/*
 * 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.
 */

#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 *const operatorStrings[] = {
    "||", "&&", "|", "^", "&", "==", "!=", "<", ">", "<=", ">=", "<<", ">>",
    "+", "-", "*", "/", "%", "+", "-", "~", "!"
};

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

#ifdef TCL_COMPILE_DEBUG
static const char *const 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 {
    const 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 const 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},
    {NULL, 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)

#define STACK_BASE(esPtr) ((esPtr)->stackWords - 1)

/*
 * 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[] = {46340, 1290, 215, 73, 35, 21, 14};
static const size_t MaxBase32Size = sizeof(MaxBase32)/sizeof(long);

/*
 * 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 size_t Exp32IndexSize = sizeof(Exp32Index)/sizeof(unsigned short);
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
};
static const size_t Exp32ValueSize = sizeof(Exp32Value)/sizeof(long);

#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 const Tcl_WideInt MaxBase64[] = {
    (Tcl_WideInt)46340*65536+62259,	/* 3037000499 == isqrt(2**63-1) */
    (Tcl_WideInt)2097151, (Tcl_WideInt)55108, (Tcl_WideInt)6208,
    (Tcl_WideInt)1448, (Tcl_WideInt)511, (Tcl_WideInt)234, (Tcl_WideInt)127,
    (Tcl_WideInt)78, (Tcl_WideInt)52, (Tcl_WideInt)38, (Tcl_WideInt)28,
    (Tcl_WideInt)22, (Tcl_WideInt)18, (Tcl_WideInt)15
};
static const size_t MaxBase64Size = sizeof(MaxBase64)/sizeof(Tcl_WideInt);

/*
 *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 size_t Exp64IndexSize = sizeof(Exp64Index)/sizeof(unsigned short);
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
};
static const size_t Exp64ValueSize = sizeof(Exp64Value)/sizeof(Tcl_WideInt);

#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 searchMode,
			    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. */
{
#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 */
}

/*
 *----------------------------------------------------------------------
 *
 * 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 = STACK_BASE(esPtr);

    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.
 *
 * WALLOCALIGN represents the alignment reqs in words, just as TCL_ALLOCALIGN
 * represents the reqs in bytes. This assumes that TCL_ALLOCALIGN is a
 * multiple of the wordsize 'sizeof(Tcl_Obj *)'.
 */

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

/*
 * wordSkip computes how many words have to be skipped until the next aligned
 * word. Note that we are only interested in the low order bits of ptr, so
 * that any possible information loss in PTR2INT is of no consequence.
 */

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

/*
 * Given a marker, compute where the following aligned memory starts.
 */

#define MEMSTART(markerPtr)			\
    ((markerPtr) + wordSkip(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;
    int moveWords = 0;

    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 = wordSkip(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 one for
     * the marker, (WALLOCALIGN-1) for the maximal possible offset.
     */

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

    /*
     * 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 - STACK_BASE(esPtr);
	if (esPtr->markerPtr || (esPtr->tosPtr != STACK_BASE(esPtr))) {
	    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 - STACK_BASE(esPtr);
    }

    /*
     * 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), moveWords*sizeof(Tcl_Obj *));
	esPtr->tosPtr += moveWords;
	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) {
	ckfree((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 = STACK_BASE(esPtr);
    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 *) ckalloc(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 *) ckrealloc((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.twoPtrValue.ptr1;
	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.twoPtrValue.ptr1;
#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.twoPtrValue.ptr1;

    codePtr->refCount--;
    if (codePtr->refCount <= 0) {
	TclCleanupByteCode(codePtr);
    }
    objPtr->typePtr = 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.twoPtrValue.ptr1;
	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;
	    }
	}

