideInt *)ptr1);
            switch (type2) {
            case TCL_NUMBER_WIDE:
                w2 = *((const Tcl_WideInt *)ptr2);
            wideCompare:
                compare = (w1 < w2) ? MP_LT : ((w1 > w2) ? MP_GT : MP_EQ);
                break;
            case TCL_NUMBER_LONG:
                l2 = *((const long *)ptr2);
                w2 = (Tcl_WideInt)l2;
                goto wideCompare;
            case TCL_NUMBER_DOUBLE:
                d2 = *((const double *)ptr2);
                d1 = (double) w1;
                if (DBL_MANT_DIG > CHAR_BIT*sizeof(Tcl_WideInt)
                        || w1 == (Tcl_WideInt) d1
                        || modf(d2, &tmp) != 0.0) {
                    goto doubleCompare;
                }
                if (d2 < (double)LLONG_MIN) {
                    compare = MP_GT;
                    break;
                }
                if (d2 > (double)LLONG_MAX) {
                    compare = MP_LT;
                    break;
                }
                w2 = (Tcl_WideInt) d2;
                goto wideCompare;
            case TCL_NUMBER_BIG:
                Tcl_TakeBignumFromObj(NULL, value2Ptr, &big2);
                if (mp_cmp_d(&big2, 0) == MP_LT) {
                    compare = MP_GT;
                } else {
                    compare = MP_LT;
                }
                mp_clear(&big2);
            }
            break;
#endif

        case TCL_NUMBER_DOUBLE:
            d1 = *((const double *)ptr1);
            switch (type2) {
            case TCL_NUMBER_DOUBLE:
                d2 = *((const double *)ptr2);
            doubleCompare:
                compare = (d1 < d2) ? MP_LT : ((d1 > d2) ? MP_GT : MP_EQ);
                break;
            case TCL_NUMBER_LONG:
                l2 = *((const long *)ptr2);
                d2 = (double) l2;
                if (DBL_MANT_DIG > CHAR_BIT*sizeof(long)
                        || l2 == (long) d2
                        || modf(d1, &tmp) != 0.0) {
                    goto doubleCompare;
                }
                if (d1 < (double)LONG_MIN) {
                    compare = MP_LT;
                    break;
                }
                if (d1 > (double)LONG_MAX) {
                    compare = MP_GT;
                    break;
                }
                l1 = (long) d1;
                goto longCompare;
#ifndef NO_WIDE_TYPE
            case TCL_NUMBER_WIDE:
                w2 = *((const Tcl_WideInt *)ptr2);
                d2 = (double) w2;
                if (DBL_MANT_DIG > CHAR_BIT*sizeof(Tcl_WideInt)
                        || w2 == (Tcl_WideInt) d2
                        || modf(d1, &tmp) != 0.0) {
                    goto doubleCompare;
                }
                if (d1 < (double)LLONG_MIN) {
                    compare = MP_LT;
                    break;
                }
                if (d1 > (double)LLONG_MAX) {
                    compare = MP_GT;
                    break;
                }
                w1 = (Tcl_WideInt) d1;
                goto wideCompare;
#endif
            case TCL_NUMBER_BIG:
                if (TclIsInfinite(d1)) {
                    compare = (d1 > 0.0) ? MP_GT : MP_LT;
                    break;
                }
                Tcl_TakeBignumFromObj(NULL, value2Ptr, &big2);
                if ((d1 < (double)LONG_MAX) && (d1 > (double)LONG_MIN)) {
                    if (mp_cmp_d(&big2, 0) == MP_LT) {
                        compare = MP_GT;
                    } else {
                        compare = MP_LT;
                    }
                    mp_clear(&big2);
                    break;
                }
                if (DBL_MANT_DIG > CHAR_BIT*sizeof(long)
                        && modf(d1, &tmp) != 0.0) {
                    d2 = TclBignumToDouble(&big2);
                    mp_clear(&big2);
                    goto doubleCompare;
                }
                Tcl_InitBignumFromDouble(NULL, d1, &big1);
                goto bigCompare;
            }
            break;

        case TCL_NUMBER_BIG:
            Tcl_TakeBignumFromObj(NULL, valuePtr, &big1);
            switch (type2) {
#ifndef NO_WIDE_TYPE
            case TCL_NUMBER_WIDE:
#endif
            case TCL_NUMBER_LONG:
                compare = mp_cmp_d(&big1, 0);
                mp_clear(&big1);
                break;
            case TCL_NUMBER_DOUBLE:
                d2 = *((const double *)ptr2);
                if (TclIsInfinite(d2)) {
                    compare = (d2 > 0.0) ? MP_LT : MP_GT;
                    mp_clear(&big1);
                    break;
                }
                if ((d2 < (double)LONG_MAX) && (d2 > (double)LONG_MIN)) {
                    compare = mp_cmp_d(&big1, 0);
                    mp_clear(&big1);
                    break;
                }
                if (DBL_MANT_DIG > CHAR_BIT*sizeof(long)
                        && modf(d2, &tmp) != 0.0) {
                    d1 = TclBignumToDouble(&big1);
                    mp_clear(&big1);
                    goto doubleCompare;
                }
                Tcl_InitBignumFromDouble(NULL, d2, &big2);
                goto bigCompare;
            case TCL_NUMBER_BIG:
                Tcl_TakeBignumFromObj(NULL, value2Ptr, &big2);
            bigCompare:
                compare = mp_cmp(&big1, &big2);
                mp_clear(&big1);
                mp_clear(&big2);
            }
        }

        /*
         * Turn comparison outcome into appropriate result for opcode.
         */

    convertComparison:
        switch (*pc) {
        case INST_EQ:
            iResult = (compare == MP_EQ);
            break;
        case INST_NEQ:
            iResult = (compare != MP_EQ);
            break;
        case INST_LT:
            iResult = (compare == MP_LT);
            break;
        case INST_GT:
            iResult = (compare == MP_GT);
            break;
        case INST_LE:
            iResult = (compare != MP_GT);
            break;
        case INST_GE:
            iResult = (compare != MP_LT);
            break;
        }

        /*
         * Peep-hole optimisation: if you're about to jump, do jump from here.
         */

    foundResult:
        pc++;
#ifndef TCL_COMPILE_DEBUG
        switch (*pc) {
        case INST_JUMP_FALSE1:
            NEXT_INST_F((iResult? 2 : TclGetInt1AtPtr(pc+1)), 2, 0);
        case INST_JUMP_TRUE1:
            NEXT_INST_F((iResult? TclGetInt1AtPtr(pc+1) : 2), 2, 0);
        case INST_JUMP_FALSE4:
            NEXT_INST_F((iResult? 5 : TclGetInt4AtPtr(pc+1)), 2, 0);
        case INST_JUMP_TRUE4:
            NEXT_INST_F((iResult? TclGetInt4AtPtr(pc+1) : 5), 2, 0);
        }
#endif
        objResultPtr = constants[iResult];
        NEXT_INST_F(0, 2, 1);
    }

    case INST_MOD:
    case INST_LSHIFT:
    case INST_RSHIFT: {
        Tcl_Obj *value2Ptr = OBJ_AT_TOS;
        Tcl_Obj *valuePtr = OBJ_UNDER_TOS;
        ClientData ptr1, ptr2;
        int invalid, shift, type1, type2;
        long l1 = 0;

        result = GetNumberFromObj(NULL, valuePtr, &ptr1, &type1);
        if ((result != TCL_OK) || (type1 == TCL_NUMBER_DOUBLE)
                || (type1 == TCL_NUMBER_NAN)) {
            result = TCL_ERROR;
            TRACE(("%.20s %.20s => ILLEGAL 1st TYPE %s\n", O2S(valuePtr),
                    O2S(value2Ptr), (valuePtr->typePtr?
                    valuePtr->typePtr->name : "null")));
            IllegalExprOperandType(interp, pc, valuePtr);
            goto checkForCatch;
        }

        result = GetNumberFromObj(NULL, value2Ptr, &ptr2, &type2);
        if ((result != TCL_OK) || (type2 == TCL_NUMBER_DOUBLE)
                || (type2 == TCL_NUMBER_NAN)) {
            result = TCL_ERROR;
            TRACE(("%.20s %.20s => ILLEGAL 2nd TYPE %s\n", O2S(valuePtr),
                    O2S(value2Ptr), (value2Ptr->typePtr?
                    value2Ptr->typePtr->name : "null")));
            IllegalExprOperandType(interp, pc, value2Ptr);
            goto checkForCatch;
        }

        if (*pc == INST_MOD) {
            /* TODO: Attempts to re-use unshared operands on stack */

            long l2 = 0;        /* silence gcc warning */

            if (type2 == TCL_NUMBER_LONG) {
                l2 = *((const long *)ptr2);
                if (l2 == 0) {
                    TRACE(("%s %s => DIVIDE BY ZERO\n", O2S(valuePtr),
                            O2S(value2Ptr)));
                    goto divideByZero;
                }
                if ((l2 == 1) || (l2 == -1)) {
                    /*
                     * Div. by |1| always yields remainder of 0.
                     */

                    objResultPtr = constants[0];
                    TRACE(("%s\n", O2S(objResultPtr)));
                    NEXT_INST_F(1, 2, 1);
                }
            }
            if (type1 == TCL_NUMBER_LONG) {
                l1 = *((const long *)ptr1);
                if (l1 == 0) {
                    /*
                     * 0 % (non-zero) always yields remainder of 0.
                     */

                    objResultPtr = constants[0];
                    TRACE(("%s\n", O2S(objResultPtr)));
                    NEXT_INST_F(1, 2, 1);
                }
                if (type2 == TCL_NUMBER_LONG) {
                    /*
                     * Both operands are long; do native calculation.
                     */

                    long lRemainder, lQuotient = l1 / l2;

                    /*
                     * Force Tcl's integer division rules.
                     * TODO: examine for logic simplification
                     */

                    if ((lQuotient < 0 || (lQuotient == 0 &&
                            ((l1 < 0 && l2 > 0) || (l1 > 0 && l2 < 0)))) &&
                            (lQuotient * l2 != l1)) {
                        lQuotient -= 1;
                    }
                    lRemainder = l1 - l2*lQuotient;
                    TclNewLongObj(objResultPtr, lRemainder);
                    TRACE(("%s\n", O2S(objResultPtr)));
                    NEXT_INST_F(1, 2, 1);
                }

                /*
                 * First operand fits in long; second does not, so the second
                 * has greater magnitude than first. No need to divide to
                 * determine the remainder.
                 */

#ifndef NO_WIDE_TYPE
                if (type2 == TCL_NUMBER_WIDE) {
                    Tcl_WideInt w2 = *((const Tcl_WideInt *)ptr2);

                    if ((l1 > 0) ^ (w2 > (Tcl_WideInt)0)) {
                        /*
                         * Arguments are opposite sign; remainder is sum.
                         */

                        objResultPtr = Tcl_NewWideIntObj(w2+(Tcl_WideInt)l1);
                        TRACE(("%s\n", O2S(objResultPtr)));
                        NEXT_INST_F(1, 2, 1);
                    }

                    /*
                     * Arguments are same sign; remainder is first operand.
                     */

                    TRACE(("%s\n", O2S(valuePtr)));
                    NEXT_INST_F(1, 1, 0);
                }
#endif
                {
                    mp_int big2;

                    Tcl_TakeBignumFromObj(NULL, value2Ptr, &big2);

                    /* TODO: internals intrusion */
                    if ((l1 > 0) ^ (big2.sign == MP_ZPOS)) {
                        /*
                         * Arguments are opposite sign; remainder is sum.
                         */

                        mp_int big1;

                        TclBNInitBignumFromLong(&big1, l1);
                        mp_add(&big2, &big1, &big2);
                        mp_clear(&big1);
                        objResultPtr = Tcl_NewBignumObj(&big2);
                        TRACE(("%s\n", O2S(objResultPtr)));
                        NEXT_INST_F(1, 2, 1);
                    }

                    /*
                     * Arguments are same sign; remainder is first operand.
                     */

                    mp_clear(&big2);
                    TRACE(("%s\n", O2S(valuePtr)));
                    NEXT_INST_F(1, 1, 0);
                }
            }
#ifndef NO_WIDE_TYPE
            if (type1 == TCL_NUMBER_WIDE) {
                Tcl_WideInt w1 = *((const Tcl_WideInt *)ptr1);

                if (type2 != TCL_NUMBER_BIG) {
                    Tcl_WideInt w2, wQuotient, wRemainder;

                    Tcl_GetWideIntFromObj(NULL, value2Ptr, &w2);
                    wQuotient = w1 / w2;

                    /*
                     * Force Tcl's integer division rules.
                     * TODO: examine for logic simplification
                     */

                    if (((wQuotient < (Tcl_WideInt) 0)
                            || ((wQuotient == (Tcl_WideInt) 0)
                            && ((w1 < (Tcl_WideInt)0 && w2 > (Tcl_WideInt)0)
                            || (w1 > (Tcl_WideInt)0 && w2 < (Tcl_WideInt)0))))
                            && (wQuotient * w2 != w1)) {
                        wQuotient -= (Tcl_WideInt) 1;
                    }
                    wRemainder = w1 - w2*wQuotient;
                    objResultPtr = Tcl_NewWideIntObj(wRemainder);
                    TRACE(("%s\n", O2S(objResultPtr)));
                    NEXT_INST_F(1, 2, 1);
                }
                {
                    mp_int big2;
                    Tcl_TakeBignumFromObj(NULL, value2Ptr, &big2);

                    /* TODO: internals intrusion */
                    if ((w1 > ((Tcl_WideInt) 0)) ^ (big2.sign == MP_ZPOS)) {
                        /*
                         * Arguments are opposite sign; remainder is sum.
                         */

                        mp_int big1;

                        TclBNInitBignumFromWideInt(&big1, w1);
                        mp_add(&big2, &big1, &big2);
                        mp_clear(&big1);
                        objResultPtr = Tcl_NewBignumObj(&big2);
                        TRACE(("%s\n", O2S(objResultPtr)));
                        NEXT_INST_F(1, 2, 1);
                    }

                    /*
                     * Arguments are same sign; remainder is first operand.
                     */

                    mp_clear(&big2);
                    TRACE(("%s\n", O2S(valuePtr)));
                    NEXT_INST_F(1, 1, 0);
                }
            }
#endif
            {
                mp_int big1, big2, bigResult, bigRemainder;

                Tcl_GetBignumFromObj(NULL, valuePtr, &big1);
                Tcl_GetBignumFromObj(NULL, value2Ptr, &big2);
                mp_init(&bigResult);
                mp_init(&bigRemainder);
                mp_div(&big1, &big2, &bigResult, &bigRemainder);
                if (!mp_iszero(&bigRemainder)
                        && (bigRemainder.sign != big2.sign)) {
                    /*
                     * Convert to Tcl's integer division rules.
                     */

                    mp_sub_d(&bigResult, 1, &bigResult);
                    mp_add(&bigRemainder, &big2, &bigRemainder);
                }
                mp_copy(&bigRemainder, &bigResult);
                mp_clear(&bigRemainder);
                mp_clear(&big1);
                mp_clear(&big2);
                TRACE(("%s %s => ", O2S(valuePtr), O2S(value2Ptr)));
                if (Tcl_IsShared(valuePtr)) {
                    objResultPtr = Tcl_NewBignumObj(&bigResult);
                    TRACE(("%s\n", O2S(objResultPtr)));
                    NEXT_INST_F(1, 2, 1);
                }
                Tcl_SetBignumObj(valuePtr, &bigResult);
                TRACE(("%s\n", O2S(valuePtr)));
                NEXT_INST_F(1, 1, 0);
            }
        }

        /*
         * Reject negative shift argument.
         */

        switch (type2) {
        case TCL_NUMBER_LONG:
            invalid = (*((const long *)ptr2) < (long)0);
            break;
#ifndef NO_WIDE_TYPE
        case TCL_NUMBER_WIDE:
            invalid = (*((const Tcl_WideInt *)ptr2) < (Tcl_WideInt)0);
            break;
#endif
        case TCL_NUMBER_BIG: {
            mp_int big2;

            Tcl_TakeBignumFromObj(NULL, value2Ptr, &big2);
            invalid = (mp_cmp_d(&big2, 0) == MP_LT);
            mp_clear(&big2);
            break;
        }
        default:
            /* Unused, here to silence compiler warning */
            invalid = 0;
        }
        if (invalid) {
            Tcl_SetObjResult(interp,
                    Tcl_NewStringObj("negative shift argument", -1));
            result = TCL_ERROR;
            goto checkForCatch;
        }

        /*
         * Zero shifted any number of bits is still zero.
         */

        if ((type1==TCL_NUMBER_LONG) && (*((const long *)ptr1) == (long)0)) {
            TRACE(("%s %s => ", O2S(valuePtr), O2S(value2Ptr)));
            objResultPtr = constants[0];
            TRACE(("%s\n", O2S(objResultPtr)));
            NEXT_INST_F(1, 2, 1);
        }

        if (*pc == INST_LSHIFT) {
            /*
             * Large left shifts create integer overflow.
             *
             * BEWARE! Can't use Tcl_GetIntFromObj() here because that
             * converts values in the (unsigned) range to their signed int
             * counterparts, leading to incorrect results.
             */

            if ((type2 != TCL_NUMBER_LONG)
                    || (*((const long *)ptr2) > (long) INT_MAX)) {
                /*
                 * Technically, we could hold the value (1 << (INT_MAX+1)) in
                 * an mp_int, but since we're using mp_mul_2d() to do the
                 * work, and it takes only an int argument, that's a good
                 * place to draw the line.
                 */

                Tcl_SetObjResult(interp, Tcl_NewStringObj(
                        "integer value too large to represent", -1));
                result = TCL_ERROR;
                goto checkForCatch;
            }
            shift = (int)(*((const long *)ptr2));

