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tclExecute.c

/* 
 * tclExecute.c --
 *
 *    This file contains procedures that execute byte-compiled Tcl
 *    commands.
 *
 * Copyright (c) 1996-1997 Sun Microsystems, Inc.
 *
 * See the file "license.terms" for information on usage and redistribution
 * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 *
 * RCS: @(#) $Id: tclExecute.c,v 1.4 1998/09/14 18:39:58 stanton Exp $
 */

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

#ifdef NO_FLOAT_H
#   include "../compat/float.h"
#else
#   include <float.h>
#endif
#ifndef TCL_NO_MATH
#include "tclMath.h"
#endif

/*
 * The stuff below is a bit of a hack so that this file can be used
 * in environments that include no UNIX, i.e. no errno.  Just define
 * errno here.
 */

#ifndef TCL_GENERIC_ONLY
#include "tclPort.h"
#else
#define NO_ERRNO_H
#endif

#ifdef NO_ERRNO_H
int errno;
#define EDOM 33
#define ERANGE 34
#endif

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

static int execInitialized = 0;

/*
 * 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;

/*
 * The following global variable is use to signal matherr that Tcl
 * is responsible for the arithmetic, so errors can be handled in a
 * fashion appropriate for Tcl.  Zero means no Tcl math is in
 * progress;  non-zero means Tcl is doing math.
 */

int tcl_MathInProgress = 0;

/*
 * The variable below serves no useful purpose except to generate
 * a reference to matherr, so that the Tcl version of matherr is
 * linked in rather than the system version. Without this reference
 * the need for matherr won't be discovered during linking until after
 * libtcl.a has been processed, so Tcl's version won't be used.
 */

#ifdef NEED_MATHERR
extern int matherr();
int (*tclMatherrPtr)() = matherr;
#endif

/*
 * Array of instruction names.
 */

static char *opName[256];

/*
 * 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.
 */

static char *operatorStrings[] = {
    "||", "&&", "|", "^", "&", "==", "!=", "<", ">", "<=", ">=", "<<", ">>",
    "+", "-", "*", "/", "%", "+", "-", "~", "!",
    "BUILTIN FUNCTION", "FUNCTION"
};
    
/*
 * Mapping from Tcl result codes to strings; used for error and debugging
 * messages. 
 */

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

/*
 * The following are statistics-related variables that record information
 * about the bytecode compiler and interpreter's operation. This includes
 * an array that records for each instruction how often it is executed.
 */

#ifdef TCL_COMPILE_STATS
static long numExecutions = 0;
static int instructionCount[256];
#endif /* TCL_COMPILE_STATS */

/*
 * Macros for testing floating-point values for certain special cases. Test
 * for not-a-number by comparing a value against itself; test for infinity
 * by comparing against the largest floating-point value.
 */

#define IS_NAN(v) ((v) != (v))
#ifdef DBL_MAX
#   define IS_INF(v) (((v) > DBL_MAX) || ((v) < -DBL_MAX))
#else
#   define IS_INF(v) 0
#endif

/*
 * Macro to adjust the program counter and restart the instruction execution
 * loop after each instruction is executed.
 */

#define ADJUST_PC(instBytes) \
    pc += instBytes;  continue

/*
 * 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() \
    stackPtr = eePtr->stackPtr; \
    stackTop = eePtr->stackTop

#define DECACHE_STACK_INFO() \
    eePtr->stackTop = stackTop

/*
 * 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.
 */

#define STK_ITEM(offset)    (stackPtr[stackTop + (offset)])
#define STK_OBJECT(offset)  (STK_ITEM(offset).o)
#define STK_INT(offset)     (STK_ITEM(offset).i)
#define STK_POINTER(offset) (STK_ITEM(offset).p)

/*
 * 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(stackPtr[++stackTop].o = (objPtr))
    
#define POP_OBJECT() \
    (stackPtr[stackTop--].o)

/*
 * 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.
 * 
 * NOTE THAT CLIENTS OF O2S ARE LIKELY TO FAIL IF THE OBJECT'S
 * STRING REP CONTAINS NULLS. 
 */

#ifdef TCL_COMPILE_DEBUG
      
#define O2S(objPtr) \
    Tcl_GetStringFromObj((objPtr), &length)
      