	/*
	 * #280.
	 * Literal sharing fix. This part of the fix is not required by 8.4
	 * because it eval-directs any literals, so just saving the argument
	 * locations per command in bytecode is enough, embedded 'eval'
	 * commands, etc. get the correct information.
	 *
	 * It had be backported for 8.5 because we can force the separate
	 * compiling of a literal (in a proc body) by putting it into a control
	 * command with dynamic pieces, and then such literal may be shared
	 * and require their line-information to be reset, as for 8.6, as
	 * described below.
	 *
	 * In 8.6 all the embedded script are compiled, and the resulting
	 * bytecode stored in the literal. Now the shared literal has bytecode
	 * with location data for _one_ particular location this literal is
	 * found at. If we get executed from a different location the bytecode
	 * has to be recompiled to get the correct locations. Not doing this
	 * will execute the saved bytecode with data for a different location,
	 * causing 'info frame' to point to the wrong place in the sources.
	 *
	 * Future optimizations ...
	 * (1) Save the location data (ExtCmdLoc) keyed by start line. In that
	 *     case we recompile once per location of the literal, but not
	 *     continously, because the moment we have all locations we do not
	 *     need to recompile any longer.
	 *
	 * (2) Alternative: Do not recompile, tell the execution engine the
	 *     offset between saved starting line and actual one. Then modify
	 *     the users to adjust the locations they have by this offset.
	 *
	 * (3) Alternative 2: Do not fully recompile, adjust just the location
	 *     information.
	 */

	if (invoker) {
	    Tcl_HashEntry *hePtr =
		    Tcl_FindHashEntry(iPtr->lineBCPtr, (char *) codePtr);

	    if (hePtr) {
		ExtCmdLoc *eclPtr = Tcl_GetHashValue(hePtr);
		int redo = 0;
		CmdFrame *ctxPtr = TclStackAlloc(interp,sizeof(CmdFrame));

		*ctxPtr = *invoker;

		if (invoker->type == TCL_LOCATION_BC) {
		    /*
		     * Note: Type BC => ctx.data.eval.path    is not used.
		     *		    ctx.data.tebc.codePtr used instead
		     */

		    TclGetSrcInfoForPc(ctxPtr);
		    if (ctxPtr->type == TCL_LOCATION_SOURCE) {
			/*
			 * The reference made by 'TclGetSrcInfoForPc' is
			 * dead.
			 */

			Tcl_DecrRefCount(ctxPtr->data.eval.path);
			ctxPtr->data.eval.path = NULL;
		    }
		}

		if (word < ctxPtr->nline) {
		    /*
		     * Note: We do not care if the line[word] is -1. This
		     * is a difference and requires a recompile (location
		     * changed from absolute to relative, literal is used
		     * fixed and through variable)
		     *
		     * Example:
		     * test info-32.0 using literal of info-24.8
		     *     (dict with ... vs           set body ...).
		     */

		    redo = ((eclPtr->type == TCL_LOCATION_SOURCE)
			    && (eclPtr->start != ctxPtr->line[word]))
			|| ((eclPtr->type == TCL_LOCATION_BC)
				&& (ctxPtr->type == TCL_LOCATION_SOURCE));
		}

		TclStackFree(interp, ctxPtr);

		if (redo) {
		    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.twoPtrValue.ptr1;
    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
    const 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,
		(sizeof(CmdFrame) + sizeof(Tcl_Obj *) - 1)/sizeof(Tcl_Obj *) +
		codePtr->maxExceptDepth + 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", (int) 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;
		if (result == TCL_ERROR) {
		    /*
		     * Tcl_EvalEx already did the task of logging
		     * the error to the stack trace for us, so set
		     * a flag to prevent the TEBC exception handling
		     * machinery from trying to do it again.
		     * Tcl Bug 2037338.  See test execute-8.4.
		     */
		    iPtr->flags |= ERR_ALREADY_LOGGED;
		}
		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);
		appendLen >= 0 && currPtr<=&OBJ_AT_TOS; currPtr++) {
	    bytes = TclGetStringFromObj(*currPtr, &length);
	    if (bytes != NULL) {
		appendLen += length;
	    }
	}

	if (appendLen < 0) {
	    /* TODO: convert panic to error ? */
	    Tcl_Panic("max size for a Tcl value (%d bytes) exceeded", INT_MAX);
	}