            /*
             * Handle shifts within the native long range.
             */

            TRACE(("%s %s => ", O2S(valuePtr), O2S(value2Ptr)));
            if ((type1 == TCL_NUMBER_LONG)
                    && (size_t) shift < CHAR_BIT*sizeof(long)
                    && ((l1 = *(const long *)ptr1) != 0)
                    && !((l1>0 ? l1 : ~l1)
                            & -(1L<<(CHAR_BIT*sizeof(long) - 1 - shift)))) {
                TclNewLongObj(objResultPtr, (l1<<shift));
                TRACE(("%s\n", O2S(objResultPtr)));
                NEXT_INST_F(1, 2, 1);
            }

            /*
             * Handle shifts within the native wide range.
             */

            TRACE(("%s %s => ", O2S(valuePtr), O2S(value2Ptr)));
            if ((type1 != TCL_NUMBER_BIG)
                    && ((size_t)shift < CHAR_BIT*sizeof(Tcl_WideInt))) {
                Tcl_WideInt w;

                TclGetWideIntFromObj(NULL, valuePtr, &w);
                if (!((w>0 ? w : ~w)
                        & -(((Tcl_WideInt)1)
                        << (CHAR_BIT*sizeof(Tcl_WideInt) - 1 - shift)))) {
                    objResultPtr = Tcl_NewWideIntObj(w<<shift);
                    TRACE(("%s\n", O2S(objResultPtr)));
                    NEXT_INST_F(1, 2, 1);
                }
            }
        } else {
            /*
             * Quickly force large right shifts to 0 or -1.
             */

            TRACE(("%s %s => ", O2S(valuePtr), O2S(value2Ptr)));
            if ((type2 != TCL_NUMBER_LONG)
                    || (*(const long *)ptr2 > INT_MAX)) {
                /*
                 * Again, technically, the value to be shifted could be an
                 * mp_int so huge that a right shift by (INT_MAX+1) bits could
                 * not take us to the result of 0 or -1, but since we're using
                 * mp_div_2d to do the work, and it takes only an int
                 * argument, we draw the line there.
                 */

                int zero;

                switch (type1) {
                case TCL_NUMBER_LONG:
                    zero = (*(const long *)ptr1 > 0L);
                    break;
#ifndef NO_WIDE_TYPE
                case TCL_NUMBER_WIDE:
                    zero = (*(const Tcl_WideInt *)ptr1 > (Tcl_WideInt)0);
                    break;
#endif
                case TCL_NUMBER_BIG: {
                    mp_int big1;
                    Tcl_TakeBignumFromObj(NULL, valuePtr, &big1);
                    zero = (mp_cmp_d(&big1, 0) == MP_GT);
                    mp_clear(&big1);
                    break;
                }
                default:
                    /* Unused, here to silence compiler warning. */
                    zero = 0;
                }
                if (zero) {
                    objResultPtr = constants[0];
                } else {
                    TclNewIntObj(objResultPtr, -1);
                }
                TRACE(("%s\n", O2S(objResultPtr)));
                NEXT_INST_F(1, 2, 1);
            }
            shift = (int)(*(const long *)ptr2);

            /*
             * Handle shifts within the native long range.
             */

            if (type1 == TCL_NUMBER_LONG) {
                l1 = *((const long *)ptr1);
                if ((size_t)shift >= CHAR_BIT*sizeof(long)) {
                    if (l1 >= (long)0) {
                        objResultPtr = constants[0];
                    } else {
                        TclNewIntObj(objResultPtr, -1);
                    }
                } else {
                    TclNewLongObj(objResultPtr, (l1 >> shift));
                }
                TRACE(("%s\n", O2S(objResultPtr)));
                NEXT_INST_F(1, 2, 1);
            }

#ifndef NO_WIDE_TYPE
            /*
             * Handle shifts within the native wide range.
             */

            if (type1 == TCL_NUMBER_WIDE) {
                Tcl_WideInt w = *(const Tcl_WideInt *)ptr1;

                if ((size_t)shift >= CHAR_BIT*sizeof(Tcl_WideInt)) {
                    if (w >= (Tcl_WideInt)0) {
                        objResultPtr = constants[0];
                    } else {
                        TclNewIntObj(objResultPtr, -1);
                    }
                } else {
                    objResultPtr = Tcl_NewWideIntObj(w >> shift);
                }
                TRACE(("%s\n", O2S(objResultPtr)));
                NEXT_INST_F(1, 2, 1);
            }
#endif
        }

        {
            mp_int big, bigResult, bigRemainder;

            Tcl_TakeBignumFromObj(NULL, valuePtr, &big);

            mp_init(&bigResult);
            if (*pc == INST_LSHIFT) {
                mp_mul_2d(&big, shift, &bigResult);
            } else {
                mp_init(&bigRemainder);
                mp_div_2d(&big, shift, &bigResult, &bigRemainder);
                if (mp_cmp_d(&bigRemainder, 0) == MP_LT) {
                    /*
                     * Convert to Tcl's integer division rules.
                     */

                    mp_sub_d(&bigResult, 1, &bigResult);
                }
                mp_clear(&bigRemainder);
            }
            mp_clear(&big);

            if (!Tcl_IsShared(valuePtr)) {
                Tcl_SetBignumObj(valuePtr, &bigResult);
                TRACE(("%s\n", O2S(valuePtr)));
                NEXT_INST_F(1, 1, 0);
            }
            objResultPtr = Tcl_NewBignumObj(&bigResult);
        }
        TRACE(("%s\n", O2S(objResultPtr)));
        NEXT_INST_F(1, 2, 1);
    }

    case INST_BITOR:
    case INST_BITXOR:
    case INST_BITAND: {
        ClientData ptr1, ptr2;
        int type1, type2;
        Tcl_Obj *value2Ptr = OBJ_AT_TOS;
        Tcl_Obj *valuePtr = OBJ_UNDER_TOS;

        result = GetNumberFromObj(NULL, valuePtr, &ptr1, &type1);
        if ((result != TCL_OK)
                || (type1 == TCL_NUMBER_NAN)
                || (type1 == TCL_NUMBER_DOUBLE)) {
            result = TCL_ERROR;
            TRACE(("%.20s %.20s => ILLEGAL 1st TYPE %s\n", O2S(valuePtr),
                    O2S(value2Ptr), (valuePtr->typePtr?
                    valuePtr->typePtr->name : "null")));
            IllegalExprOperandType(interp, pc, valuePtr);
            goto checkForCatch;
        }
        result = GetNumberFromObj(NULL, value2Ptr, &ptr2, &type2);
        if ((result != TCL_OK) || (type2 == TCL_NUMBER_NAN)
                || (type2 == TCL_NUMBER_DOUBLE)) {
            result = TCL_ERROR;
            TRACE(("%.20s %.20s => ILLEGAL 2nd TYPE %s\n", O2S(valuePtr),
                    O2S(value2Ptr), (value2Ptr->typePtr?
                    value2Ptr->typePtr->name : "null")));
            IllegalExprOperandType(interp, pc, value2Ptr);
            goto checkForCatch;
        }

        if ((type1 == TCL_NUMBER_BIG) || (type2 == TCL_NUMBER_BIG)) {
            mp_int big1, big2, bigResult, *First, *Second;
            int numPos;

            Tcl_TakeBignumFromObj(NULL, valuePtr, &big1);
            Tcl_TakeBignumFromObj(NULL, value2Ptr, &big2);

            /*
             * Count how many positive arguments we have. If only one of the
             * arguments is negative, store it in 'Second'.
             */

            if (mp_cmp_d(&big1, 0) != MP_LT) {
                numPos = 1 + (mp_cmp_d(&big2, 0) != MP_LT);
                First = &big1;
                Second = &big2;
            } else {
                First = &big2;
                Second = &big1;
                numPos = (mp_cmp_d(First, 0) != MP_LT);
            }
            mp_init(&bigResult);

            switch (*pc) {
            case INST_BITAND:
                switch (numPos) {
                case 2:
                    /*
                     * Both arguments positive, base case.
                     */

                    mp_and(First, Second, &bigResult);
                    break;
                case 1:
                    /*
                     * First is positive; second negative:
                     * P & N = P & ~~N = P&~(-N-1) = P & (P ^ (-N-1))
                     */

                    mp_neg(Second, Second);
                    mp_sub_d(Second, 1, Second);
                    mp_xor(First, Second, &bigResult);
                    mp_and(First, &bigResult, &bigResult);
                    break;
                case 0:
                    /*
                     * Both arguments negative:
                     * a & b = ~ (~a | ~b) = -(-a-1|-b-1)-1
                     */

                    mp_neg(First, First);
                    mp_sub_d(First, 1, First);
                    mp_neg(Second, Second);
                    mp_sub_d(Second, 1, Second);
                    mp_or(First, Second, &bigResult);
                    mp_neg(&bigResult, &bigResult);
                    mp_sub_d(&bigResult, 1, &bigResult);
                    break;
                }
                break;

            case INST_BITOR:
                switch (numPos) {
                case 2:
                    /*
                     * Both arguments positive, base case.
                     */

                    mp_or(First, Second, &bigResult);
                    break;
                case 1:
                    /*
                     * First is positive; second negative:
                     * N|P = ~(~N&~P) = ~((-N-1)&~P) = -((-N-1)&((-N-1)^P))-1
                     */

                    mp_neg(Second, Second);
                    mp_sub_d(Second, 1, Second);
                    mp_xor(First, Second, &bigResult);
                    mp_and(Second, &bigResult, &bigResult);
                    mp_neg(&bigResult, &bigResult);
                    mp_sub_d(&bigResult, 1, &bigResult);
                    break;
                case 0:
                    /*
                     * Both arguments negative:
                     * a | b = ~ (~a & ~b) = -(-a-1&-b-1)-1
                     */

                    mp_neg(First, First);
                    mp_sub_d(First, 1, First);
                    mp_neg(Second, Second);
                    mp_sub_d(Second, 1, Second);
                    mp_and(First, Second, &bigResult);
                    mp_neg(&bigResult, &bigResult);
                    mp_sub_d(&bigResult, 1, &bigResult);
                    break;
                }
                break;

            case INST_BITXOR:
                switch (numPos) {
                case 2:
                    /*
                     * Both arguments positive, base case.
                     */

                    mp_xor(First, Second, &bigResult);
                    break;
                case 1:
                    /*
                     * First is positive; second negative:
                     * P^N = ~(P^~N) = -(P^(-N-1))-1
                     */

                    mp_neg(Second, Second);
                    mp_sub_d(Second, 1, Second);
                    mp_xor(First, Second, &bigResult);
                    mp_neg(&bigResult, &bigResult);
                    mp_sub_d(&bigResult, 1, &bigResult);
                    break;
                case 0:
                    /*
                     * Both arguments negative:
                     * a ^ b = (~a ^ ~b) = (-a-1^-b-1)
                     */

                    mp_neg(First, First);
                    mp_sub_d(First, 1, First);
                    mp_neg(Second, Second);
                    mp_sub_d(Second, 1, Second);
                    mp_xor(First, Second, &bigResult);
                    break;
                }
                break;
            }

            mp_clear(&big1);
            mp_clear(&big2);
            TRACE(("%s %s => ", O2S(valuePtr), O2S(value2Ptr)));
            if (Tcl_IsShared(valuePtr)) {
                objResultPtr = Tcl_NewBignumObj(&bigResult);
                TRACE(("%s\n", O2S(objResultPtr)));
                NEXT_INST_F(1, 2, 1);
            }
            Tcl_SetBignumObj(valuePtr, &bigResult);
            TRACE(("%s\n", O2S(valuePtr)));
            NEXT_INST_F(1, 1, 0);
        }

#ifndef NO_WIDE_TYPE
        if ((type1 == TCL_NUMBER_WIDE) || (type2 == TCL_NUMBER_WIDE)) {
            Tcl_WideInt wResult, w1, w2;

            TclGetWideIntFromObj(NULL, valuePtr, &w1);
            TclGetWideIntFromObj(NULL, value2Ptr, &w2);

            switch (*pc) {
            case INST_BITAND:
                wResult = w1 & w2;
                break;
            case INST_BITOR:
                wResult = w1 | w2;
                break;
            case INST_BITXOR:
                wResult = w1 ^ w2;
                break;
            default:
                /* Unused, here to silence compiler warning. */
                wResult = 0;
            }

            TRACE(("%s %s => ", O2S(valuePtr), O2S(value2Ptr)));
            if (Tcl_IsShared(valuePtr)) {
                objResultPtr = Tcl_NewWideIntObj(wResult);
                TRACE(("%s\n", O2S(objResultPtr)));
                NEXT_INST_F(1, 2, 1);
            }
            Tcl_SetWideIntObj(valuePtr, wResult);
            TRACE(("%s\n", O2S(valuePtr)));
            NEXT_INST_F(1, 1, 0);
        }
#endif
        {
            long lResult, l1 = *((const long *)ptr1);
            long l2 = *((const long *)ptr2);

            switch (*pc) {
            case INST_BITAND:
                lResult = l1 & l2;
                break;
            case INST_BITOR:
                lResult = l1 | l2;
                break;
            case INST_BITXOR:
                lResult = l1 ^ l2;
                break;
            default:
                /* Unused, here to silence compiler warning. */
                lResult = 0;
            }

            TRACE(("%s %s => ", O2S(valuePtr), O2S(value2Ptr)));
            if (Tcl_IsShared(valuePtr)) {
                TclNewLongObj(objResultPtr, lResult);
                TRACE(("%s\n", O2S(objResultPtr)));
                NEXT_INST_F(1, 2, 1);
            }
            TclSetLongObj(valuePtr, lResult);
            TRACE(("%s\n", O2S(valuePtr)));
            NEXT_INST_F(1, 1, 0);
        }
    }

    case INST_EXPON:
    case INST_ADD:
    case INST_SUB:
    case INST_DIV:
    case INST_MULT: {
        ClientData ptr1, ptr2;
        int type1, type2;
        Tcl_Obj *value2Ptr = OBJ_AT_TOS;
        Tcl_Obj *valuePtr = OBJ_UNDER_TOS;

        result = GetNumberFromObj(NULL, valuePtr, &ptr1, &type1);
        if ((result != TCL_OK)
#ifndef ACCEPT_NAN
                || (type1 == TCL_NUMBER_NAN)
#endif
                ) {
            result = TCL_ERROR;
            TRACE(("%.20s %.20s => ILLEGAL 1st TYPE %s\n",
                    O2S(value2Ptr), O2S(valuePtr),
                    (valuePtr->typePtr? valuePtr->typePtr->name: "null")));
            IllegalExprOperandType(interp, pc, valuePtr);
            goto checkForCatch;
        }

#ifdef ACCEPT_NAN
        if (type1 == TCL_NUMBER_NAN) {
            /*
             * NaN first argument -> result is also NaN.
             */

            NEXT_INST_F(1, 1, 0);
        }
#endif

        result = GetNumberFromObj(NULL, value2Ptr, &ptr2, &type2);
        if ((result != TCL_OK)
#ifndef ACCEPT_NAN
                || (type2 == TCL_NUMBER_NAN)
#endif
                ) {
            result = TCL_ERROR;
            TRACE(("%.20s %.20s => ILLEGAL 2nd TYPE %s\n",
                    O2S(value2Ptr), O2S(valuePtr),
                    (value2Ptr->typePtr? value2Ptr->typePtr->name: "null")));
            IllegalExprOperandType(interp, pc, value2Ptr);
            goto checkForCatch;
        }

#ifdef ACCEPT_NAN
        if (type2 == TCL_NUMBER_NAN) {
            /*
             * NaN second argument -> result is also NaN.
             */

            objResultPtr = value2Ptr;
            NEXT_INST_F(1, 2, 1);
        }
#endif

        if ((type1 == TCL_NUMBER_DOUBLE) || (type2 == TCL_NUMBER_DOUBLE)) {
            /*
             * At least one of the values is floating-point, so perform
             * floating point calculations.
             */

            double d1, d2, dResult;

            Tcl_GetDoubleFromObj(NULL, valuePtr, &d1);
            Tcl_GetDoubleFromObj(NULL, value2Ptr, &d2);

            switch (*pc) {
            case INST_ADD:
                dResult = d1 + d2;
                break;
            case INST_SUB:
                dResult = d1 - d2;
                break;
            case INST_MULT:
                dResult = d1 * d2;
                break;
            case INST_DIV:
#ifndef IEEE_FLOATING_POINT
                if (d2 == 0.0) {
                    TRACE(("%.6g %.6g => DIVIDE BY ZERO\n", d1, d2));
                    goto divideByZero;
                }
#endif
                /*
                 * We presume that we are running with zero-divide unmasked if
                 * we're on an IEEE box. Otherwise, this statement might cause
                 * demons to fly out our noses.
                 */

                dResult = d1 / d2;
                break;
            case INST_EXPON:
                if (d1==0.0 && d2<0.0) {
                    TRACE(("%.6g %.6g => EXPONENT OF ZERO\n", d1, d2));
                    goto exponOfZero;
                }
                dResult = pow(d1, d2);
                break;
            default:
                /* Unused, here to silence compiler warning. */
                dResult = 0;
            }

#ifndef ACCEPT_NAN
            /*
             * Check now for IEEE floating-point error.
             */

            if (TclIsNaN(dResult)) {
                TRACE(("%.20s %.20s => IEEE FLOATING PT ERROR\n",
                        O2S(valuePtr), O2S(value2Ptr)));
                TclExprFloatError(interp, dResult);
                result = TCL_ERROR;
                goto checkForCatch;
            }
#endif
            TRACE(("%s %s => ", O2S(valuePtr), O2S(value2Ptr)));
            if (Tcl_IsShared(valuePtr)) {
                TclNewDoubleObj(objResultPtr, dResult);
                TRACE(("%s\n", O2S(objResultPtr)));
                NEXT_INST_F(1, 2, 1);
            }
            TclSetDoubleObj(valuePtr, dResult);
            TRACE(("%s\n", O2S(valuePtr)));
            NEXT_INST_F(1, 1, 0);
        }

        if ((sizeof(long) >= 2*sizeof(int)) && (*pc == INST_MULT)
                && (type1 == TCL_NUMBER_LONG) && (type2 == TCL_NUMBER_LONG)) {
            long l1 = *((const long *)ptr1);
            long l2 = *((const long *)ptr2);

            if ((l1 <= INT_MAX) && (l1 >= INT_MIN)
                    && (l2 <= INT_MAX) && (l2 >= INT_MIN)) {
                long lResult = l1 * l2;