#ifdef TCL_COMPILE_STATS
#define TRACE(a) \
    if (traceInstructions) { \
        fprintf(stdout, "%d: %d,%ld (%u) ", iPtr->numLevels, \
             stackTop, (tclObjsAlloced - tclObjsFreed), \
             (unsigned int)(pc - codePtr->codeStart)); \
      printf a; \
        fflush(stdout); \
    }
#define TRACE_WITH_OBJ(a, objPtr) \
    if (traceInstructions) { \
        fprintf(stdout, "%d: %d,%ld (%u) ", iPtr->numLevels, \
             stackTop, (tclObjsAlloced - tclObjsFreed), \
             (unsigned int)(pc - codePtr->codeStart)); \
      printf a; \
      bytes = Tcl_GetStringFromObj((objPtr), &length); \
        TclPrintSource(stdout, bytes, TclMin(length, 30)); \
        fprintf(stdout, "\n"); \
        fflush(stdout); \
    }
#else  /* not TCL_COMPILE_STATS */
#define TRACE(a) \
    if (traceInstructions) { \
        fprintf(stdout, "%d: %d (%u) ", iPtr->numLevels, stackTop, \
             (unsigned int)(pc - codePtr->codeStart)); \
      printf a; \
        fflush(stdout); \
    }
#define TRACE_WITH_OBJ(a, objPtr) \
    if (traceInstructions) { \
        fprintf(stdout, "%d: %d (%u) ", iPtr->numLevels, stackTop, \
             (unsigned int)(pc - codePtr->codeStart)); \
      printf a; \
      bytes = Tcl_GetStringFromObj((objPtr), &length); \
        TclPrintSource(stdout, bytes, TclMin(length, 30)); \
        fprintf(stdout, "\n"); \
        fflush(stdout); \
    }
#endif /* TCL_COMPILE_STATS */

#else  /* not TCL_COMPILE_DEBUG */
      
#define TRACE(a)
#define TRACE_WITH_OBJ(a, objPtr)
#define O2S(objPtr)
      
#endif /* TCL_COMPILE_DEBUG */

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

static void       CallTraceProcedure _ANSI_ARGS_((Tcl_Interp *interp,
                      Trace *tracePtr, Command *cmdPtr,
                      char *command, int numChars,
                      int objc, Tcl_Obj *objv[]));
static void       DupCmdNameInternalRep _ANSI_ARGS_((Tcl_Obj *objPtr,
                      Tcl_Obj *copyPtr));
static int        ExprAbsFunc _ANSI_ARGS_((Tcl_Interp *interp,
                      ExecEnv *eePtr, ClientData clientData));
static int        ExprBinaryFunc _ANSI_ARGS_((Tcl_Interp *interp,
                      ExecEnv *eePtr, ClientData clientData));
static int        ExprCallMathFunc _ANSI_ARGS_((Tcl_Interp *interp,
                      ExecEnv *eePtr, int objc, Tcl_Obj **objv));
static int        ExprDoubleFunc _ANSI_ARGS_((Tcl_Interp *interp,
                      ExecEnv *eePtr, ClientData clientData));
static int        ExprIntFunc _ANSI_ARGS_((Tcl_Interp *interp,
                      ExecEnv *eePtr, ClientData clientData));
static int        ExprRandFunc _ANSI_ARGS_((Tcl_Interp *interp,
                      ExecEnv *eePtr, ClientData clientData));
static int        ExprRoundFunc _ANSI_ARGS_((Tcl_Interp *interp,
                      ExecEnv *eePtr, ClientData clientData));
static int        ExprSrandFunc _ANSI_ARGS_((Tcl_Interp *interp,
                      ExecEnv *eePtr, ClientData clientData));
static int        ExprUnaryFunc _ANSI_ARGS_((Tcl_Interp *interp,
                      ExecEnv *eePtr, ClientData clientData));
#ifdef TCL_COMPILE_STATS
static int              EvalStatsCmd _ANSI_ARGS_((ClientData clientData,
                            Tcl_Interp *interp, int argc, char **argv));
#endif /* TCL_COMPILE_STATS */
static void       FreeCmdNameInternalRep _ANSI_ARGS_((
                      Tcl_Obj *objPtr));
static char *           GetSrcInfoForPc _ANSI_ARGS_((unsigned char *pc,
                      ByteCode* codePtr, int *lengthPtr));
static void       GrowEvaluationStack _ANSI_ARGS_((ExecEnv *eePtr));
static void       IllegalExprOperandType _ANSI_ARGS_((
                      Tcl_Interp *interp, unsigned int opCode,
                      Tcl_Obj *opndPtr));
static void       InitByteCodeExecution _ANSI_ARGS_((
                      Tcl_Interp *interp));
static void       PrintByteCodeInfo _ANSI_ARGS_((ByteCode *codePtr));
static void       RecordTracebackInfo _ANSI_ARGS_((Tcl_Interp *interp,
                      unsigned char *pc, ByteCode *codePtr));
static int        SetCmdNameFromAny _ANSI_ARGS_((Tcl_Interp *interp,
                      Tcl_Obj *objPtr));
#ifdef TCL_COMPILE_DEBUG
static char *           StringForResultCode _ANSI_ARGS_((int result));
#endif /* TCL_COMPILE_DEBUG */
static void       UpdateStringOfCmdName _ANSI_ARGS_((Tcl_Obj *objPtr));
#ifdef TCL_COMPILE_DEBUG
static void       ValidatePcAndStackTop _ANSI_ARGS_((
                      ByteCode *codePtr, unsigned char *pc,
                      int stackTop, int stackLowerBound,
                      int stackUpperBound));
#endif /* TCL_COMPILE_DEBUG */