	/*
	 * 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 (length + appendLen < 0) {
	    /* TODO: convert panic to error ? */
	    Tcl_Panic("max size for a Tcl value (%d bytes) exceeded", INT_MAX);
	}
#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;
	    bcFramePtr = (CmdFrame *) (initCatchTop + codePtr->maxExceptDepth + 1);
	    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;
	    if (iPtr->flags & INTERP_DEBUG_FRAME) {
		TclArgumentBCEnter((Tcl_Interp *) iPtr, objv, objc,
			codePtr, bcFramePtr, pc - codePtr->codeStart);
	    }
	    DECACHE_STACK_INFO();
	    result = TclEvalObjvInternal(interp, objc, objv,
		    /* call from TEBC */(char *) -1, -1, 0);
	    CACHE_STACK_INFO();
	    if (iPtr->flags & INTERP_DEBUG_FRAME) {
		TclArgumentBCRelease((Tcl_Interp *) iPtr, objv, objc,
			codePtr, pc - codePtr->codeStart);
	    }
	    iPtr->cmdFramePtr = iPtr->cmdFramePtr->nextPtr;

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

		/*
		 * 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;
#ifndef TCL_COMPILE_DEBUG
		if (*(pc+pcAdjustment) == INST_POP) {
		    TclDecrRefCount(objResultPtr);
		    NEXT_INST_V((pcAdjustment+1), objc, 0);
		}
#endif
		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);
	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);
	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);
	goto doStoreArray;

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

    case INST_LAPPEND_SCALAR1:
	opnd = TclGetUInt1AtPtr(pc+1);
	pcAdjustment = 2;
	storeFlags = (TCL_LEAVE_ERR_MSG | TCL_APPEND_VALUE
		| TCL_LIST_ELEMENT);
	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")));
	    DECACHE_STACK_INFO();
	    IllegalExprOperandType(interp, pc, valuePtr);
	    CACHE_STACK_INFO();
	    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")));
	    DECACHE_STACK_INFO();
	    IllegalExprOperandType(interp, pc, value2Ptr);
	    CACHE_STACK_INFO();
	    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 (TclIsPureByteArray(valuePtr)
		&& TclIsPureByteArray(value2Ptr)) {
	    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 (TclIsPureByteArray(valuePtr)) {
	    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 (TclIsPureByteArray(valuePtr)) {
		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 (TclIsPureByteArray(valuePtr) && !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")));
	    DECACHE_STACK_INFO();
	    IllegalExprOperandType(interp, pc, valuePtr);
	    CACHE_STACK_INFO();
	    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")));
	    DECACHE_STACK_INFO();
	    IllegalExprOperandType(interp, pc, value2Ptr);
	    CACHE_STACK_INFO();
	    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")));
	    DECACHE_STACK_INFO();
	    IllegalExprOperandType(interp, pc, valuePtr);
	    CACHE_STACK_INFO();
	    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")));
	    DECACHE_STACK_INFO();
	    IllegalExprOperandType(interp, pc, value2Ptr);
	    CACHE_STACK_INFO();
	    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")));
	    DECACHE_STACK_INFO();
	    IllegalExprOperandType(interp, pc, valuePtr);
	    CACHE_STACK_INFO();
	    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")));
	    DECACHE_STACK_INFO();
	    IllegalExprOperandType(interp, pc, value2Ptr);
	    CACHE_STACK_INFO();
	    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)));
		DECACHE_STACK_INFO();
		TclExprFloatError(interp, dResult);
		CACHE_STACK_INFO();
		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;
	    int oddExponent = 0, negativeExponent = 0;
#if (LONG_MAX > 0x7fffffff) || !defined(TCL_WIDE_INT_IS_LONG)
	    Tcl_WideInt w1;
#endif