                TRACE(("%s %s => ", O2S(valuePtr), O2S(value2Ptr)));
                if (Tcl_IsShared(valuePtr)) {
                    TclNewLongObj(objResultPtr,lResult);
                    TRACE(("%s\n", O2S(objResultPtr)));
                    NEXT_INST_F(1, 2, 1);
                }
                TclSetLongObj(valuePtr, lResult);
                TRACE(("%s\n", O2S(valuePtr)));
                NEXT_INST_F(1, 1, 0);
            }
        }

        if ((sizeof(Tcl_WideInt) >= 2*sizeof(long)) && (*pc == INST_MULT)
                && (type1 == TCL_NUMBER_LONG) && (type2 == TCL_NUMBER_LONG)) {
            Tcl_WideInt w1, w2, wResult;
            TclGetWideIntFromObj(NULL, valuePtr, &w1);
            TclGetWideIntFromObj(NULL, value2Ptr, &w2);

            wResult = w1 * w2;

            TRACE(("%s %s => ", O2S(valuePtr), O2S(value2Ptr)));
            if (Tcl_IsShared(valuePtr)) {
                objResultPtr = Tcl_NewWideIntObj(wResult);
                TRACE(("%s\n", O2S(objResultPtr)));
                NEXT_INST_F(1, 2, 1);
            }
            Tcl_SetWideIntObj(valuePtr, wResult);
            TRACE(("%s\n", O2S(valuePtr)));
            NEXT_INST_F(1, 1, 0);
        }

        /* TODO: Attempts to re-use unshared operands on stack. */
        if (*pc == INST_EXPON) {
            long l1 = 0, l2 = 0;
            Tcl_WideInt w1;
            int oddExponent = 0, negativeExponent = 0;

            if (type2 == TCL_NUMBER_LONG) {
                l2 = *((const long *) ptr2);
                if (l2 == 0) {
                    /*
                     * Anything to the zero power is 1.
                     */

                    objResultPtr = constants[1];
                    NEXT_INST_F(1, 2, 1);
                } else if (l2 == 1) {
                    /*
                     * Anything to the first power is itself
                     */
                    NEXT_INST_F(1, 1, 0);
                }
            }

            switch (type2) {
            case TCL_NUMBER_LONG: {
                negativeExponent = (l2 < 0);
                oddExponent = (int) (l2 & 1);
                break;
            }
#ifndef NO_WIDE_TYPE
            case TCL_NUMBER_WIDE: {
                Tcl_WideInt w2 = *((const Tcl_WideInt *)ptr2);

                negativeExponent = (w2 < 0);
                oddExponent = (int) (w2 & (Tcl_WideInt)1);
                break;
            }
#endif
            case TCL_NUMBER_BIG: {
                mp_int big2;

                Tcl_TakeBignumFromObj(NULL, value2Ptr, &big2);
                negativeExponent = (mp_cmp_d(&big2, 0) == MP_LT);
                mp_mod_2d(&big2, 1, &big2);
                oddExponent = !mp_iszero(&big2);
                mp_clear(&big2);
                break;
            }
            }

            if (negativeExponent) {
                if (type1 == TCL_NUMBER_LONG) {
                    l1 = *((const long *)ptr1);
                    switch (l1) {
                    case 0:
                        /*
                         * Zero to a negative power is div by zero error.
                         */

                        TRACE(("%s %s => EXPONENT OF ZERO\n", O2S(valuePtr),
                                O2S(value2Ptr)));
                        goto exponOfZero;
                    case -1:
                        if (oddExponent) {
                            TclNewIntObj(objResultPtr, -1);
                        } else {
                            objResultPtr = constants[1];
                        }
                        NEXT_INST_F(1, 2, 1);
                    case 1:
                        /*
                         * 1 to any power is 1.
                         */

                        objResultPtr = constants[1];
                        NEXT_INST_F(1, 2, 1);
                    }
                }

                /*
                 * Integers with magnitude greater than 1 raise to a negative
                 * power yield the answer zero (see TIP 123).
                 */

                objResultPtr = constants[0];
                NEXT_INST_F(1, 2, 1);
            }

            if (type1 == TCL_NUMBER_LONG) {
                l1 = *((const long *)ptr1);
                switch (l1) {
                case 0:
                    /*
                     * Zero to a positive power is zero.
                     */

                    objResultPtr = constants[0];
                    NEXT_INST_F(1, 2, 1);
                case 1:
                    /*
                     * 1 to any power is 1.
                     */

                    objResultPtr = constants[1];
                    NEXT_INST_F(1, 2, 1);
                case -1:
                    if (oddExponent) {
                        TclNewIntObj(objResultPtr, -1);
                    } else {
                        objResultPtr = constants[1];
                    }
                    NEXT_INST_F(1, 2, 1);
                }
            }
            if (type2 == TCL_NUMBER_BIG) {
                Tcl_SetObjResult(interp,
                        Tcl_NewStringObj("exponent too large", -1));
                result = TCL_ERROR;
                goto checkForCatch;
            }

            if (type1 == TCL_NUMBER_LONG && type2 == TCL_NUMBER_LONG) {
                if (l1 == 2) {
                    /*
                     * Reduce small powers of 2 to shifts.
                     */

                    if ((unsigned long) l2 < CHAR_BIT * sizeof(long) - 1) {
                        TRACE(("%s %s => ", O2S(valuePtr), O2S(value2Ptr)));
                        TclNewLongObj(objResultPtr, (1L << l2));
                        TRACE(("%s\n", O2S(objResultPtr)));
                        NEXT_INST_F(1, 2, 1);
                    }
#if !defined(TCL_WIDE_INT_IS_LONG)
                    if ((unsigned long)l2 < CHAR_BIT*sizeof(Tcl_WideInt) - 1){
                        TRACE(("%s %s => ", O2S(valuePtr), O2S(value2Ptr)));
                        objResultPtr =
                                Tcl_NewWideIntObj(((Tcl_WideInt) 1) << l2);
                        TRACE(("%s\n", O2S(objResultPtr)));
                        NEXT_INST_F(1, 2, 1);
                    }
#endif
                }
                if (l1 == -2) {
                    int signum = oddExponent ? -1 : 1;

                    /*
                     * Reduce small powers of 2 to shifts.
                     */

                    if ((unsigned long) l2 < CHAR_BIT * sizeof(long) - 1) {
                        TRACE(("%s %s => ", O2S(valuePtr), O2S(value2Ptr)));
                        TclNewLongObj(objResultPtr, signum * (1L << l2));
                        TRACE(("%s\n", O2S(objResultPtr)));
                        NEXT_INST_F(1, 2, 1);
                    }
#if !defined(TCL_WIDE_INT_IS_LONG)
                    if ((unsigned long)l2 < CHAR_BIT*sizeof(Tcl_WideInt) - 1){
                        TRACE(("%s %s => ", O2S(valuePtr), O2S(value2Ptr)));
                        objResultPtr = Tcl_NewWideIntObj(
                                signum * (((Tcl_WideInt) 1) << l2));
                        TRACE(("%s\n", O2S(objResultPtr)));
                        NEXT_INST_F(1, 2, 1);
                    }
#endif
                }
#if (LONG_MAX == 0x7fffffff)
                if (l2 <= 8 &&
                        l1 <= MaxBase32[l2-2] && l1 >= -MaxBase32[l2-2]) {
                    /*
                     * Small powers of 32-bit integers.
                     */

                    long lResult = l1 * l1;     /* b**2 */
                    switch (l2) {
                    case 2:
                        break;
                    case 3:
                        lResult *= l1;          /* b**3 */
                        break;
                    case 4:
                        lResult *= lResult;     /* b**4 */
                        break;
                    case 5:
                        lResult *= lResult;     /* b**4 */
                        lResult *= l1;          /* b**5 */
                        break;
                    case 6:
                        lResult *= l1;          /* b**3 */
                        lResult *= lResult;     /* b**6 */
                        break;
                    case 7:
                        lResult *= l1;          /* b**3 */
                        lResult *= lResult;     /* b**6 */
                        lResult *= l1;          /* b**7 */
                        break;
                    case 8:
                        lResult *= lResult;     /* b**4 */
                        lResult *= lResult;     /* b**8 */
                        break;
                    }
                    TRACE(("%s %s => ", O2S(valuePtr), O2S(value2Ptr)));
                    if (Tcl_IsShared(valuePtr)) {
                        TclNewLongObj(objResultPtr, lResult);
                        TRACE(("%s\n", O2S(objResultPtr)));
                        NEXT_INST_F(1, 2, 1);
                    }
                    Tcl_SetLongObj(valuePtr, lResult);
                    TRACE(("%s\n", O2S(valuePtr)));
                    NEXT_INST_F(1, 1, 0);
                }
                if (l1 >= 3 &&
                        ((unsigned long) l1 < (sizeof(Exp32Index)
                                / sizeof(unsigned short)) - 1)) {
                    unsigned short base = Exp32Index[l1-3]
                            + (unsigned short) l2 - 9;
                    if (base < Exp32Index[l1-2]) {
                        /*
                         * 32-bit number raised to intermediate power, done by
                         * table lookup.
                         */

                        TRACE(("%s %s => ", O2S(valuePtr), O2S(value2Ptr)));
                        if (Tcl_IsShared(valuePtr)) {
                            TclNewLongObj(objResultPtr, Exp32Value[base]);
                            TRACE(("%s\n", O2S(objResultPtr)));
                            NEXT_INST_F(1, 2, 1);
                        }
                        Tcl_SetLongObj(valuePtr, Exp32Value[base]);
                        TRACE(("%s\n", O2S(valuePtr)));
                        NEXT_INST_F(1, 1, 0);
                    }
                }
                if (-l1 >= 3
                    && (unsigned long)(-l1) < (sizeof(Exp32Index)
                             / sizeof(unsigned short)) - 1) {
                    unsigned short base
                        = Exp32Index[-l1-3] + (unsigned short) l2 - 9;
                    if (base < Exp32Index[-l1-2]) {
                        long lResult = (oddExponent) ?
                            -Exp32Value[base] : Exp32Value[base];

                        /*
                         * 32-bit number raised to intermediate power, done by
                         * table lookup.
                         */

                        TRACE(("%s %s => ", O2S(valuePtr), O2S(value2Ptr)));
                        if (Tcl_IsShared(valuePtr)) {
                            TclNewLongObj(objResultPtr, lResult);
                            TRACE(("%s\n", O2S(objResultPtr)));
                            NEXT_INST_F(1, 2, 1);
                        }
                        Tcl_SetLongObj(valuePtr, lResult);
                        TRACE(("%s\n", O2S(valuePtr)));
                        NEXT_INST_F(1, 1, 0);
                    }
                }
#endif
            }
            if (type1 == TCL_NUMBER_LONG) {
                w1 = l1;
#ifndef NO_WIDE_TYPE
            } else if (type1 == TCL_NUMBER_WIDE) {
                w1 = *((const Tcl_WideInt*) ptr1);
#endif
            } else {
                w1 = 0;
            }
#if (LONG_MAX > 0x7fffffff) || !defined(TCL_WIDE_INT_IS_LONG)
            if (w1 != 0 && type2 == TCL_NUMBER_LONG && l2 <= 16
                    && w1 <= MaxBaseWide[l2-2] && w1 >= -MaxBaseWide[l2-2]) {
                /*
                 * Small powers of integers whose result is wide.
                 */

                Tcl_WideInt wResult = w1 * w1; /* b**2 */

                switch (l2) {
                case 2:
                    break;
                case 3:
                    wResult *= l1;      /* b**3 */
                    break;
                case 4:
                    wResult *= wResult; /* b**4 */
                    break;
                case 5:
                    wResult *= wResult; /* b**4 */
                    wResult *= w1;      /* b**5 */
                    break;
                case 6:
                    wResult *= w1;      /* b**3 */
                    wResult *= wResult; /* b**6 */
                    break;
                case 7:
                    wResult *= w1;      /* b**3 */
                    wResult *= wResult; /* b**6 */
                    wResult *= w1;      /* b**7 */
                    break;
                case 8:
                    wResult *= wResult; /* b**4 */
                    wResult *= wResult; /* b**8 */
                    break;
                case 9:
                    wResult *= wResult; /* b**4 */
                    wResult *= wResult; /* b**8 */
                    wResult *= w1;      /* b**9 */
                    break;
                case 10:
                    wResult *= wResult; /* b**4 */
                    wResult *= w1;      /* b**5 */
                    wResult *= wResult; /* b**10 */
                    break;
                case 11:
                    wResult *= wResult; /* b**4 */
                    wResult *= w1;      /* b**5 */
                    wResult *= wResult; /* b**10 */
                    wResult *= w1;      /* b**11 */
                    break;
                case 12:
                    wResult *= w1;      /* b**3 */
                    wResult *= wResult; /* b**6 */
                    wResult *= wResult; /* b**12 */
                    break;
                case 13:
                    wResult *= w1;      /* b**3 */
                    wResult *= wResult; /* b**6 */
                    wResult *= wResult; /* b**12 */
                    wResult *= w1;      /* b**13 */
                    break;
                case 14:
                    wResult *= w1;      /* b**3 */
                    wResult *= wResult; /* b**6 */
                    wResult *= w1;      /* b**7 */
                    wResult *= wResult; /* b**14 */
                    break;
                case 15:
                    wResult *= w1;      /* b**3 */
                    wResult *= wResult; /* b**6 */
                    wResult *= w1;      /* b**7 */
                    wResult *= wResult; /* b**14 */
                    wResult *= w1;      /* b**15 */
                    break;
                case 16:
                    wResult *= wResult; /* b**4 */
                    wResult *= wResult; /* b**8 */
                    wResult *= wResult; /* b**16 */
                    break;

                }
                TRACE(("%s %s => ", O2S(valuePtr), O2S(value2Ptr)));
                objResultPtr = Tcl_NewWideIntObj(wResult);
                TRACE(("%s\n", O2S(objResultPtr)));
                NEXT_INST_F(1, 2, 1);
            }

            /*
             * Handle cases of powers > 16 that still fit in a 64-bit word by
             * doing table lookup.
             */

            if (w1 >= 3 &&
                    (Tcl_WideUInt) w1 < (sizeof(Exp64Index)
                            / sizeof(unsigned short)) - 1) {
                unsigned short base =
                        Exp64Index[w1-3] + (unsigned short) l2 - 17;

                if (base < Exp64Index[w1-2]) {
                    /*
                     * 64-bit number raised to intermediate power, done by
                     * table lookup.
                     */

                    TRACE(("%s %s => ", O2S(valuePtr), O2S(value2Ptr)));
                    if (Tcl_IsShared(valuePtr)) {
                        objResultPtr = Tcl_NewWideIntObj(Exp64Value[base]);
                        TRACE(("%s\n", O2S(objResultPtr)));
                        NEXT_INST_F(1, 2, 1);
                    }
                    Tcl_SetWideIntObj(valuePtr, Exp64Value[base]);
                    TRACE(("%s\n", O2S(valuePtr)));
                    NEXT_INST_F(1, 1, 0);
                }
            }
            if (-w1 >= 3 &&
                    (Tcl_WideUInt) (-w1) < (sizeof(Exp64Index)
                            / sizeof(unsigned short)) - 1) {
                unsigned short base =
                        Exp64Index[-w1-3] + (unsigned short) l2 - 17;

                if (base < Exp64Index[-w1-2]) {
                    Tcl_WideInt wResult = (oddExponent) ?
                            -Exp64Value[base] : Exp64Value[base];
                    /*
                     * 64-bit number raised to intermediate power, done by
                     * table lookup.
                     */

                    TRACE(("%s %s => ", O2S(valuePtr), O2S(value2Ptr)));
                    if (Tcl_IsShared(valuePtr)) {
                        objResultPtr = Tcl_NewWideIntObj(wResult);
                        TRACE(("%s\n", O2S(objResultPtr)));
                        NEXT_INST_F(1, 2, 1);
                    }
                    Tcl_SetWideIntObj(valuePtr, wResult);
                    TRACE(("%s\n", O2S(valuePtr)));
                    NEXT_INST_F(1, 1, 0);
                }
            }
#endif

            goto overflow;
        }

        if ((*pc != INST_MULT)
                && (type1 != TCL_NUMBER_BIG) && (type2 != TCL_NUMBER_BIG)) {
            Tcl_WideInt w1, w2, wResult;

            TclGetWideIntFromObj(NULL, valuePtr, &w1);
            TclGetWideIntFromObj(NULL, value2Ptr, &w2);

            switch (*pc) {
            case INST_ADD:
                wResult = w1 + w2;
#ifndef NO_WIDE_TYPE
                if ((type1 == TCL_NUMBER_WIDE) || (type2 == TCL_NUMBER_WIDE))
#endif
                {
                    /*
                     * Check for overflow.
                     */

                    if (Overflowing(w1, w2, wResult)) {
                        goto overflow;
                    }
                }
                break;

            case INST_SUB:
                wResult = w1 - w2;
#ifndef NO_WIDE_TYPE
                if ((type1 == TCL_NUMBER_WIDE) || (type2 == TCL_NUMBER_WIDE))
#endif
                {
                    /*
                     * Must check for overflow. The macro tests for overflows
                     * in sums by looking at the sign bits. As we have a
                     * subtraction here, we are adding -w2. As -w2 could in
                     * turn overflow, we test with ~w2 instead: it has the
                     * opposite sign bit to w2 so it does the job. Note that
                     * the only "bad" case (w2==0) is irrelevant for this
                     * macro, as in that case w1 and wResult have the same
                     * sign and there is no overflow anyway.
                     */

                    if (Overflowing(w1, ~w2, wResult)) {
                        goto overflow;
                    }
                }
                break;

            case INST_DIV:
                if (w2 == 0) {
                    TRACE(("%s %s => DIVIDE BY ZERO\n",
                            O2S(valuePtr), O2S(value2Ptr)));
                    goto divideByZero;
                }