	    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 (type1 == TCL_NUMBER_LONG) {
		l1 = *((const long *)ptr1);
	    }
	    if (negativeExponent) {
		if (type1 == TCL_NUMBER_LONG) {
		    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) {
		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);
		}
	    }
	    /*
	     * We refuse to accept exponent arguments that exceed
	     * one mp_digit which means the max exponent value is
	     * 2**28-1 = 0x0fffffff = 268435455, which fits into
	     * a signed 32 bit int which is within the range of the
	     * long int type.  This means any numeric Tcl_Obj value
	     * not using TCL_NUMBER_LONG type must hold a value larger
	     * than we accept.
	     */
	    if (type2 != TCL_NUMBER_LONG) {
		Tcl_SetObjResult(interp,
			Tcl_NewStringObj("exponent too large", -1));
		result = TCL_ERROR;
		goto checkForCatch;
	    }

	    if (type1 == 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
		    goto overflow;
		}
		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
		    goto overflow;
		}
#if (LONG_MAX == 0x7fffffff)
		if (l2 - 2 < (long)MaxBase32Size
			&& 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 >= 0 && l1 - 2 < (long)Exp32IndexSize
			&& l2 - 2 < (long)(Exp32ValueSize + MaxBase32Size)) {

		    unsigned short base = Exp32Index[l1 - 3]
			    + (unsigned short) (l2 - 2 - MaxBase32Size);
		    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 >= 0 && -l1 - 2 < (long)Exp32IndexSize
			&& l2 - 2 < (long)(Exp32ValueSize + MaxBase32Size)) {
		    unsigned short base = Exp32Index[-l1 - 3]
			    + (unsigned short) (l2 - 2 - MaxBase32Size);
		    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 (LONG_MAX > 0x7fffffff) || !defined(TCL_WIDE_INT_IS_LONG)
	    if (type1 == TCL_NUMBER_LONG) {
		w1 = l1;
#ifndef NO_WIDE_TYPE
	    } else if (type1 == TCL_NUMBER_WIDE) {
		w1 = *((const Tcl_WideInt*) ptr1);
#endif
	    } else {
		goto overflow;
	    }
	    if (l2 - 2 < (long)MaxBase64Size
		    && w1 <=  MaxBase64[l2 - 2]
		    && w1 >= -MaxBase64[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 >= 0 && w1 - 2 < (long)Exp64IndexSize
		    && l2 - 2 < (long)(Exp64ValueSize + MaxBase64Size)) {
		unsigned short base = Exp64Index[w1 - 3]
			+ (unsigned short) (l2 - 2 - MaxBase64Size);

		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 >= 0 && -w1 - 2 < (long)Exp64IndexSize
		    && l2 - 2 < (long)(Exp64ValueSize + MaxBase64Size)) {
		unsigned short base = Exp64Index[-w1 - 3]
			+ (unsigned short) (l2 - 2 - MaxBase64Size);

		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")));
	    DECACHE_STACK_INFO();
	    IllegalExprOperandType(interp, pc, valuePtr);
	    CACHE_STACK_INFO();
	    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")));
	    DECACHE_STACK_INFO();
	    IllegalExprOperandType(interp, pc, valuePtr);
	    CACHE_STACK_INFO();
	    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")));
	    DECACHE_STACK_INFO();
	    IllegalExprOperandType(interp, pc, valuePtr);
	    CACHE_STACK_INFO();
	    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")));
		DECACHE_STACK_INFO();
		IllegalExprOperandType(interp, pc, valuePtr);
		CACHE_STACK_INFO();
		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")));
		DECACHE_STACK_INFO();
		IllegalExprOperandType(interp, pc, valuePtr);
		CACHE_STACK_INFO();
	    } else {
		/*
		 * Numeric conversion of NaN -> error.
		 */

		TRACE(("\"%.20s\" => IEEE FLOATING PT ERROR\n",
			O2S(objResultPtr)));
		DECACHE_STACK_INFO();
		TclExprFloatError(interp, *((const double *)ptr));
		CACHE_STACK_INFO();
	    }
	    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), (int) (catchTop - initCatchTop - 1),
		(int) CURR_DEPTH));
	NEXT_INST_F(5, 0, 0);

    case INST_END_CATCH:
	catchTop--;
	DECACHE_STACK_INFO();
	Tcl_ResetResult(interp);
	CACHE_STACK_INFO();
	result = TCL_OK;
	TRACE(("=> catchTop=%d\n", (int) (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 {
	    DECACHE_STACK_INFO();
	    Tcl_ResetResult(interp);
	    Tcl_AppendResult(interp, "key \"", TclGetString(OBJ_AT_TOS),
		    "\" not known in dictionary", NULL);
	    CACHE_STACK_INFO();
	    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) {
		    TclInvalidateStringRep(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:
    DECACHE_STACK_INFO();
    Tcl_SetObjResult(interp, Tcl_NewStringObj("divide by zero", -1));
    Tcl_SetErrorCode(interp, "ARITH", "DIVZERO", "divide by zero", NULL);
    CACHE_STACK_INFO();

    result = TCL_ERROR;
    goto checkForCatch;

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

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

    if (opcode == INST_EXPON) {
	operator = "**";
    } else if (opcode <= INST_LNOT) {
	operator = operatorStrings[opcode - INST_LOR];
    }

    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));
    Tcl_SetErrorCode(interp, "ARITH", "DOMAIN", description, NULL);
}

/*
 *----------------------------------------------------------------------
 *
 * 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:
 *	If the searchMode is TCL_ERROR, this procedure ignores loop exception
 *	ranges and returns a pointer to the closest catch range. If the
 *	searchMode is TCL_BREAK, this procedure returns a pointer to the most
 *	closely enclosing ExceptionRange regardless of whether it is a loop or
 *	catch exception range. If the searchMode is TCL_CONTINUE, this
 *	procedure returns a pointer to the most closely enclosing
 *	ExceptionRange (of any type) skipping only loop exception ranges if
 *	they don't have a sensible continueOffset defined. 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 searchMode,		/* If TCL_BREAK, consider either loop or catch
				 * ExceptionRanges in search. If TCL_ERROR
				 * consider only catch ranges (and ignore any
				 * closer loop ranges). If TCL_CONTINUE, look
				 * for loop ranges that define a continue
				 * point or a catch range. */
    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 (rangePtr->type == CATCH_EXCEPTION_RANGE) {
		return rangePtr;
	    }
	    if (searchMode == TCL_BREAK) {
		return rangePtr;
	    }
	    if (searchMode == TCL_CONTINUE && rangePtr->continueOffset != -1){
		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;
    Tcl_Obj *objPtr;

#define Percent(a,b) ((a) * 100.0 / (b))

    objPtr = Tcl_NewObj();
    Tcl_IncrRefCount(objPtr);

    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.
     */

    Tcl_AppendPrintfToObj(objPtr, "\n----------------------------------------------------------------\n");
    Tcl_AppendPrintfToObj(objPtr,
	    "Compilation and execution statistics for interpreter %#lx\n",
	    iPtr);

    Tcl_AppendPrintfToObj(objPtr, "\nNumber ByteCodes executed	%ld\n",
	    statsPtr->numExecutions);
    Tcl_AppendPrintfToObj(objPtr, "Number ByteCodes compiled	%ld\n",
	    statsPtr->numCompilations);
    Tcl_AppendPrintfToObj(objPtr, "  Mean executions/compile	%.1f\n",
	    statsPtr->numExecutions / (float)statsPtr->numCompilations);

    Tcl_AppendPrintfToObj(objPtr, "\nInstructions executed		%.0f\n",
	    numInstructions);
    Tcl_AppendPrintfToObj(objPtr, "  Mean inst/compile		%.0f\n",
	    numInstructions / statsPtr->numCompilations);
    Tcl_AppendPrintfToObj(objPtr, "  Mean inst/execution		%.0f\n",
	    numInstructions / statsPtr->numExecutions);