                /*
                 * Need a bignum to represent (LLONG_MIN / -1)
                 */

                if ((w1 == LLONG_MIN) && (w2 == -1)) {
                    goto overflow;
                }
                wResult = w1 / w2;

                /*
                 * Force Tcl's integer division rules.
                 * TODO: examine for logic simplification
                 */

                if (((wResult < 0) || ((wResult == 0) &&
                        ((w1 < 0 && w2 > 0) || (w1 > 0 && w2 < 0)))) &&
                        ((wResult * w2) != w1)) {
                    wResult -= 1;
                }
                break;
            default:
                /*
                 * Unused, here to silence compiler warning.
                 */

                wResult = 0;
            }

            TRACE(("%s %s => ", O2S(valuePtr), O2S(value2Ptr)));
            if (Tcl_IsShared(valuePtr)) {
                objResultPtr = Tcl_NewWideIntObj(wResult);
                TRACE(("%s\n", O2S(objResultPtr)));
                NEXT_INST_F(1, 2, 1);
            }
            Tcl_SetWideIntObj(valuePtr, wResult);
            TRACE(("%s\n", O2S(valuePtr)));
            NEXT_INST_F(1, 1, 0);
        }

    overflow:
        {
            mp_int big1, big2, bigResult, bigRemainder;

            TRACE(("%s %s => ", O2S(valuePtr), O2S(value2Ptr)));
            Tcl_TakeBignumFromObj(NULL, valuePtr, &big1);
            Tcl_TakeBignumFromObj(NULL, value2Ptr, &big2);
            mp_init(&bigResult);
            switch (*pc) {
            case INST_ADD:
                mp_add(&big1, &big2, &bigResult);
                break;
            case INST_SUB:
                mp_sub(&big1, &big2, &bigResult);
                break;
            case INST_MULT:
                mp_mul(&big1, &big2, &bigResult);
                break;
            case INST_DIV:
                if (mp_iszero(&big2)) {
                    TRACE(("%s %s => DIVIDE BY ZERO\n", O2S(valuePtr),
                            O2S(value2Ptr)));
                    mp_clear(&big1);
                    mp_clear(&big2);
                    mp_clear(&bigResult);
                    goto divideByZero;
                }
                mp_init(&bigRemainder);
                mp_div(&big1, &big2, &bigResult, &bigRemainder);
                /* TODO: internals intrusion */
                if (!mp_iszero(&bigRemainder)
                        && (bigRemainder.sign != big2.sign)) {
                    /*
                     * Convert to Tcl's integer division rules.
                     */

                    mp_sub_d(&bigResult, 1, &bigResult);
                    mp_add(&bigRemainder, &big2, &bigRemainder);
                }
                mp_clear(&bigRemainder);
                break;
            case INST_EXPON:
                if (big2.used > 1) {
                    Tcl_SetObjResult(interp,
                            Tcl_NewStringObj("exponent too large", -1));
                    mp_clear(&big1);
                    mp_clear(&big2);
                    mp_clear(&bigResult);
                    result = TCL_ERROR;
                    goto checkForCatch;
                }
                mp_expt_d(&big1, big2.dp[0], &bigResult);
                break;
            }
            mp_clear(&big1);
            mp_clear(&big2);
            if (Tcl_IsShared(valuePtr)) {
                objResultPtr = Tcl_NewBignumObj(&bigResult);
                TRACE(("%s\n", O2S(objResultPtr)));
                NEXT_INST_F(1, 2, 1);
            }
            Tcl_SetBignumObj(valuePtr, &bigResult);
            TRACE(("%s\n", O2S(valuePtr)));
            NEXT_INST_F(1, 1, 0);
        }
    }

    case INST_LNOT: {
        int b;
        Tcl_Obj *valuePtr = OBJ_AT_TOS;

        /* TODO - check claim that taking address of b harms performance */
        /* TODO - consider optimization search for constants */
        result = TclGetBooleanFromObj(NULL, valuePtr, &b);
        if (result != TCL_OK) {
            TRACE(("\"%.20s\" => ILLEGAL TYPE %s\n", O2S(valuePtr),
                    (valuePtr->typePtr? valuePtr->typePtr->name : "null")));
            IllegalExprOperandType(interp, pc, valuePtr);
            goto checkForCatch;
        }
        /* TODO: Consider peephole opt. */
        objResultPtr = constants[!b];
        NEXT_INST_F(1, 1, 1);
    }

    case INST_BITNOT: {
        mp_int big;
        ClientData ptr;
        int type;
        Tcl_Obj *valuePtr = OBJ_AT_TOS;

        result = GetNumberFromObj(NULL, valuePtr, &ptr, &type);
        if ((result != TCL_OK)
                || (type == TCL_NUMBER_NAN) || (type == TCL_NUMBER_DOUBLE)) {
            /*
             * ... ~$NonInteger => raise an error.
             */

            result = TCL_ERROR;
            TRACE(("\"%.20s\" => ILLEGAL TYPE %s \n", O2S(valuePtr),
                    (valuePtr->typePtr? valuePtr->typePtr->name : "null")));
            IllegalExprOperandType(interp, pc, valuePtr);
            goto checkForCatch;
        }
        if (type == TCL_NUMBER_LONG) {
            long l = *((const long *)ptr);

            if (Tcl_IsShared(valuePtr)) {
                TclNewLongObj(objResultPtr, ~l);
                NEXT_INST_F(1, 1, 1);
            }
            TclSetLongObj(valuePtr, ~l);
            NEXT_INST_F(1, 0, 0);
        }
#ifndef NO_WIDE_TYPE
        if (type == TCL_NUMBER_WIDE) {
            Tcl_WideInt w = *((const Tcl_WideInt *)ptr);

            if (Tcl_IsShared(valuePtr)) {
                objResultPtr = Tcl_NewWideIntObj(~w);
                NEXT_INST_F(1, 1, 1);
            }
            Tcl_SetWideIntObj(valuePtr, ~w);
            NEXT_INST_F(1, 0, 0);
        }
#endif
        Tcl_TakeBignumFromObj(NULL, valuePtr, &big);
        /* ~a = - a - 1 */
        mp_neg(&big, &big);
        mp_sub_d(&big, 1, &big);
        if (Tcl_IsShared(valuePtr)) {
            objResultPtr = Tcl_NewBignumObj(&big);
            NEXT_INST_F(1, 1, 1);
        }
        Tcl_SetBignumObj(valuePtr, &big);
        NEXT_INST_F(1, 0, 0);
    }

    case INST_UMINUS: {
        ClientData ptr;
        int type;
        Tcl_Obj *valuePtr = OBJ_AT_TOS;

        result = GetNumberFromObj(NULL, valuePtr, &ptr, &type);
        if ((result != TCL_OK)
#ifndef ACCEPT_NAN
                || (type == TCL_NUMBER_NAN)
#endif
                ) {
            result = TCL_ERROR;
            TRACE(("\"%.20s\" => ILLEGAL TYPE %s \n", O2S(valuePtr),
                    (valuePtr->typePtr? valuePtr->typePtr->name : "null")));
            IllegalExprOperandType(interp, pc, valuePtr);
            goto checkForCatch;
        }
        switch (type) {
        case TCL_NUMBER_DOUBLE: {
            double d;

            if (Tcl_IsShared(valuePtr)) {
                TclNewDoubleObj(objResultPtr, -(*((const double *)ptr)));
                NEXT_INST_F(1, 1, 1);
            }
            d = *((const double *)ptr);
            TclSetDoubleObj(valuePtr, -d);
            NEXT_INST_F(1, 0, 0);
        }
        case TCL_NUMBER_LONG: {
            long l = *((const long *)ptr);

            if (l != LONG_MIN) {
                if (Tcl_IsShared(valuePtr)) {
                    TclNewLongObj(objResultPtr, -l);
                    NEXT_INST_F(1, 1, 1);
                }
                TclSetLongObj(valuePtr, -l);
                NEXT_INST_F(1, 0, 0);
            }
            /* FALLTHROUGH */
        }
#ifndef NO_WIDE_TYPE
        case TCL_NUMBER_WIDE: {
            Tcl_WideInt w;

            if (type == TCL_NUMBER_LONG) {
                w = (Tcl_WideInt)(*((const long *)ptr));
            } else {
                w = *((const Tcl_WideInt *)ptr);
            }
            if (w != LLONG_MIN) {
                if (Tcl_IsShared(valuePtr)) {
                    objResultPtr = Tcl_NewWideIntObj(-w);
                    NEXT_INST_F(1, 1, 1);
                }
                Tcl_SetWideIntObj(valuePtr, -w);
                NEXT_INST_F(1, 0, 0);
            }
            /* FALLTHROUGH */
        }
#endif
        case TCL_NUMBER_BIG: {
            mp_int big;

            switch (type) {
#ifdef NO_WIDE_TYPE
            case TCL_NUMBER_LONG:
                TclBNInitBignumFromLong(&big, *(const long *) ptr);
                break;
#else
            case TCL_NUMBER_WIDE:
                TclBNInitBignumFromWideInt(&big, *(const Tcl_WideInt *) ptr);
                break;
#endif
            case TCL_NUMBER_BIG:
                Tcl_TakeBignumFromObj(NULL, valuePtr, &big);
            }
            mp_neg(&big, &big);
            if (Tcl_IsShared(valuePtr)) {
                objResultPtr = Tcl_NewBignumObj(&big);
                NEXT_INST_F(1, 1, 1);
            }
            Tcl_SetBignumObj(valuePtr, &big);
            NEXT_INST_F(1, 0, 0);
        }
        case TCL_NUMBER_NAN:
            /* -NaN => NaN */
            NEXT_INST_F(1, 0, 0);
        }
    }

    case INST_UPLUS:
    case INST_TRY_CVT_TO_NUMERIC: {
        /*
         * Try to convert the topmost stack object to numeric object. This is
         * done in order to support [expr]'s policy of interpreting operands
         * if at all possible as numbers first, then strings.
         */

        ClientData ptr;
        int type;
        Tcl_Obj *valuePtr = OBJ_AT_TOS;

        if (GetNumberFromObj(NULL, valuePtr, &ptr, &type) != TCL_OK) {
            if (*pc == INST_UPLUS) {
                /*
                 * ... +$NonNumeric => raise an error.
                 */

                result = TCL_ERROR;
                TRACE(("\"%.20s\" => ILLEGAL TYPE %s \n", O2S(valuePtr),
                        (valuePtr->typePtr? valuePtr->typePtr->name:"null")));
                IllegalExprOperandType(interp, pc, valuePtr);
                goto checkForCatch;
            } else {
                /* ... TryConvertToNumeric($NonNumeric) is acceptable */
                TRACE(("\"%.20s\" => not numeric\n", O2S(valuePtr)));
                NEXT_INST_F(1, 0, 0);
            }
        }
#ifndef ACCEPT_NAN
        if (type == TCL_NUMBER_NAN) {
            result = TCL_ERROR;
            if (*pc == INST_UPLUS) {
                /*
                 * ... +$NonNumeric => raise an error.
                 */

                TRACE(("\"%.20s\" => ILLEGAL TYPE %s \n", O2S(valuePtr),
                        (valuePtr->typePtr? valuePtr->typePtr->name:"null")));
                IllegalExprOperandType(interp, pc, valuePtr);
            } else {
                /*
                 * Numeric conversion of NaN -> error.
                 */

                TRACE(("\"%.20s\" => IEEE FLOATING PT ERROR\n",
                        O2S(objResultPtr)));
                TclExprFloatError(interp, *((const double *)ptr));
            }
            goto checkForCatch;
        }
#endif

        /*
         * Ensure that the numeric value has a string rep the same as the
         * formatted version of its internal rep. This is used, e.g., to make
         * sure that "expr {0001}" yields "1", not "0001". We implement this
         * by _discarding_ the string rep since we know it will be
         * regenerated, if needed later, by formatting the internal rep's
         * value.
         */

        if (valuePtr->bytes == NULL) {
            TRACE(("\"%.20s\" => numeric, same Tcl_Obj\n", O2S(valuePtr)));
            NEXT_INST_F(1, 0, 0);
        }
        if (Tcl_IsShared(valuePtr)) {
            /*
             * Here we do some surgery within the Tcl_Obj internals. We want
             * to copy the intrep, but not the string, so we temporarily hide
             * the string so we do not copy it.
             */

            char *savedString = valuePtr->bytes;

            valuePtr->bytes = NULL;
            objResultPtr = Tcl_DuplicateObj(valuePtr);
            valuePtr->bytes = savedString;
            TRACE(("\"%.20s\" => numeric, new Tcl_Obj\n", O2S(valuePtr)));
            NEXT_INST_F(1, 1, 1);
        }
        TclInvalidateStringRep(valuePtr);
        TRACE(("\"%.20s\" => numeric, same Tcl_Obj\n", O2S(valuePtr)));
        NEXT_INST_F(1, 0, 0);
    }

    case INST_BREAK:
        /*
        DECACHE_STACK_INFO();
        Tcl_ResetResult(interp);
        CACHE_STACK_INFO();
        */
        result = TCL_BREAK;
        cleanup = 0;
        goto processExceptionReturn;

    case INST_CONTINUE:
        /*
        DECACHE_STACK_INFO();
        Tcl_ResetResult(interp);
        CACHE_STACK_INFO();
        */
        result = TCL_CONTINUE;
        cleanup = 0;
        goto processExceptionReturn;

    case INST_FOREACH_START4: {
        /*
         * Initialize the temporary local var that holds the count of the
         * number of iterations of the loop body to -1.
         */

        int opnd, iterTmpIndex;
        ForeachInfo *infoPtr;
        Var *iterVarPtr;
        Tcl_Obj *oldValuePtr;

        opnd = TclGetUInt4AtPtr(pc+1);
        infoPtr = (ForeachInfo *) codePtr->auxDataArrayPtr[opnd].clientData;
        iterTmpIndex = infoPtr->loopCtTemp;
        iterVarPtr = &(compiledLocals[iterTmpIndex]);
        oldValuePtr = iterVarPtr->value.objPtr;

        if (oldValuePtr == NULL) {
            TclNewLongObj(iterVarPtr->value.objPtr, -1);
            Tcl_IncrRefCount(iterVarPtr->value.objPtr);
        } else {
            TclSetLongObj(oldValuePtr, -1);
        }
        TRACE(("%u => loop iter count temp %d\n", opnd, iterTmpIndex));

#ifndef TCL_COMPILE_DEBUG
        /*
         * Remark that the compiler ALWAYS sets INST_FOREACH_STEP4 immediately
         * after INST_FOREACH_START4 - let us just fall through instead of
         * jumping back to the top.
         */

        pc += 5;
        TCL_DTRACE_INST_NEXT();
#else
        NEXT_INST_F(5, 0, 0);
#endif
    }

    case INST_FOREACH_STEP4: {
        /*
         * "Step" a foreach loop (i.e., begin its next iteration) by assigning
         * the next value list element to each loop var.
         */

        ForeachInfo *infoPtr;
        ForeachVarList *varListPtr;
        Tcl_Obj *listPtr,*valuePtr, *value2Ptr, **elements;
        Var *iterVarPtr, *listVarPtr, *varPtr;
        int opnd, numLists, iterNum, listTmpIndex, listLen, numVars;
        int varIndex, valIndex, continueLoop, j;
        long i;

        opnd = TclGetUInt4AtPtr(pc+1);
        infoPtr = (ForeachInfo *) codePtr->auxDataArrayPtr[opnd].clientData;
        numLists = infoPtr->numLists;

        /*
         * Increment the temp holding the loop iteration number.
         */

        iterVarPtr = &(compiledLocals[infoPtr->loopCtTemp]);
        valuePtr = iterVarPtr->value.objPtr;
        iterNum = (valuePtr->internalRep.longValue + 1);
        TclSetLongObj(valuePtr, iterNum);

        /*
         * Check whether all value lists are exhausted and we should stop the
         * loop.
         */

        continueLoop = 0;
        listTmpIndex = infoPtr->firstValueTemp;
        for (i = 0;  i < numLists;  i++) {
            varListPtr = infoPtr->varLists[i];
            numVars = varListPtr->numVars;

            listVarPtr = &(compiledLocals[listTmpIndex]);
            listPtr = listVarPtr->value.objPtr;
            result = TclListObjLength(interp, listPtr, &listLen);
            if (result == TCL_OK) {
                if (listLen > (iterNum * numVars)) {
                    continueLoop = 1;
                }
                listTmpIndex++;
            } else {
                TRACE_WITH_OBJ(("%u => ERROR converting list %ld, \"%s\": ",
                        opnd, i, O2S(listPtr)), Tcl_GetObjResult(interp));
                goto checkForCatch;
            }
        }