    Tcl_AppendPrintfToObj(objPtr, "\nTotal ByteCodes			%ld\n",
	    statsPtr->numCompilations);
    Tcl_AppendPrintfToObj(objPtr, "  Source bytes			%.6g\n",
	    statsPtr->totalSrcBytes);
    Tcl_AppendPrintfToObj(objPtr, "  Code bytes			%.6g\n",
	    totalCodeBytes);
    Tcl_AppendPrintfToObj(objPtr, "    ByteCode bytes		%.6g\n",
	    statsPtr->totalByteCodeBytes);
    Tcl_AppendPrintfToObj(objPtr, "    Literal bytes		%.6g\n",
	    totalLiteralBytes);
    Tcl_AppendPrintfToObj(objPtr, "      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);
    Tcl_AppendPrintfToObj(objPtr, "  Mean code/compile		%.1f\n",
	    totalCodeBytes / statsPtr->numCompilations);
    Tcl_AppendPrintfToObj(objPtr, "  Mean code/source		%.1f\n",
	    totalCodeBytes / statsPtr->totalSrcBytes);

    Tcl_AppendPrintfToObj(objPtr, "\nCurrent (active) ByteCodes	%ld\n",
	    numCurrentByteCodes);
    Tcl_AppendPrintfToObj(objPtr, "  Source bytes			%.6g\n",
	    statsPtr->currentSrcBytes);
    Tcl_AppendPrintfToObj(objPtr, "  Code bytes			%.6g\n",
	    currentCodeBytes);
    Tcl_AppendPrintfToObj(objPtr, "    ByteCode bytes		%.6g\n",
	    statsPtr->currentByteCodeBytes);
    Tcl_AppendPrintfToObj(objPtr, "    Literal bytes		%.6g\n",
	    currentLiteralBytes);
    Tcl_AppendPrintfToObj(objPtr, "      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);
    Tcl_AppendPrintfToObj(objPtr, "  Mean code/source		%.1f\n",
	    currentCodeBytes / statsPtr->currentSrcBytes);
    Tcl_AppendPrintfToObj(objPtr, "  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;
    Tcl_AppendPrintfToObj(objPtr, "\nTcl_IsShared object check (all objects):\n");
    Tcl_AppendPrintfToObj(objPtr, "  Object had refcount <=1 (not shared)	%ld\n",
	    tclObjsShared[1]);
    for (i = 2;  i < TCL_MAX_SHARED_OBJ_STATS;  i++) {
	Tcl_AppendPrintfToObj(objPtr, "  refcount ==%d		%ld\n",
		i, tclObjsShared[i]);
	numSharedMultX += tclObjsShared[i];
    }
    Tcl_AppendPrintfToObj(objPtr, "  refcount >=%d		%ld\n",
	    i, tclObjsShared[0]);
    numSharedMultX += tclObjsShared[0];
    Tcl_AppendPrintfToObj(objPtr, "  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;

    Tcl_AppendPrintfToObj(objPtr, "\nTotal objects (all interps)	%ld\n",
	    tclObjsAlloced);
    Tcl_AppendPrintfToObj(objPtr, "Current objects			%ld\n",
	    (tclObjsAlloced - tclObjsFreed));
    Tcl_AppendPrintfToObj(objPtr, "Total literal objects		%ld\n",
	    statsPtr->numLiteralsCreated);

    Tcl_AppendPrintfToObj(objPtr, "\nCurrent literal objects		%d (%0.1f%% of current objects)\n",
	    globalTablePtr->numEntries,
	    Percent(globalTablePtr->numEntries, tclObjsAlloced-tclObjsFreed));
    Tcl_AppendPrintfToObj(objPtr, "  ByteCode literals	 	%ld (%0.1f%% of current literals)\n",
	    numByteCodeLits,
	    Percent(numByteCodeLits, globalTablePtr->numEntries));
    Tcl_AppendPrintfToObj(objPtr, "  Literals reused > 1x	 	%d\n",
	    numSharedMultX);
    Tcl_AppendPrintfToObj(objPtr, "  Mean reference count	 	%.2f\n",
	    ((double) refCountSum) / globalTablePtr->numEntries);
    Tcl_AppendPrintfToObj(objPtr, "  Mean len, str reused >1x 	%.2f\n",
	    (numSharedMultX ? strBytesSharedMultX/numSharedMultX : 0.0));
    Tcl_AppendPrintfToObj(objPtr, "  Mean len, str used 1x	 	%.2f\n",
	    (numSharedOnce ? strBytesSharedOnce/numSharedOnce : 0.0));
    Tcl_AppendPrintfToObj(objPtr, "  Total sharing savings	 	%.6g (%0.1f%% of bytes if no sharing)\n",
	    sharingBytesSaved,
	    Percent(sharingBytesSaved, objBytesIfUnshared+strBytesIfUnshared));
    Tcl_AppendPrintfToObj(objPtr, "    Bytes with sharing		%.6g\n",
	    currentLiteralBytes);
    Tcl_AppendPrintfToObj(objPtr, "      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);
    Tcl_AppendPrintfToObj(objPtr, "    Bytes if no sharing		%.6g = objects %.6g + strings %.6g\n",
	    (objBytesIfUnshared + strBytesIfUnshared),
	    objBytesIfUnshared, strBytesIfUnshared);
    Tcl_AppendPrintfToObj(objPtr, "  String sharing savings 	%.6g = unshared %.6g - shared %.6g\n",
	    (strBytesIfUnshared - statsPtr->currentLitStringBytes),
	    strBytesIfUnshared, statsPtr->currentLitStringBytes);
    Tcl_AppendPrintfToObj(objPtr, "  Literal mgmt overhead	 	%ld (%0.1f%% of bytes with sharing)\n",
	    literalMgmtBytes,
	    Percent(literalMgmtBytes, currentLiteralBytes));
    Tcl_AppendPrintfToObj(objPtr, "    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.
     */

    Tcl_AppendPrintfToObj(objPtr, "\nBreakdown of current ByteCode requirements:\n");
    Tcl_AppendPrintfToObj(objPtr, "                         Bytes      Pct of    Avg per\n");
    Tcl_AppendPrintfToObj(objPtr, "                                     total    ByteCode\n");
    Tcl_AppendPrintfToObj(objPtr, "Total             %12.6g     100.00%%   %8.1f\n",
	    statsPtr->currentByteCodeBytes,
	    statsPtr->currentByteCodeBytes / numCurrentByteCodes);
    Tcl_AppendPrintfToObj(objPtr, "Header            %12.6g   %8.1f%%   %8.1f\n",
	    currentHeaderBytes,
	    Percent(currentHeaderBytes, statsPtr->currentByteCodeBytes),
	    currentHeaderBytes / numCurrentByteCodes);
    Tcl_AppendPrintfToObj(objPtr, "Instructions      %12.6g   %8.1f%%   %8.1f\n",
	    statsPtr->currentInstBytes,
	    Percent(statsPtr->currentInstBytes,statsPtr->currentByteCodeBytes),
	    statsPtr->currentInstBytes / numCurrentByteCodes);
    Tcl_AppendPrintfToObj(objPtr, "Literal ptr array %12.6g   %8.1f%%   %8.1f\n",
	    statsPtr->currentLitBytes,
	    Percent(statsPtr->currentLitBytes,statsPtr->currentByteCodeBytes),
	    statsPtr->currentLitBytes / numCurrentByteCodes);
    Tcl_AppendPrintfToObj(objPtr, "Exception table   %12.6g   %8.1f%%   %8.1f\n",
	    statsPtr->currentExceptBytes,
	    Percent(statsPtr->currentExceptBytes,statsPtr->currentByteCodeBytes),
	    statsPtr->currentExceptBytes / numCurrentByteCodes);
    Tcl_AppendPrintfToObj(objPtr, "Auxiliary data    %12.6g   %8.1f%%   %8.1f\n",
	    statsPtr->currentAuxBytes,
	    Percent(statsPtr->currentAuxBytes,statsPtr->currentByteCodeBytes),
	    statsPtr->currentAuxBytes / numCurrentByteCodes);
    Tcl_AppendPrintfToObj(objPtr, "Command map       %12.6g   %8.1f%%   %8.1f\n",
	    statsPtr->currentCmdMapBytes,
	    Percent(statsPtr->currentCmdMapBytes,statsPtr->currentByteCodeBytes),
	    statsPtr->currentCmdMapBytes / numCurrentByteCodes);