        /*
         * If some var in some var list still has a remaining list element
         * iterate one more time. Assign to var the next element from its
         * value list. We already checked above that each list temp holds a
         * valid list object (by calling Tcl_ListObjLength), but cannot rely
         * on that check remaining valid: one list could have been shimmered
         * as a side effect of setting a traced variable.
         */

        if (continueLoop) {
            listTmpIndex = infoPtr->firstValueTemp;
            for (i = 0;  i < numLists;  i++) {
                varListPtr = infoPtr->varLists[i];
                numVars = varListPtr->numVars;

                listVarPtr = &(compiledLocals[listTmpIndex]);
                listPtr = TclListObjCopy(NULL, listVarPtr->value.objPtr);
                TclListObjGetElements(interp, listPtr, &listLen, &elements);

                valIndex = (iterNum * numVars);
                for (j = 0;  j < numVars;  j++) {
                    if (valIndex >= listLen) {
                        TclNewObj(valuePtr);
                    } else {
                        valuePtr = elements[valIndex];
                    }

                    varIndex = varListPtr->varIndexes[j];
                    varPtr = &(compiledLocals[varIndex]);
                    while (TclIsVarLink(varPtr)) {
                        varPtr = varPtr->value.linkPtr;
                    }
                    if (TclIsVarDirectWritable(varPtr)) {
                        value2Ptr = varPtr->value.objPtr;
                        if (valuePtr != value2Ptr) {
                            if (value2Ptr != NULL) {
                                TclDecrRefCount(value2Ptr);
                            }
                            varPtr->value.objPtr = valuePtr;
                            Tcl_IncrRefCount(valuePtr);
                        }
                    } else {
                        DECACHE_STACK_INFO();
                        value2Ptr = TclPtrSetVar(interp, varPtr, NULL, NULL,
                                NULL, valuePtr, TCL_LEAVE_ERR_MSG, varIndex);
                        CACHE_STACK_INFO();
                        if (value2Ptr == NULL) {
                            TRACE_WITH_OBJ((
                                    "%u => ERROR init. index temp %d: ",
                                    opnd,varIndex), Tcl_GetObjResult(interp));
                            result = TCL_ERROR;
                            TclDecrRefCount(listPtr);
                            goto checkForCatch;
                        }
                    }
                    valIndex++;
                }
                TclDecrRefCount(listPtr);
                listTmpIndex++;
            }
        }
        TRACE(("%u => %d lists, iter %d, %s loop\n", opnd, numLists,
                iterNum, (continueLoop? "continue" : "exit")));

        /*
         * Run-time peep-hole optimisation: the compiler ALWAYS follows
         * INST_FOREACH_STEP4 with an INST_JUMP_FALSE. We just skip that
         * instruction and jump direct from here.
         */

        pc += 5;
        if (*pc == INST_JUMP_FALSE1) {
            NEXT_INST_F((continueLoop? 2 : TclGetInt1AtPtr(pc+1)), 0, 0);
        } else {
            NEXT_INST_F((continueLoop? 5 : TclGetInt4AtPtr(pc+1)), 0, 0);
        }
    }

    case INST_BEGIN_CATCH4:
        /*
         * Record start of the catch command with exception range index equal
         * to the operand. Push the current stack depth onto the special catch
         * stack.
         */

        *(++catchTop) = CURR_DEPTH;
        TRACE(("%u => catchTop=%d, stackTop=%d\n",
                TclGetUInt4AtPtr(pc+1), (catchTop - initCatchTop - 1),
                (int) CURR_DEPTH));
        NEXT_INST_F(5, 0, 0);

    case INST_END_CATCH:
        catchTop--;
        Tcl_ResetResult(interp);
        result = TCL_OK;
        TRACE(("=> catchTop=%d\n", (catchTop - initCatchTop - 1)));
        NEXT_INST_F(1, 0, 0);

    case INST_PUSH_RESULT:
        objResultPtr = Tcl_GetObjResult(interp);
        TRACE_WITH_OBJ(("=> "), objResultPtr);

        /*
         * See the comments at INST_INVOKE_STK
         */
        {
            Tcl_Obj *newObjResultPtr;

            TclNewObj(newObjResultPtr);
            Tcl_IncrRefCount(newObjResultPtr);
            iPtr->objResultPtr = newObjResultPtr;
        }

        NEXT_INST_F(1, 0, -1);

    case INST_PUSH_RETURN_CODE:
        TclNewIntObj(objResultPtr, result);
        TRACE(("=> %u\n", result));
        NEXT_INST_F(1, 0, 1);

    case INST_PUSH_RETURN_OPTIONS:
        objResultPtr = Tcl_GetReturnOptions(interp, result);
        TRACE_WITH_OBJ(("=> "), objResultPtr);
        NEXT_INST_F(1, 0, 1);

/* TODO: normalize "valPtr" to "valuePtr" */
    {
        int opnd, opnd2, allocateDict;
        Tcl_Obj *dictPtr, *valPtr;
        Var *varPtr;

    case INST_DICT_GET:
        opnd = TclGetUInt4AtPtr(pc+1);
        TRACE(("%u => ", opnd));
        dictPtr = OBJ_AT_DEPTH(opnd);
        if (opnd > 1) {
            dictPtr = TclTraceDictPath(interp, dictPtr, opnd-1,
                    &OBJ_AT_DEPTH(opnd-1), DICT_PATH_READ);
            if (dictPtr == NULL) {
                TRACE_WITH_OBJ((
                        "%u => ERROR tracing dictionary path into \"%s\": ",
                        opnd, O2S(OBJ_AT_DEPTH(opnd))),
                        Tcl_GetObjResult(interp));
                result = TCL_ERROR;
                goto checkForCatch;
            }
        }
        result = Tcl_DictObjGet(interp, dictPtr, OBJ_AT_TOS, &objResultPtr);
        if ((result == TCL_OK) && objResultPtr) {
            TRACE_APPEND(("%.30s\n", O2S(objResultPtr)));
            NEXT_INST_V(5, opnd+1, 1);
        }
        if (result != TCL_OK) {
            TRACE_WITH_OBJ((
                    "%u => ERROR reading leaf dictionary key \"%s\": ",
                    opnd, O2S(dictPtr)), Tcl_GetObjResult(interp));
        } else {
            /*Tcl_ResetResult(interp);*/
            Tcl_AppendResult(interp, "key \"", TclGetString(OBJ_AT_TOS),
                    "\" not known in dictionary", NULL);
            TRACE_WITH_OBJ(("%u => ERROR ", opnd), Tcl_GetObjResult(interp));
            result = TCL_ERROR;
        }
        goto checkForCatch;

    case INST_DICT_SET:
    case INST_DICT_UNSET:
    case INST_DICT_INCR_IMM:
        opnd = TclGetUInt4AtPtr(pc+1);
        opnd2 = TclGetUInt4AtPtr(pc+5);

        varPtr = &(compiledLocals[opnd2]);
        while (TclIsVarLink(varPtr)) {
            varPtr = varPtr->value.linkPtr;
        }
        TRACE(("%u %u => ", opnd, opnd2));
        if (TclIsVarDirectReadable(varPtr)) {
            dictPtr = varPtr->value.objPtr;
        } else {
            DECACHE_STACK_INFO();
            dictPtr = TclPtrGetVar(interp, varPtr, NULL,NULL,NULL, 0, opnd2);
            CACHE_STACK_INFO();
        }
        if (dictPtr == NULL) {
            TclNewObj(dictPtr);
            allocateDict = 1;
        } else {
            allocateDict = Tcl_IsShared(dictPtr);
            if (allocateDict) {
                dictPtr = Tcl_DuplicateObj(dictPtr);
            }
        }

        switch (*pc) {
        case INST_DICT_SET:
            cleanup = opnd + 1;
            result = Tcl_DictObjPutKeyList(interp, dictPtr, opnd,
                    &OBJ_AT_DEPTH(opnd), OBJ_AT_TOS);
            break;
        case INST_DICT_INCR_IMM:
            cleanup = 1;
            opnd = TclGetInt4AtPtr(pc+1);
            result = Tcl_DictObjGet(interp, dictPtr, OBJ_AT_TOS, &valPtr);
            if (result != TCL_OK) {
                break;
            }
            if (valPtr == NULL) {
                Tcl_DictObjPut(NULL, dictPtr, OBJ_AT_TOS,Tcl_NewIntObj(opnd));
            } else {
                Tcl_Obj *incrPtr = Tcl_NewIntObj(opnd);

                Tcl_IncrRefCount(incrPtr);
                if (Tcl_IsShared(valPtr)) {
                    valPtr = Tcl_DuplicateObj(valPtr);
                    Tcl_DictObjPut(NULL, dictPtr, OBJ_AT_TOS, valPtr);
                }
                result = TclIncrObj(interp, valPtr, incrPtr);
                if (result == TCL_OK) {
                    Tcl_InvalidateStringRep(dictPtr);
                }
                TclDecrRefCount(incrPtr);
            }
            break;
        case INST_DICT_UNSET:
            cleanup = opnd;
            result = Tcl_DictObjRemoveKeyList(interp, dictPtr, opnd,
                    &OBJ_AT_DEPTH(opnd-1));
            break;
        default:
            cleanup = 0; /* stop compiler warning */
            Tcl_Panic("Should not happen!");
        }

        if (result != TCL_OK) {
            if (allocateDict) {
                TclDecrRefCount(dictPtr);
            }
            TRACE_WITH_OBJ(("%u %u => ERROR updating dictionary: ",
                    opnd, opnd2), Tcl_GetObjResult(interp));
            goto checkForCatch;
        }

        if (TclIsVarDirectWritable(varPtr)) {
            if (allocateDict) {
                Tcl_Obj *oldValuePtr = varPtr->value.objPtr;

                Tcl_IncrRefCount(dictPtr);
                if (oldValuePtr != NULL) {
                    TclDecrRefCount(oldValuePtr);
                }
                varPtr->value.objPtr = dictPtr;
            }
            objResultPtr = dictPtr;
        } else {
            Tcl_IncrRefCount(dictPtr);
            DECACHE_STACK_INFO();
            objResultPtr = TclPtrSetVar(interp, varPtr, NULL, NULL, NULL,
                    dictPtr, TCL_LEAVE_ERR_MSG, opnd2);
            CACHE_STACK_INFO();
            TclDecrRefCount(dictPtr);
            if (objResultPtr == NULL) {
                TRACE_APPEND(("ERROR: %.30s\n",
                        O2S(Tcl_GetObjResult(interp))));
                result = TCL_ERROR;
                goto checkForCatch;
            }
        }
#ifndef TCL_COMPILE_DEBUG
        if (*(pc+9) == INST_POP) {
            NEXT_INST_V(10, cleanup, 0);
        }
#endif
        TRACE_APPEND(("%.30s\n", O2S(objResultPtr)));
        NEXT_INST_V(9, cleanup, 1);

    case INST_DICT_APPEND:
    case INST_DICT_LAPPEND:
        opnd = TclGetUInt4AtPtr(pc+1);

        varPtr = &(compiledLocals[opnd]);
        while (TclIsVarLink(varPtr)) {
            varPtr = varPtr->value.linkPtr;
        }
        TRACE(("%u => ", opnd));
        if (TclIsVarDirectReadable(varPtr)) {
            dictPtr = varPtr->value.objPtr;
        } else {
            DECACHE_STACK_INFO();
            dictPtr = TclPtrGetVar(interp, varPtr, NULL, NULL, NULL, 0, opnd);
            CACHE_STACK_INFO();
        }
        if (dictPtr == NULL) {
            TclNewObj(dictPtr);
            allocateDict = 1;
        } else {
            allocateDict = Tcl_IsShared(dictPtr);
            if (allocateDict) {
                dictPtr = Tcl_DuplicateObj(dictPtr);
            }
        }

        result = Tcl_DictObjGet(interp, dictPtr, OBJ_UNDER_TOS, &valPtr);
        if (result != TCL_OK) {
            if (allocateDict) {
                TclDecrRefCount(dictPtr);
            }
            goto checkForCatch;
        }

        /*
         * Note that a non-existent key results in a NULL valPtr, which is a
         * case handled separately below. What we *can* say at this point is
         * that the write-back will always succeed.
         */

        switch (*pc) {
        case INST_DICT_APPEND:
            if (valPtr == NULL) {
                valPtr = OBJ_AT_TOS;
            } else {
                if (Tcl_IsShared(valPtr)) {
                    valPtr = Tcl_DuplicateObj(valPtr);
                }
                Tcl_AppendObjToObj(valPtr, OBJ_AT_TOS);
            }
            break;
        case INST_DICT_LAPPEND:
            /*
             * More complex because list-append can fail.
             */

            if (valPtr == NULL) {
                valPtr = Tcl_NewListObj(1, &OBJ_AT_TOS);
            } else if (Tcl_IsShared(valPtr)) {
                valPtr = Tcl_DuplicateObj(valPtr);
                result = Tcl_ListObjAppendElement(interp, valPtr, OBJ_AT_TOS);
                if (result != TCL_OK) {
                    TclDecrRefCount(valPtr);
                    if (allocateDict) {
                        TclDecrRefCount(dictPtr);
                    }
                    goto checkForCatch;
                }
            } else {
                result = Tcl_ListObjAppendElement(interp, valPtr, OBJ_AT_TOS);
                if (result != TCL_OK) {
                    if (allocateDict) {
                        TclDecrRefCount(dictPtr);
                    }
                    goto checkForCatch;
                }
            }
            break;
        default:
            Tcl_Panic("Should not happen!");
        }

        Tcl_DictObjPut(NULL, dictPtr, OBJ_UNDER_TOS, valPtr);

        if (TclIsVarDirectWritable(varPtr)) {
            if (allocateDict) {
                Tcl_Obj *oldValuePtr = varPtr->value.objPtr;

                Tcl_IncrRefCount(dictPtr);
                if (oldValuePtr != NULL) {
                    TclDecrRefCount(oldValuePtr);
                }
                varPtr->value.objPtr = dictPtr;
            }
            objResultPtr = dictPtr;
        } else {
            Tcl_IncrRefCount(dictPtr);
            DECACHE_STACK_INFO();
            objResultPtr = TclPtrSetVar(interp, varPtr, NULL, NULL, NULL,
                    dictPtr, TCL_LEAVE_ERR_MSG, opnd);
            CACHE_STACK_INFO();
            TclDecrRefCount(dictPtr);
            if (objResultPtr == NULL) {
                TRACE_APPEND(("ERROR: %.30s\n",
                        O2S(Tcl_GetObjResult(interp))));
                result = TCL_ERROR;
                goto checkForCatch;
            }
        }
#ifndef TCL_COMPILE_DEBUG
        if (*(pc+5) == INST_POP) {
            NEXT_INST_F(6, 2, 0);
        }
#endif
        TRACE_APPEND(("%.30s\n", O2S(objResultPtr)));
        NEXT_INST_F(5, 2, 1);
    }

    {
        int opnd, done;
        Tcl_Obj *statePtr, *dictPtr, *keyPtr, *valuePtr, *emptyPtr;
        Var *varPtr;
        Tcl_DictSearch *searchPtr;

    case INST_DICT_FIRST:
        opnd = TclGetUInt4AtPtr(pc+1);
        TRACE(("%u => ", opnd));
        dictPtr = POP_OBJECT();
        searchPtr = (Tcl_DictSearch *) ckalloc(sizeof(Tcl_DictSearch));
        result = Tcl_DictObjFirst(interp, dictPtr, searchPtr, &keyPtr,
                &valuePtr, &done);
        if (result != TCL_OK) {
            ckfree((char *) searchPtr);
            goto checkForCatch;
        }
        TclNewObj(statePtr);
        statePtr->typePtr = &dictIteratorType;
        statePtr->internalRep.twoPtrValue.ptr1 = (void *) searchPtr;
        statePtr->internalRep.twoPtrValue.ptr2 = (void *) dictPtr;
        varPtr = (compiledLocals + opnd);
        if (varPtr->value.objPtr) {
            if (varPtr->value.objPtr->typePtr != &dictIteratorType) {
                TclDecrRefCount(varPtr->value.objPtr);
            } else {
                Tcl_Panic("mis-issued dictFirst!");
            }
        }
        varPtr->value.objPtr = statePtr;
        Tcl_IncrRefCount(statePtr);
        goto pushDictIteratorResult;

    case INST_DICT_NEXT:
        opnd = TclGetUInt4AtPtr(pc+1);
        TRACE(("%u => ", opnd));
        statePtr = compiledLocals[opnd].value.objPtr;
        if (statePtr == NULL || statePtr->typePtr != &dictIteratorType) {
            Tcl_Panic("mis-issued dictNext!");
        }
        searchPtr = (Tcl_DictSearch *) statePtr->internalRep.twoPtrValue.ptr1;
        Tcl_DictObjNext(searchPtr, &keyPtr, &valuePtr, &done);
    pushDictIteratorResult:
        if (done) {
            TclNewObj(emptyPtr);
            PUSH_OBJECT(emptyPtr);
            PUSH_OBJECT(emptyPtr);
        } else {
            PUSH_OBJECT(valuePtr);
            PUSH_OBJECT(keyPtr);
        }
        TRACE_APPEND(("\"%.30s\" \"%.30s\" %d",
                O2S(OBJ_UNDER_TOS), O2S(OBJ_AT_TOS), done));
        objResultPtr = constants[done];
        /* TODO: consider opt like INST_FOREACH_STEP4 */
        NEXT_INST_F(5, 0, 1);

    case INST_DICT_DONE:
        opnd = TclGetUInt4AtPtr(pc+1);
        TRACE(("%u => ", opnd));
        statePtr = compiledLocals[opnd].value.objPtr;
        if (statePtr == NULL) {
            Tcl_Panic("mis-issued dictDone!");
        }

        if (statePtr->typePtr == &dictIteratorType) {
            /*
             * First kill the search, and then release the reference to the
             * dictionary that we were holding.
             */

            searchPtr = (Tcl_DictSearch *)
                    statePtr->internalRep.twoPtrValue.ptr1;
            Tcl_DictObjDone(searchPtr);
            ckfree((char *) searchPtr);

            dictPtr = (Tcl_Obj *) statePtr->internalRep.twoPtrValue.ptr2;
            TclDecrRefCount(dictPtr);

            /*
             * Set the internal variable to an empty object to signify that we
             * don't hold an iterator.
             */

            TclDecrRefCount(statePtr);
            TclNewObj(emptyPtr);
            compiledLocals[opnd].value.objPtr = emptyPtr;
            Tcl_IncrRefCount(emptyPtr);
        }
        NEXT_INST_F(5, 0, 0);
    }