    /*
     * Detailed literal statistics.
     */

    Tcl_AppendPrintfToObj(objPtr, "\nLiteral string sizes:\n");
    Tcl_AppendPrintfToObj(objPtr, "	 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];
	Tcl_AppendPrintfToObj(objPtr, "	%10d		%8.0f%%\n",
		decadeHigh, Percent(sum, statsPtr->numLiteralsCreated));
    }

    litTableStats = TclLiteralStats(globalTablePtr);
    Tcl_AppendPrintfToObj(objPtr, "\nCurrent literal table statistics:\n%s\n",
	    litTableStats);
    ckfree((char *) litTableStats);

    /*
     * Source and ByteCode size distributions.
     */

    Tcl_AppendPrintfToObj(objPtr, "\nSource sizes:\n");
    Tcl_AppendPrintfToObj(objPtr, "	 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];
	Tcl_AppendPrintfToObj(objPtr, "	%10d		%8.0f%%\n",
		decadeHigh, Percent(sum, statsPtr->numCompilations));
    }

    Tcl_AppendPrintfToObj(objPtr, "\nByteCode sizes:\n");
    Tcl_AppendPrintfToObj(objPtr, "	 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];
	Tcl_AppendPrintfToObj(objPtr, "	%10d		%8.0f%%\n",
		decadeHigh, Percent(sum, statsPtr->numCompilations));
    }

    Tcl_AppendPrintfToObj(objPtr, "\nByteCode longevity (excludes Current ByteCodes):\n");
    Tcl_AppendPrintfToObj(objPtr, "	       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];
	Tcl_AppendPrintfToObj(objPtr, "	%12.3f		%8.0f%%\n",
		decadeHigh/1000.0, Percent(sum, statsPtr->numByteCodesFreed));
    }

    /*
     * Instruction counts.
     */

    Tcl_AppendPrintfToObj(objPtr, "\nInstruction counts:\n");
    for (i = 0;  i <= LAST_INST_OPCODE;  i++) {
	Tcl_AppendPrintfToObj(objPtr, "%20s %8ld ",
		tclInstructionTable[i].name, statsPtr->instructionCount[i]);
	if (statsPtr->instructionCount[i]) {
	    Tcl_AppendPrintfToObj(objPtr, "%6.1f%%\n",
		    Percent(statsPtr->instructionCount[i], numInstructions));
	} else {
	    Tcl_AppendPrintfToObj(objPtr, "0\n");
	}
    }

#ifdef TCL_MEM_DEBUG
    Tcl_AppendPrintfToObj(objPtr, "\nHeap Statistics:\n");
    TclDumpMemoryInfo((ClientData) objPtr, 1);
#endif
    Tcl_AppendPrintfToObj(objPtr, "\n----------------------------------------------------------------\n");

    if (objc == 1) {
	Tcl_SetObjResult(interp, objPtr);
    } else {
	Tcl_Channel outChan;
	char *str = Tcl_GetStringFromObj(objv[1], &length);

	if (length) {
	    if (strcmp(str, "stdout") == 0) {
		outChan = Tcl_GetStdChannel(TCL_STDOUT);
	    } else if (strcmp(str, "stderr") == 0) {
		outChan = Tcl_GetStdChannel(TCL_STDERR);
	    } else {
		outChan = Tcl_OpenFileChannel(NULL, str, "w", 0664);
	    }
	} else {
	    outChan = Tcl_GetStdChannel(TCL_STDOUT);
	}
	if (outChan != NULL) {
	    Tcl_WriteObj(outChan, objPtr);
	}
    }
    Tcl_DecrRefCount(objPtr);
    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:
 */