    {
        int opnd, opnd2, i, length, allocdict;
        Tcl_Obj **keyPtrPtr, *dictPtr;
        DictUpdateInfo *duiPtr;
        Var *varPtr;

    case INST_DICT_UPDATE_START:
        opnd = TclGetUInt4AtPtr(pc+1);
        opnd2 = TclGetUInt4AtPtr(pc+5);
        varPtr = &(compiledLocals[opnd]);
        duiPtr = codePtr->auxDataArrayPtr[opnd2].clientData;
        while (TclIsVarLink(varPtr)) {
            varPtr = varPtr->value.linkPtr;
        }
        TRACE(("%u => ", opnd));
        if (TclIsVarDirectReadable(varPtr)) {
            dictPtr = varPtr->value.objPtr;
        } else {
            DECACHE_STACK_INFO();
            dictPtr = TclPtrGetVar(interp, varPtr, NULL, NULL, NULL,
                    TCL_LEAVE_ERR_MSG, opnd);
            CACHE_STACK_INFO();
            if (dictPtr == NULL) {
                goto dictUpdateStartFailed;
            }
        }
        if (TclListObjGetElements(interp, OBJ_AT_TOS, &length,
                &keyPtrPtr) != TCL_OK) {
            goto dictUpdateStartFailed;
        }
        if (length != duiPtr->length) {
            Tcl_Panic("dictUpdateStart argument length mismatch");
        }
        for (i=0 ; i<length ; i++) {
            Tcl_Obj *valPtr;

            if (Tcl_DictObjGet(interp, dictPtr, keyPtrPtr[i],
                    &valPtr) != TCL_OK) {
                goto dictUpdateStartFailed;
            }
            varPtr = &(compiledLocals[duiPtr->varIndices[i]]);
            while (TclIsVarLink(varPtr)) {
                varPtr = varPtr->value.linkPtr;
            }
            DECACHE_STACK_INFO();
            if (valPtr == NULL) {
                TclObjUnsetVar2(interp,
                        localName(iPtr->varFramePtr, duiPtr->varIndices[i]),
                        NULL, 0);
            } else if (TclPtrSetVar(interp, varPtr, NULL, NULL, NULL,
                    valPtr, TCL_LEAVE_ERR_MSG,
                    duiPtr->varIndices[i]) == NULL) {
                CACHE_STACK_INFO();
            dictUpdateStartFailed:
                result = TCL_ERROR;
                goto checkForCatch;
            }
            CACHE_STACK_INFO();
        }
        NEXT_INST_F(9, 0, 0);

    case INST_DICT_UPDATE_END:
        opnd = TclGetUInt4AtPtr(pc+1);
        opnd2 = TclGetUInt4AtPtr(pc+5);
        varPtr = &(compiledLocals[opnd]);
        duiPtr = codePtr->auxDataArrayPtr[opnd2].clientData;
        while (TclIsVarLink(varPtr)) {
            varPtr = varPtr->value.linkPtr;
        }
        TRACE(("%u => ", opnd));
        if (TclIsVarDirectReadable(varPtr)) {
            dictPtr = varPtr->value.objPtr;
        } else {
            DECACHE_STACK_INFO();
            dictPtr = TclPtrGetVar(interp, varPtr, NULL, NULL, NULL, 0, opnd);
            CACHE_STACK_INFO();
        }
        if (dictPtr == NULL) {
            NEXT_INST_F(9, 1, 0);
        }
        if (Tcl_DictObjSize(interp, dictPtr, &length) != TCL_OK
                || TclListObjGetElements(interp, OBJ_AT_TOS, &length,
                        &keyPtrPtr) != TCL_OK) {
            result = TCL_ERROR;
            goto checkForCatch;
        }
        allocdict = Tcl_IsShared(dictPtr);
        if (allocdict) {
            dictPtr = Tcl_DuplicateObj(dictPtr);
        }
        for (i=0 ; i<length ; i++) {
            Tcl_Obj *valPtr;
            Var *var2Ptr;

            var2Ptr = &(compiledLocals[duiPtr->varIndices[i]]);
            while (TclIsVarLink(var2Ptr)) {
                var2Ptr = var2Ptr->value.linkPtr;
            }
            if (TclIsVarDirectReadable(var2Ptr)) {
                valPtr = var2Ptr->value.objPtr;
            } else {
                DECACHE_STACK_INFO();
                valPtr = TclPtrGetVar(interp, var2Ptr, NULL, NULL, NULL, 0,
                        duiPtr->varIndices[i]);
                CACHE_STACK_INFO();
            }
            if (valPtr == NULL) {
                Tcl_DictObjRemove(interp, dictPtr, keyPtrPtr[i]);
            } else if (dictPtr == valPtr) {
                Tcl_DictObjPut(interp, dictPtr, keyPtrPtr[i],
                        Tcl_DuplicateObj(valPtr));
            } else {
                Tcl_DictObjPut(interp, dictPtr, keyPtrPtr[i], valPtr);
            }
        }
        if (TclIsVarDirectWritable(varPtr)) {
            Tcl_IncrRefCount(dictPtr);
            TclDecrRefCount(varPtr->value.objPtr);
            varPtr->value.objPtr = dictPtr;
        } else {
            DECACHE_STACK_INFO();
            objResultPtr = TclPtrSetVar(interp, varPtr, NULL, NULL, NULL,
                    dictPtr, TCL_LEAVE_ERR_MSG, opnd);
            CACHE_STACK_INFO();
            if (objResultPtr == NULL) {
                if (allocdict) {
                    TclDecrRefCount(dictPtr);
                }
                result = TCL_ERROR;
                goto checkForCatch;
            }
        }
        NEXT_INST_F(9, 1, 0);
    }

    default:
        Tcl_Panic("TclExecuteByteCode: unrecognized opCode %u", *pc);
    } /* end of switch on opCode */

    /*
     * Division by zero in an expression. Control only reaches this point by
     * "goto divideByZero".
     */

 divideByZero:
    Tcl_SetObjResult(interp, Tcl_NewStringObj("divide by zero", -1));
    Tcl_SetErrorCode(interp, "ARITH", "DIVZERO", "divide by zero", NULL);

    result = TCL_ERROR;
    goto checkForCatch;

    /*
     * Exponentiation of zero by negative number in an expression. Control
     * only reaches this point by "goto exponOfZero".
     */

 exponOfZero:
    Tcl_SetObjResult(interp, Tcl_NewStringObj(
            "exponentiation of zero by negative power", -1));
    Tcl_SetErrorCode(interp, "ARITH", "DOMAIN",
            "exponentiation of zero by negative power", NULL);
    result = TCL_ERROR;
    goto checkForCatch;

    /*
     * Block for variables needed to process exception returns.
     */

    {
        ExceptionRange *rangePtr;
                                /* Points to closest loop or catch exception
                                 * range enclosing the pc. Used by various
                                 * instructions and processCatch to process
                                 * break, continue, and errors. */
        Tcl_Obj *valuePtr;
        const char *bytes;
        int length;
#if TCL_COMPILE_DEBUG
        int opnd;
#endif

        /*
         * An external evaluation (INST_INVOKE or INST_EVAL) returned
         * something different from TCL_OK, or else INST_BREAK or
         * INST_CONTINUE were called.
         */

    processExceptionReturn:
#if TCL_COMPILE_DEBUG
        switch (*pc) {
        case INST_INVOKE_STK1:
            opnd = TclGetUInt1AtPtr(pc+1);
            TRACE(("%u => ... after \"%.20s\": ", opnd, cmdNameBuf));
            break;
        case INST_INVOKE_STK4:
            opnd = TclGetUInt4AtPtr(pc+1);
            TRACE(("%u => ... after \"%.20s\": ", opnd, cmdNameBuf));
            break;
        case INST_EVAL_STK:
            /*
             * Note that the object at stacktop has to be used before doing
             * the cleanup.
             */

            TRACE(("\"%.30s\" => ", O2S(OBJ_AT_TOS)));
            break;
        default:
            TRACE(("=> "));
        }
#endif
        if ((result == TCL_CONTINUE) || (result == TCL_BREAK)) {
            rangePtr = GetExceptRangeForPc(pc, /*catchOnly*/ 0, codePtr);
            if (rangePtr == NULL) {
                TRACE_APPEND(("no encl. loop or catch, returning %s\n",
                        StringForResultCode(result)));
                goto abnormalReturn;
            }
            if (rangePtr->type == CATCH_EXCEPTION_RANGE) {
                TRACE_APPEND(("%s ...\n", StringForResultCode(result)));
                goto processCatch;
            }
            while (cleanup--) {
                valuePtr = POP_OBJECT();
                TclDecrRefCount(valuePtr);
            }
            if (result == TCL_BREAK) {
                result = TCL_OK;
                pc = (codePtr->codeStart + rangePtr->breakOffset);
                TRACE_APPEND(("%s, range at %d, new pc %d\n",
                        StringForResultCode(result),
                        rangePtr->codeOffset, rangePtr->breakOffset));
                NEXT_INST_F(0, 0, 0);
            } else {
                if (rangePtr->continueOffset == -1) {
                    TRACE_APPEND((
                            "%s, loop w/o continue, checking for catch\n",
                            StringForResultCode(result)));
                    goto checkForCatch;
                }
                result = TCL_OK;
                pc = (codePtr->codeStart + rangePtr->continueOffset);
                TRACE_APPEND(("%s, range at %d, new pc %d\n",
                        StringForResultCode(result),
                        rangePtr->codeOffset, rangePtr->continueOffset));
                NEXT_INST_F(0, 0, 0);
            }
#if TCL_COMPILE_DEBUG
        } else if (traceInstructions) {
            if ((result != TCL_ERROR) && (result != TCL_RETURN)) {
                Tcl_Obj *objPtr = Tcl_GetObjResult(interp);
                TRACE_APPEND(("OTHER RETURN CODE %d, result= \"%s\"\n ",
                        result, O2S(objPtr)));
            } else {
                Tcl_Obj *objPtr = Tcl_GetObjResult(interp);
                TRACE_APPEND(("%s, result= \"%s\"\n",
                        StringForResultCode(result), O2S(objPtr)));
            }
#endif
        }

        /*
         * Execution has generated an "exception" such as TCL_ERROR. If the
         * exception is an error, record information about what was being
         * executed when the error occurred. Find the closest enclosing catch
         * range, if any. If no enclosing catch range is found, stop execution
         * and return the "exception" code.
         */

        checkForCatch:
        if ((result == TCL_ERROR) && !(iPtr->flags & ERR_ALREADY_LOGGED)) {
            bytes = GetSrcInfoForPc(pc, codePtr, &length);
            if (bytes != NULL) {
                DECACHE_STACK_INFO();
                Tcl_LogCommandInfo(interp, codePtr->source, bytes, length);
                CACHE_STACK_INFO();
            }
        }
        iPtr->flags &= ~ERR_ALREADY_LOGGED;

        /*
         * Clear all expansions that may have started after the last
         * INST_BEGIN_CATCH.
         */

        while ((expandNestList != NULL) && ((catchTop == initCatchTop) ||
                (*catchTop <=
                (ptrdiff_t) expandNestList->internalRep.twoPtrValue.ptr1))) {
            Tcl_Obj *objPtr = expandNestList->internalRep.twoPtrValue.ptr2;

            TclDecrRefCount(expandNestList);
            expandNestList = objPtr;
        }

        /*
         * We must not catch an exceeded limit. Instead, it blows outwards
         * until we either hit another interpreter (presumably where the limit
         * is not exceeded) or we get to the top-level.
         */

        if (TclLimitExceeded(iPtr->limit)) {
#ifdef TCL_COMPILE_DEBUG
            if (traceInstructions) {
                fprintf(stdout, "   ... limit exceeded, returning %s\n",
                        StringForResultCode(result));
            }
#endif
            goto abnormalReturn;
        }
        if (catchTop == initCatchTop) {
#ifdef TCL_COMPILE_DEBUG
            if (traceInstructions) {
                fprintf(stdout, "   ... no enclosing catch, returning %s\n",
                        StringForResultCode(result));
            }
#endif
            goto abnormalReturn;
        }
        rangePtr = GetExceptRangeForPc(pc, /*catchOnly*/ 1, codePtr);
        if (rangePtr == NULL) {
            /*
             * This is only possible when compiling a [catch] that sends its
             * script to INST_EVAL. Cannot correct the compiler without
             * breakingcompat with previous .tbc compiled scripts.
             */

#ifdef TCL_COMPILE_DEBUG
            if (traceInstructions) {
                fprintf(stdout, "   ... no enclosing catch, returning %s\n",
                        StringForResultCode(result));
            }
#endif
            goto abnormalReturn;
        }

        /*
         * A catch exception range (rangePtr) was found to handle an
         * "exception". It was found either by checkForCatch just above or by
         * an instruction during break, continue, or error processing. Jump to
         * its catchOffset after unwinding the operand stack to the depth it
         * had when starting to execute the range's catch command.
         */

    processCatch:
        while (CURR_DEPTH > *catchTop) {
            valuePtr = POP_OBJECT();
            TclDecrRefCount(valuePtr);
        }
#ifdef TCL_COMPILE_DEBUG
        if (traceInstructions) {
            fprintf(stdout, "  ... found catch at %d, catchTop=%d, "
                    "unwound to %ld, new pc %u\n",
                    rangePtr->codeOffset, catchTop - initCatchTop - 1,
                    (long) *catchTop, (unsigned) rangePtr->catchOffset);
        }
#endif
        pc = (codePtr->codeStart + rangePtr->catchOffset);
        NEXT_INST_F(0, 0, 0);   /* Restart the execution loop at pc. */

        /*
         * end of infinite loop dispatching on instructions.
         */

        /*
         * Abnormal return code. Restore the stack to state it had when
         * starting to execute the ByteCode. Panic if the stack is below the
         * initial level.
         */

    abnormalReturn:
        TCL_DTRACE_INST_LAST();
        while (tosPtr > initTosPtr) {
            Tcl_Obj *objPtr = POP_OBJECT();

            Tcl_DecrRefCount(objPtr);
        }

        /*
         * Clear all expansions.
         */

        while (expandNestList) {
            Tcl_Obj *objPtr = expandNestList->internalRep.twoPtrValue.ptr2;

            TclDecrRefCount(expandNestList);
            expandNestList = objPtr;
        }
        if (tosPtr < initTosPtr) {
            fprintf(stderr,
                    "\nTclExecuteByteCode: abnormal return at pc %u: "
                    "stack top %d < entry stack top %d\n",
                    (unsigned)(pc - codePtr->codeStart),
                    (unsigned) CURR_DEPTH, (unsigned) 0);
            Tcl_Panic("TclExecuteByteCode execution failure: end stack top < start stack top");
        }
    }

    /*
     * Restore the stack to the state it had previous to this bytecode.
     */

    TclStackFree(interp, initCatchTop+1);
    return result;
#undef iPtr
}

#ifdef TCL_COMPILE_DEBUG
/*
 *----------------------------------------------------------------------
 *
 * PrintByteCodeInfo --
 *
 *      This procedure prints a summary about a bytecode object to stdout. It
 *      is called by TclExecuteByteCode when starting to execute the bytecode
 *      object if tclTraceExec has the value 2 or more.
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      None.
 *
 *----------------------------------------------------------------------
 */

static void
PrintByteCodeInfo(
    register ByteCode *codePtr) /* The bytecode whose summary is printed to
                                 * stdout. */
{
    Proc *procPtr = codePtr->procPtr;
    Interp *iPtr = (Interp *) *codePtr->interpHandle;

    fprintf(stdout, "\nExecuting ByteCode 0x%p, refCt %u, epoch %u, interp 0x%p (epoch %u)\n",
            codePtr, codePtr->refCount, codePtr->compileEpoch, iPtr,
            iPtr->compileEpoch);

    fprintf(stdout, "  Source: ");
    TclPrintSource(stdout, codePtr->source, 60);

    fprintf(stdout, "\n  Cmds %d, src %d, inst %u, litObjs %u, aux %d, stkDepth %u, code/src %.2f\n",
            codePtr->numCommands, codePtr->numSrcBytes,
            codePtr->numCodeBytes, codePtr->numLitObjects,
            codePtr->numAuxDataItems, codePtr->maxStackDepth,
#ifdef TCL_COMPILE_STATS
            codePtr->numSrcBytes?
                    ((float)codePtr->structureSize)/codePtr->numSrcBytes :
#endif
            0.0);

#ifdef TCL_COMPILE_STATS
    fprintf(stdout, "  Code %lu = header %lu+inst %d+litObj %lu+exc %lu+aux %lu+cmdMap %d\n",
            (unsigned long) codePtr->structureSize,
            (unsigned long) (sizeof(ByteCode)-sizeof(size_t)-sizeof(Tcl_Time)),
            codePtr->numCodeBytes,
            (unsigned long) (codePtr->numLitObjects * sizeof(Tcl_Obj *)),
            (unsigned long) (codePtr->numExceptRanges*sizeof(ExceptionRange)),
            (unsigned long) (codePtr->numAuxDataItems * sizeof(AuxData)),
            codePtr->numCmdLocBytes);
#endif /* TCL_COMPILE_STATS */
    if (procPtr != NULL) {
        fprintf(stdout,
                "  Proc 0x%p, refCt %d, args %d, compiled locals %d\n",
                procPtr, procPtr->refCount, procPtr->numArgs,
                procPtr->numCompiledLocals);
    }
}
#endif /* TCL_COMPILE_DEBUG */

/*
 *----------------------------------------------------------------------
 *
 * ValidatePcAndStackTop --
 *
 *      This procedure is called by TclExecuteByteCode when debugging to
 *      verify that the program counter and stack top are valid during
 *      execution.
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      Prints a message to stderr and panics if either the pc or stack top
 *      are invalid.
 *
 *----------------------------------------------------------------------
 */

#ifdef TCL_COMPILE_DEBUG
static void
ValidatePcAndStackTop(
    register ByteCode *codePtr, /* The bytecode whose summary is printed to
                                 * stdout. */
    unsigned char *pc,          /* Points to first byte of a bytecode
                                 * instruction. The program counter. */
    int stackTop,               /* Current stack top. Must be between
                                 * stackLowerBound and stackUpperBound
                                 * (inclusive). */
    int stackLowerBound,        /* Smallest legal value for stackTop. */
    int checkStack)             /* 0 if the stack depth check should be
                                 * skipped. */
{
    int stackUpperBound = stackLowerBound + codePtr->maxStackDepth;
                                /* Greatest legal value for stackTop. */
    unsigned relativePc = (unsigned) (pc - codePtr->codeStart);
    unsigned long codeStart = (unsigned long) codePtr->codeStart;
    unsigned long codeEnd = (unsigned long)
            (codePtr->codeStart + codePtr->numCodeBytes);
    unsigned char opCode = *pc;

    if (((unsigned long) pc < codeStart) || ((unsigned long) pc > codeEnd)) {
        fprintf(stderr, "\nBad instruction pc 0x%p in TclExecuteByteCode\n",
                pc);
        Tcl_Panic("TclExecuteByteCode execution failure: bad pc");
    }
    if ((unsigned) opCode > LAST_INST_OPCODE) {
        fprintf(stderr, "\nBad opcode %d at pc %u in TclExecuteByteCode\n",
                (unsigned) opCode, relativePc);
        Tcl_Panic("TclExecuteByteCode execution failure: bad opcode");
    }
    if (checkStack &&
            ((stackTop < stackLowerBound) || (stackTop > stackUpperBound))) {
        int numChars;
        const char *cmd = GetSrcInfoForPc(pc, codePtr, &numChars);

        fprintf(stderr, "\nBad stack top %d at pc %u in TclExecuteByteCode (min %i, max %i)",
                stackTop, relativePc, stackLowerBound, stackUpperBound);
        if (cmd != NULL) {
            Tcl_Obj *message;

            TclNewLiteralStringObj(message, "\n executing ");
            Tcl_IncrRefCount(message);
            Tcl_AppendLimitedToObj(message, cmd, numChars, 100, NULL);
            fprintf(stderr,"%s\n", Tcl_GetString(message));
            Tcl_DecrRefCount(message);
        } else {
            fprintf(stderr, "\n");
        }
        Tcl_Panic("TclExecuteByteCode execution failure: bad stack top");
    }
}
#endif /* TCL_COMPILE_DEBUG */

/*
 *----------------------------------------------------------------------
 *
 * IllegalExprOperandType --
 *
 *      Used by TclExecuteByteCode to append an error message to the interp
 *      result when an illegal operand type is detected by an expression
 *      instruction. The argument opndPtr holds the operand object in error.
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      An error message is appended to the interp result.
 *
 *----------------------------------------------------------------------
 */

static void
IllegalExprOperandType(
    Tcl_Interp *interp,         /* Interpreter to which error information
                                 * pertains. */
    unsigned char *pc,          /* Points to the instruction being executed
                                 * when the illegal type was found. */
    Tcl_Obj *opndPtr)           /* Points to the operand holding the value
                                 * with the illegal type. */
{
    ClientData ptr;
    int type;
    unsigned char opcode = *pc;
    const char *description, *operator = operatorStrings[opcode - INST_LOR];

    if (opcode == INST_EXPON) {
        operator = "**";
    }

    if (GetNumberFromObj(NULL, opndPtr, &ptr, &type) != TCL_OK) {
        int numBytes;
        const char *bytes = Tcl_GetStringFromObj(opndPtr, &numBytes);

        if (numBytes == 0) {
            description = "empty string";
        } else if (TclCheckBadOctal(NULL, bytes)) {
            description = "invalid octal number";
        } else {
            description = "non-numeric string";
        }
    } else if (type == TCL_NUMBER_NAN) {
        description = "non-numeric floating-point value";
    } else if (type == TCL_NUMBER_DOUBLE) {
        description = "floating-point value";
    } else {
        /* TODO: No caller needs this. Eliminate? */
        description = "(big) integer";
    }

    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
            "can't use %s as operand of \"%s\"", description, operator));
}

/*
 *----------------------------------------------------------------------
 *
 * TclGetSrcInfoForPc, GetSrcInfoForPc, TclGetSrcInfoForCmd --
 *
 *      Given a program counter value, finds the closest command in the
 *      bytecode code unit's CmdLocation array and returns information about
 *      that command's source: a pointer to its first byte and the number of
 *      characters.
 *
 * Results:
 *      If a command is found that encloses the program counter value, a
 *      pointer to the command's source is returned and the length of the
 *      source is stored at *lengthPtr. If multiple commands resulted in code
 *      at pc, information about the closest enclosing command is returned. If
 *      no matching command is found, NULL is returned and *lengthPtr is
 *      unchanged.
 *
 * Side effects:
 *      The CmdFrame at *cfPtr is updated.
 *
 *----------------------------------------------------------------------
 */

const char *
TclGetSrcInfoForCmd(
    Interp *iPtr,
    int *lenPtr)
{
    CmdFrame *cfPtr = iPtr->cmdFramePtr;
    ByteCode *codePtr = (ByteCode *) cfPtr->data.tebc.codePtr;

    return GetSrcInfoForPc((unsigned char *) cfPtr->data.tebc.pc,
            codePtr, lenPtr);
}

void
TclGetSrcInfoForPc(
    CmdFrame *cfPtr)
{
    ByteCode *codePtr = (ByteCode *) cfPtr->data.tebc.codePtr;

    if (cfPtr->cmd.str.cmd == NULL) {
        cfPtr->cmd.str.cmd = GetSrcInfoForPc(
                (unsigned char *) cfPtr->data.tebc.pc, codePtr,
                &cfPtr->cmd.str.len);
    }

    if (cfPtr->cmd.str.cmd != NULL) {
        /*
         * We now have the command. We can get the srcOffset back and from
         * there find the list of word locations for this command.
         */

        ExtCmdLoc *eclPtr;
        ECL *locPtr = NULL;
        int srcOffset, i;
        Interp *iPtr = (Interp *) *codePtr->interpHandle;
        Tcl_HashEntry *hePtr =
                Tcl_FindHashEntry(iPtr->lineBCPtr, (char *) codePtr);

        if (!hePtr) {
            return;
        }

        srcOffset = cfPtr->cmd.str.cmd - codePtr->source;
        eclPtr = (ExtCmdLoc *) Tcl_GetHashValue (hePtr);

        for (i=0; i < eclPtr->nuloc; i++) {
            if (eclPtr->loc[i].srcOffset == srcOffset) {
                locPtr = eclPtr->loc+i;
                break;
            }
        }
        if (locPtr == NULL) {
            Tcl_Panic("LocSearch failure");
        }

        cfPtr->line = locPtr->line;
        cfPtr->nline = locPtr->nline;
        cfPtr->type = eclPtr->type;

        if (eclPtr->type == TCL_LOCATION_SOURCE) {
            cfPtr->data.eval.path = eclPtr->path;
            Tcl_IncrRefCount(cfPtr->data.eval.path);
        }

        /*
         * Do not set cfPtr->data.eval.path NULL for non-SOURCE. Needed for
         * cfPtr->data.tebc.codePtr.
         */
    }
}

static const char *
GetSrcInfoForPc(
    unsigned char *pc,          /* The program counter value for which to
                                 * return the closest command's source info.
                                 * This points to a bytecode instruction in
                                 * codePtr's code. */
    ByteCode *codePtr,          /* The bytecode sequence in which to look up
                                 * the command source for the pc. */
    int *lengthPtr)             /* If non-NULL, the location where the length
                                 * of the command's source should be stored.
                                 * If NULL, no length is stored. */
{
    register int pcOffset = (pc - codePtr->codeStart);
    int numCmds = codePtr->numCommands;
    unsigned char *codeDeltaNext, *codeLengthNext;
    unsigned char *srcDeltaNext, *srcLengthNext;
    int codeOffset, codeLen, codeEnd, srcOffset, srcLen, delta, i;
    int bestDist = INT_MAX;     /* Distance of pc to best cmd's start pc. */
    int bestSrcOffset = -1;     /* Initialized to avoid compiler warning. */
    int bestSrcLength = -1;     /* Initialized to avoid compiler warning. */

    if ((pcOffset < 0) || (pcOffset >= codePtr->numCodeBytes)) {
        return NULL;
    }

    /*
     * Decode the code and source offset and length for each command. The
     * closest enclosing command is the last one whose code started before
     * pcOffset.
     */

    codeDeltaNext = codePtr->codeDeltaStart;
    codeLengthNext = codePtr->codeLengthStart;
    srcDeltaNext = codePtr->srcDeltaStart;
    srcLengthNext = codePtr->srcLengthStart;
    codeOffset = srcOffset = 0;
    for (i = 0;  i < numCmds;  i++) {
        if ((unsigned) *codeDeltaNext == (unsigned) 0xFF) {
            codeDeltaNext++;
            delta = TclGetInt4AtPtr(codeDeltaNext);
            codeDeltaNext += 4;
        } else {
            delta = TclGetInt1AtPtr(codeDeltaNext);
            codeDeltaNext++;
        }
        codeOffset += delta;

        if ((unsigned) *codeLengthNext == (unsigned) 0xFF) {
            codeLengthNext++;
            codeLen = TclGetInt4AtPtr(codeLengthNext);
            codeLengthNext += 4;
        } else {
            codeLen = TclGetInt1AtPtr(codeLengthNext);
            codeLengthNext++;
        }
        codeEnd = (codeOffset + codeLen - 1);

        if ((unsigned) *srcDeltaNext == (unsigned) 0xFF) {
            srcDeltaNext++;
            delta = TclGetInt4AtPtr(srcDeltaNext);
            srcDeltaNext += 4;
        } else {
            delta = TclGetInt1AtPtr(srcDeltaNext);
            srcDeltaNext++;
        }
        srcOffset += delta;

        if ((unsigned) *srcLengthNext == (unsigned) 0xFF) {
            srcLengthNext++;
            srcLen = TclGetInt4AtPtr(srcLengthNext);
            srcLengthNext += 4;
        } else {
            srcLen = TclGetInt1AtPtr(srcLengthNext);
            srcLengthNext++;
        }

        if (codeOffset > pcOffset) {    /* Best cmd already found */
            break;
        }
        if (pcOffset <= codeEnd) {      /* This cmd's code encloses pc */
            int dist = (pcOffset - codeOffset);

            if (dist <= bestDist) {
                bestDist = dist;
                bestSrcOffset = srcOffset;
                bestSrcLength = srcLen;
            }
        }
    }

    if (bestDist == INT_MAX) {
        return NULL;
    }

    if (lengthPtr != NULL) {
        *lengthPtr = bestSrcLength;
    }
    return (codePtr->source + bestSrcOffset);
}

/*
 *----------------------------------------------------------------------
 *
 * GetExceptRangeForPc --
 *
 *      Given a program counter value, return the closest enclosing
 *      ExceptionRange.
 *
 * Results:
 *      In the normal case, catchOnly is 0 (false) and this procedure returns
 *      a pointer to the most closely enclosing ExceptionRange structure
 *      regardless of whether it is a loop or catch exception range. This is
 *      appropriate when processing a TCL_BREAK or TCL_CONTINUE, which will be
 *      "handled" either by a loop exception range or a closer catch range. If
 *      catchOnly is nonzero, this procedure ignores loop exception ranges and
 *      returns a pointer to the closest catch range. If no matching
 *      ExceptionRange is found that encloses pc, a NULL is returned.
 *
 * Side effects:
 *      None.
 *
 *----------------------------------------------------------------------
 */

static ExceptionRange *
GetExceptRangeForPc(
    unsigned char *pc,          /* The program counter value for which to
                                 * search for a closest enclosing exception
                                 * range. This points to a bytecode
                                 * instruction in codePtr's code. */
    int catchOnly,              /* If 0, consider either loop or catch
                                 * ExceptionRanges in search. If nonzero
                                 * consider only catch ranges (and ignore any
                                 * closer loop ranges). */
    ByteCode *codePtr)          /* Points to the ByteCode in which to search
                                 * for the enclosing ExceptionRange. */
{
    ExceptionRange *rangeArrayPtr;
    int numRanges = codePtr->numExceptRanges;
    register ExceptionRange *rangePtr;
    int pcOffset = pc - codePtr->codeStart;
    register int start;

    if (numRanges == 0) {
        return NULL;
    }

    /*
     * This exploits peculiarities of our compiler: nested ranges are always
     * *after* their containing ranges, so that by scanning backwards we are
     * sure that the first matching range is indeed the deepest.
     */

    rangeArrayPtr = codePtr->exceptArrayPtr;
    rangePtr = rangeArrayPtr + numRanges;
    while (--rangePtr >= rangeArrayPtr) {
        start = rangePtr->codeOffset;
        if ((start <= pcOffset) &&
                (pcOffset < (start + rangePtr->numCodeBytes))) {
            if ((!catchOnly)
                    || (rangePtr->type == CATCH_EXCEPTION_RANGE)) {
                return rangePtr;
            }
        }
    }
    return NULL;
}

/*
 *----------------------------------------------------------------------
 *
 * GetOpcodeName --
 *
 *      This procedure is called by the TRACE and TRACE_WITH_OBJ macros used
 *      in TclExecuteByteCode when debugging. It returns the name of the
 *      bytecode instruction at a specified instruction pc.
 *
 * Results:
 *      A character string for the instruction.
 *
 * Side effects:
 *      None.
 *
 *----------------------------------------------------------------------
 */

#ifdef TCL_COMPILE_DEBUG
static char *
GetOpcodeName(
    unsigned char *pc)          /* Points to the instruction whose name should
                                 * be returned. */
{
    unsigned char opCode = *pc;

    return tclInstructionTable[opCode].name;
}
#endif /* TCL_COMPILE_DEBUG */

/*
 *----------------------------------------------------------------------
 *
 * TclExprFloatError --
 *
 *      This procedure is called when an error occurs during a floating-point
 *      operation. It reads errno and sets interp->objResultPtr accordingly.
 *
 * Results:
 *      interp->objResultPtr is set to hold an error message.
 *
 * Side effects:
 *      None.
 *
 *----------------------------------------------------------------------
 */

void
TclExprFloatError(
    Tcl_Interp *interp,         /* Where to store error message. */
    double value)               /* Value returned after error; used to
                                 * distinguish underflows from overflows. */
{
    const char *s;

    if ((errno == EDOM) || TclIsNaN(value)) {
        s = "domain error: argument not in valid range";
        Tcl_SetObjResult(interp, Tcl_NewStringObj(s, -1));
        Tcl_SetErrorCode(interp, "ARITH", "DOMAIN", s, NULL);
    } else if ((errno == ERANGE) || TclIsInfinite(value)) {
        if (value == 0.0) {
            s = "floating-point value too small to represent";
            Tcl_SetObjResult(interp, Tcl_NewStringObj(s, -1));
            Tcl_SetErrorCode(interp, "ARITH", "UNDERFLOW", s, NULL);
        } else {
            s = "floating-point value too large to represent";
            Tcl_SetObjResult(interp, Tcl_NewStringObj(s, -1));
            Tcl_SetErrorCode(interp, "ARITH", "OVERFLOW", s, NULL);
        }
    } else {
        Tcl_Obj *objPtr = Tcl_ObjPrintf(
                "unknown floating-point error, errno = %d", errno);

        Tcl_SetErrorCode(interp, "ARITH", "UNKNOWN",
                Tcl_GetString(objPtr), NULL);
        Tcl_SetObjResult(interp, objPtr);
    }
}

#ifdef TCL_COMPILE_STATS
/*
 *----------------------------------------------------------------------
 *
 * TclLog2 --
 *
 *      Procedure used while collecting compilation statistics to determine
 *      the log base 2 of an integer.
 *
 * Results:
 *      Returns the log base 2 of the operand. If the argument is less than or
 *      equal to zero, a zero is returned.
 *
 * Side effects:
 *      None.
 *
 *----------------------------------------------------------------------
 */

int
TclLog2(
    register int value)         /* The integer for which to compute the log
                                 * base 2. */
{
    register int n = value;
    register int result = 0;

    while (n > 1) {
        n = n >> 1;
        result++;
    }
    return result;
}

/*
 *----------------------------------------------------------------------
 *
 * EvalStatsCmd --
 *
 *      Implements the "evalstats" command that prints instruction execution
 *      counts to stdout.
 *
 * Results:
 *      Standard Tcl results.
 *
 * Side effects:
 *      None.
 *
 *----------------------------------------------------------------------
 */

static int
EvalStatsCmd(
    ClientData unused,          /* Unused. */
    Tcl_Interp *interp,         /* The current interpreter. */
    int objc,                   /* The number of arguments. */
    Tcl_Obj *const objv[])      /* The argument strings. */
{
    Interp *iPtr = (Interp *) interp;
    LiteralTable *globalTablePtr = &iPtr->literalTable;
    ByteCodeStats *statsPtr = &iPtr->stats;
    double totalCodeBytes, currentCodeBytes;
    double totalLiteralBytes, currentLiteralBytes;
    double objBytesIfUnshared, strBytesIfUnshared, sharingBytesSaved;
    double strBytesSharedMultX, strBytesSharedOnce;
    double numInstructions, currentHeaderBytes;
    long numCurrentByteCodes, numByteCodeLits;
    long refCountSum, literalMgmtBytes, sum;
    int numSharedMultX, numSharedOnce;
    int decadeHigh, minSizeDecade, maxSizeDecade, length, i;
    char *litTableStats;
    LiteralEntry *entryPtr;

#define Percent(a,b) ((a) * 100.0 / (b))

    numInstructions = 0.0;
    for (i = 0;  i < 256;  i++) {
        if (statsPtr->instructionCount[i] != 0) {
            numInstructions += statsPtr->instructionCount[i];
        }
    }

    totalLiteralBytes = sizeof(LiteralTable)
            + iPtr->literalTable.numBuckets * sizeof(LiteralEntry *)
            + (statsPtr->numLiteralsCreated * sizeof(LiteralEntry))
            + (statsPtr->numLiteralsCreated * sizeof(Tcl_Obj))
            + statsPtr->totalLitStringBytes;
    totalCodeBytes = statsPtr->totalByteCodeBytes + totalLiteralBytes;

    numCurrentByteCodes =
            statsPtr->numCompilations - statsPtr->numByteCodesFreed;
    currentHeaderBytes = numCurrentByteCodes
            * (sizeof(ByteCode) - sizeof(size_t) - sizeof(Tcl_Time));
    literalMgmtBytes = sizeof(LiteralTable)
            + (iPtr->literalTable.numBuckets * sizeof(LiteralEntry *))
            + (iPtr->literalTable.numEntries * sizeof(LiteralEntry));
    currentLiteralBytes = literalMgmtBytes
            + iPtr->literalTable.numEntries * sizeof(Tcl_Obj)
            + statsPtr->currentLitStringBytes;
    currentCodeBytes = statsPtr->currentByteCodeBytes + currentLiteralBytes;

    /*
     * Summary statistics, total and current source and ByteCode sizes.
     */

    fprintf(stdout, "\n----------------------------------------------------------------\n");
    fprintf(stdout,
            "Compilation and execution statistics for interpreter 0x%p\n",
            iPtr);

    fprintf(stdout, "\nNumber ByteCodes executed        %ld\n",
            statsPtr->numExecutions);
    fprintf(stdout, "Number ByteCodes compiled  %ld\n",
            statsPtr->numCompilations);
    fprintf(stdout, "  Mean executions/compile  %.1f\n",
            statsPtr->numExecutions / (float)statsPtr->numCompilations);

    fprintf(stdout, "\nInstructions executed            %.0f\n",
            numInstructions);
    fprintf(stdout, "  Mean inst/compile                %.0f\n",
            numInstructions / statsPtr->numCompilations);
    fprintf(stdout, "  Mean inst/execution              %.0f\n",
            numInstructions / statsPtr->numExecutions);

    fprintf(stdout, "\nTotal ByteCodes                  %ld\n",
            statsPtr->numCompilations);
    fprintf(stdout, "  Source bytes                     %.6g\n",
            statsPtr->totalSrcBytes);
    fprintf(stdout, "  Code bytes                       %.6g\n",
            totalCodeBytes);
    fprintf(stdout, "    ByteCode bytes         %.6g\n",
            statsPtr->totalByteCodeBytes);
    fprintf(stdout, "    Literal bytes          %.6g\n",
            totalLiteralBytes);
    fprintf(stdout, "      table %lu + bkts %lu + entries %lu + objects %lu + strings %.6g\n",
            (unsigned long) sizeof(LiteralTable),
            (unsigned long) (iPtr->literalTable.numBuckets * sizeof(LiteralEntry *)),
            (unsigned long) (statsPtr->numLiteralsCreated * sizeof(LiteralEntry)),
            (unsigned long) (statsPtr->numLiteralsCreated * sizeof(Tcl_Obj)),
            statsPtr->totalLitStringBytes);
    fprintf(stdout, "  Mean code/compile                %.1f\n",
            totalCodeBytes / statsPtr->numCompilations);
    fprintf(stdout, "  Mean code/source         %.1f\n",
            totalCodeBytes / statsPtr->totalSrcBytes);

    fprintf(stdout, "\nCurrent (active) ByteCodes       %ld\n",
            numCurrentByteCodes);
    fprintf(stdout, "  Source bytes                     %.6g\n",
            statsPtr->currentSrcBytes);
    fprintf(stdout, "  Code bytes                       %.6g\n",
            currentCodeBytes);
    fprintf(stdout, "    ByteCode bytes         %.6g\n",
            statsPtr->currentByteCodeBytes);
    fprintf(stdout, "    Literal bytes          %.6g\n",
            currentLiteralBytes);
    fprintf(stdout, "      table %lu + bkts %lu + entries %lu + objects %lu + strings %.6g\n",
            (unsigned long) sizeof(LiteralTable),
            (unsigned long) (iPtr->literalTable.numBuckets * sizeof(LiteralEntry *)),
            (unsigned long) (iPtr->literalTable.numEntries * sizeof(LiteralEntry)),
            (unsigned long) (iPtr->literalTable.numEntries * sizeof(Tcl_Obj)),
            statsPtr->currentLitStringBytes);
    fprintf(stdout, "  Mean code/source         %.1f\n",
            currentCodeBytes / statsPtr->currentSrcBytes);
    fprintf(stdout, "  Code + source bytes              %.6g (%0.1f mean code/src)\n",
            (currentCodeBytes + statsPtr->currentSrcBytes),
            (currentCodeBytes / statsPtr->currentSrcBytes) + 1.0);

    /*
     * Tcl_IsShared statistics check
     *
     * This gives the refcount of each obj as Tcl_IsShared was called for it.
     * Shared objects must be duplicated before they can be modified.
     */

    numSharedMultX = 0;
    fprintf(stdout, "\nTcl_IsShared object check (all objects):\n");
    fprintf(stdout, "  Object had refcount <=1 (not shared)     %ld\n",
            tclObjsShared[1]);
    for (i = 2;  i < TCL_MAX_SHARED_OBJ_STATS;  i++) {
        fprintf(stdout, "  refcount ==%d                %ld\n",
                i, tclObjsShared[i]);
        numSharedMultX += tclObjsShared[i];
    }
    fprintf(stdout, "  refcount >=%d            %ld\n",
            i, tclObjsShared[0]);
    numSharedMultX += tclObjsShared[0];
    fprintf(stdout, "  Total shared objects                     %d\n",
            numSharedMultX);

    /*
     * Literal table statistics.
     */

    numByteCodeLits = 0;
    refCountSum = 0;
    numSharedMultX = 0;
    numSharedOnce = 0;
    objBytesIfUnshared = 0.0;
    strBytesIfUnshared = 0.0;
    strBytesSharedMultX = 0.0;
    strBytesSharedOnce = 0.0;
    for (i = 0;  i < globalTablePtr->numBuckets;  i++) {
        for (entryPtr = globalTablePtr->buckets[i];  entryPtr != NULL;
                entryPtr = entryPtr->nextPtr) {
            if (entryPtr->objPtr->typePtr == &tclByteCodeType) {
                numByteCodeLits++;
            }
            (void) Tcl_GetStringFromObj(entryPtr->objPtr, &length);
            refCountSum += entryPtr->refCount;
            objBytesIfUnshared += (entryPtr->refCount * sizeof(Tcl_Obj));
            strBytesIfUnshared += (entryPtr->refCount * (length+1));
            if (entryPtr->refCount > 1) {
                numSharedMultX++;
                strBytesSharedMultX += (length+1);
            } else {
                numSharedOnce++;
                strBytesSharedOnce += (length+1);
            }
        }
    }
    sharingBytesSaved = (objBytesIfUnshared + strBytesIfUnshared)
            - currentLiteralBytes;

    fprintf(stdout, "\nTotal objects (all interps)      %ld\n",
            tclObjsAlloced);
    fprintf(stdout, "Current objects                    %ld\n",
            (tclObjsAlloced - tclObjsFreed));
    fprintf(stdout, "Total literal objects              %ld\n",
            statsPtr->numLiteralsCreated);

    fprintf(stdout, "\nCurrent literal objects          %d (%0.1f%% of current objects)\n",
            globalTablePtr->numEntries,
            Percent(globalTablePtr->numEntries, tclObjsAlloced-tclObjsFreed));
    fprintf(stdout, "  ByteCode literals                %ld (%0.1f%% of current literals)\n",
            numByteCodeLits,
            Percent(numByteCodeLits, globalTablePtr->numEntries));
    fprintf(stdout, "  Literals reused > 1x             %d\n",
            numSharedMultX);
    fprintf(stdout, "  Mean reference count             %.2f\n",
            ((double) refCountSum) / globalTablePtr->numEntries);
    fprintf(stdout, "  Mean len, str reused >1x         %.2f\n",
            (numSharedMultX ? strBytesSharedMultX/numSharedMultX : 0.0));
    fprintf(stdout, "  Mean len, str used 1x            %.2f\n",
            (numSharedOnce ? strBytesSharedOnce/numSharedOnce : 0.0));
    fprintf(stdout, "  Total sharing savings            %.6g (%0.1f%% of bytes if no sharing)\n",
            sharingBytesSaved,
            Percent(sharingBytesSaved, objBytesIfUnshared+strBytesIfUnshared));
    fprintf(stdout, "    Bytes with sharing             %.6g\n",
            currentLiteralBytes);
    fprintf(stdout, "      table %lu + bkts %lu + entries %lu + objects %lu + strings %.6g\n",
            (unsigned long) sizeof(LiteralTable),
            (unsigned long) (iPtr->literalTable.numBuckets * sizeof(LiteralEntry *)),
            (unsigned long) (iPtr->literalTable.numEntries * sizeof(LiteralEntry)),
            (unsigned long) (iPtr->literalTable.numEntries * sizeof(Tcl_Obj)),
            statsPtr->currentLitStringBytes);
    fprintf(stdout, "    Bytes if no sharing            %.6g = objects %.6g + strings %.6g\n",
            (objBytesIfUnshared + strBytesIfUnshared),
            objBytesIfUnshared, strBytesIfUnshared);
    fprintf(stdout, "  String sharing savings   %.6g = unshared %.6g - shared %.6g\n",
            (strBytesIfUnshared - statsPtr->currentLitStringBytes),
            strBytesIfUnshared, statsPtr->currentLitStringBytes);
    fprintf(stdout, "  Literal mgmt overhead            %ld (%0.1f%% of bytes with sharing)\n",
            literalMgmtBytes,
            Percent(literalMgmtBytes, currentLiteralBytes));
    fprintf(stdout, "    table %lu + buckets %lu + entries %lu\n",
            (unsigned long) sizeof(LiteralTable),
            (unsigned long) (iPtr->literalTable.numBuckets * sizeof(LiteralEntry *)),
            (unsigned long) (iPtr->literalTable.numEntries * sizeof(LiteralEntry)));

    /*
     * Breakdown of current ByteCode space requirements.
     */

    fprintf(stdout, "\nBreakdown of current ByteCode requirements:\n");
    fprintf(stdout, "                         Bytes      Pct of    Avg per\n");
    fprintf(stdout, "                                     total    ByteCode\n");
    fprintf(stdout, "Total             %12.6g     100.00%%   %8.1f\n",
            statsPtr->currentByteCodeBytes,
            statsPtr->currentByteCodeBytes / numCurrentByteCodes);
    fprintf(stdout, "Header            %12.6g   %8.1f%%   %8.1f\n",
            currentHeaderBytes,
            Percent(currentHeaderBytes, statsPtr->currentByteCodeBytes),
            currentHeaderBytes / numCurrentByteCodes);
    fprintf(stdout, "Instructions      %12.6g   %8.1f%%   %8.1f\n",
            statsPtr->currentInstBytes,
            Percent(statsPtr->currentInstBytes,statsPtr->currentByteCodeBytes),
            statsPtr->currentInstBytes / numCurrentByteCodes);
    fprintf(stdout, "Literal ptr array %12.6g   %8.1f%%   %8.1f\n",
            statsPtr->currentLitBytes,
            Percent(statsPtr->currentLitBytes,statsPtr->currentByteCodeBytes),
            statsPtr->currentLitBytes / numCurrentByteCodes);
    fprintf(stdout, "Exception table   %12.6g   %8.1f%%   %8.1f\n",
            statsPtr->currentExceptBytes,
            Percent(statsPtr->currentExceptBytes,statsPtr->currentByteCodeBytes),
            statsPtr->currentExceptBytes / numCurrentByteCodes);
    fprintf(stdout, "Auxiliary data    %12.6g   %8.1f%%   %8.1f\n",
            statsPtr->currentAuxBytes,
            Percent(statsPtr->currentAuxBytes,statsPtr->currentByteCodeBytes),
            statsPtr->currentAuxBytes / numCurrentByteCodes);
    fprintf(stdout, "Command map       %12.6g   %8.1f%%   %8.1f\n",
            statsPtr->currentCmdMapBytes,
            Percent(statsPtr->currentCmdMapBytes,statsPtr->currentByteCodeBytes),
            statsPtr->currentCmdMapBytes / numCurrentByteCodes);

    /*
     * Detailed literal statistics.
     */

    fprintf(stdout, "\nLiteral string sizes:\n");
    fprintf(stdout, "    Up to length           Percentage\n");
    maxSizeDecade = 0;
    for (i = 31;  i >= 0;  i--) {
        if (statsPtr->literalCount[i] > 0) {
            maxSizeDecade = i;
            break;
        }
    }
    sum = 0;
    for (i = 0;  i <= maxSizeDecade;  i++) {
        decadeHigh = (1 << (i+1)) - 1;
        sum += statsPtr->literalCount[i];
        fprintf(stdout, "       %10d            %8.0f%%\n",
                decadeHigh, Percent(sum, statsPtr->numLiteralsCreated));
    }

    litTableStats = TclLiteralStats(globalTablePtr);
    fprintf(stdout, "\nCurrent literal table statistics:\n%s\n",
            litTableStats);
    ckfree((char *) litTableStats);

    /*
     * Source and ByteCode size distributions.
     */

    fprintf(stdout, "\nSource sizes:\n");
    fprintf(stdout, "    Up to size             Percentage\n");
    minSizeDecade = maxSizeDecade = 0;
    for (i = 0;  i < 31;  i++) {
        if (statsPtr->srcCount[i] > 0) {
            minSizeDecade = i;
            break;
        }
    }
    for (i = 31;  i >= 0;  i--) {
        if (statsPtr->srcCount[i] > 0) {
            maxSizeDecade = i;
            break;
        }
    }
    sum = 0;
    for (i = minSizeDecade;  i <= maxSizeDecade;  i++) {
        decadeHigh = (1 << (i+1)) - 1;
        sum += statsPtr->srcCount[i];
        fprintf(stdout, "       %10d            %8.0f%%\n",
                decadeHigh, Percent(sum, statsPtr->numCompilations));
    }

    fprintf(stdout, "\nByteCode sizes:\n");
    fprintf(stdout, "    Up to size             Percentage\n");
    minSizeDecade = maxSizeDecade = 0;
    for (i = 0;  i < 31;  i++) {
        if (statsPtr->byteCodeCount[i] > 0) {
            minSizeDecade = i;
            break;
        }
    }
    for (i = 31;  i >= 0;  i--) {
        if (statsPtr->byteCodeCount[i] > 0) {
            maxSizeDecade = i;
            break;
        }
    }
    sum = 0;
    for (i = minSizeDecade;  i <= maxSizeDecade;  i++) {
        decadeHigh = (1 << (i+1)) - 1;
        sum += statsPtr->byteCodeCount[i];
        fprintf(stdout, "       %10d            %8.0f%%\n",
                decadeHigh, Percent(sum, statsPtr->numCompilations));
    }

    fprintf(stdout, "\nByteCode longevity (excludes Current ByteCodes):\n");
    fprintf(stdout, "          Up to ms         Percentage\n");
    minSizeDecade = maxSizeDecade = 0;
    for (i = 0;  i < 31;  i++) {
        if (statsPtr->lifetimeCount[i] > 0) {
            minSizeDecade = i;
            break;
        }
    }
    for (i = 31;  i >= 0;  i--) {
        if (statsPtr->lifetimeCount[i] > 0) {
            maxSizeDecade = i;
            break;
        }
    }
    sum = 0;
    for (i = minSizeDecade;  i <= maxSizeDecade;  i++) {
        decadeHigh = (1 << (i+1)) - 1;
        sum += statsPtr->lifetimeCount[i];
        fprintf(stdout, "       %12.3f          %8.0f%%\n",
                decadeHigh/1000.0, Percent(sum, statsPtr->numByteCodesFreed));
    }

    /*
     * Instruction counts.
     */

    fprintf(stdout, "\nInstruction counts:\n");
    for (i = 0;  i <= LAST_INST_OPCODE;  i++) {
        if (statsPtr->instructionCount[i] == 0) {
            fprintf(stdout, "%20s %8ld %6.1f%%\n",
                    tclInstructionTable[i].name,
                    statsPtr->instructionCount[i],
                    Percent(statsPtr->instructionCount[i], numInstructions));
        }
    }

    fprintf(stdout, "\nInstructions NEVER executed:\n");
    for (i = 0;  i <= LAST_INST_OPCODE;  i++) {
        if (statsPtr->instructionCount[i] == 0) {
            fprintf(stdout, "%20s\n", tclInstructionTable[i].name);
        }
    }

#ifdef TCL_MEM_DEBUG
    fprintf(stdout, "\nHeap Statistics:\n");
    TclDumpMemoryInfo(stdout);
#endif
    fprintf(stdout, "\n----------------------------------------------------------------\n");
    return TCL_OK;
}
#endif /* TCL_COMPILE_STATS */

#ifdef TCL_COMPILE_DEBUG
/*
 *----------------------------------------------------------------------
 *
 * StringForResultCode --
 *
 *      Procedure that returns a human-readable string representing a Tcl
 *      result code such as TCL_ERROR.
 *
 * Results:
 *      If the result code is one of the standard Tcl return codes, the result
 *      is a string representing that code such as "TCL_ERROR". Otherwise, the
 *      result string is that code formatted as a sequence of decimal digit
 *      characters. Note that the resulting string must not be modified by the
 *      caller.
 *
 * Side effects:
 *      None.
 *
 *----------------------------------------------------------------------
 */

static const char *
StringForResultCode(
    int result)                 /* The Tcl result code for which to generate a
                                 * string. */
{
    static char buf[TCL_INTEGER_SPACE];

    if ((result >= TCL_OK) && (result <= TCL_CONTINUE)) {
        return resultStrings[result];
    }
    TclFormatInt(buf, result);
    return buf;
}
#endif /* TCL_COMPILE_DEBUG */

/*
 * Local Variables:
 * mode: c
 * c-basic-offset: 4
 * fill-column: 78
 * End:
 */