/*
 * 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.
 */

BuiltinFunc builtinFuncTable[] = {
#ifndef TCL_NO_MATH
    {"acos", 1, {TCL_DOUBLE}, ExprUnaryFunc, (ClientData) acos},
    {"asin", 1, {TCL_DOUBLE}, ExprUnaryFunc, (ClientData) asin},
    {"atan", 1, {TCL_DOUBLE}, ExprUnaryFunc, (ClientData) atan},
    {"atan2", 2, {TCL_DOUBLE, TCL_DOUBLE}, ExprBinaryFunc, (ClientData) atan2},
    {"ceil", 1, {TCL_DOUBLE}, ExprUnaryFunc, (ClientData) ceil},
    {"cos", 1, {TCL_DOUBLE}, ExprUnaryFunc, (ClientData) cos},
    {"cosh", 1, {TCL_DOUBLE}, ExprUnaryFunc, (ClientData) cosh},
    {"exp", 1, {TCL_DOUBLE}, ExprUnaryFunc, (ClientData) exp},
    {"floor", 1, {TCL_DOUBLE}, ExprUnaryFunc, (ClientData) floor},
    {"fmod", 2, {TCL_DOUBLE, TCL_DOUBLE}, ExprBinaryFunc, (ClientData) fmod},
    {"hypot", 2, {TCL_DOUBLE, TCL_DOUBLE}, ExprBinaryFunc, (ClientData) hypot},
    {"log", 1, {TCL_DOUBLE}, ExprUnaryFunc, (ClientData) log},
    {"log10", 1, {TCL_DOUBLE}, ExprUnaryFunc, (ClientData) log10},
    {"pow", 2, {TCL_DOUBLE, TCL_DOUBLE}, ExprBinaryFunc, (ClientData) pow},
    {"sin", 1, {TCL_DOUBLE}, ExprUnaryFunc, (ClientData) sin},
    {"sinh", 1, {TCL_DOUBLE}, ExprUnaryFunc, (ClientData) sinh},
    {"sqrt", 1, {TCL_DOUBLE}, ExprUnaryFunc, (ClientData) sqrt},
    {"tan", 1, {TCL_DOUBLE}, ExprUnaryFunc, (ClientData) tan},
    {"tanh", 1, {TCL_DOUBLE}, ExprUnaryFunc, (ClientData) tanh},
#endif
    {"abs", 1, {TCL_EITHER}, ExprAbsFunc, 0},
    {"double", 1, {TCL_EITHER}, ExprDoubleFunc, 0},
    {"int", 1, {TCL_EITHER}, ExprIntFunc, 0},
    {"rand", 0, {TCL_EITHER}, ExprRandFunc, 0}, /* NOTE: rand takes no args. */
    {"round", 1, {TCL_EITHER}, ExprRoundFunc, 0},
    {"srand", 1, {TCL_INT}, ExprSrandFunc, 0},
    {0},
};

/*
 * The structure below defines the command name Tcl object type by means of
 * procedures that can be invoked by generic object code. Objects of this
 * type cache the Command pointer that results from looking up command names
 * in the command hashtable. Such objects appear as the zeroth ("command
 * name") argument in a Tcl command.
 */

Tcl_ObjType tclCmdNameType = {
    "cmdName",                      /* name */
    FreeCmdNameInternalRep,         /* freeIntRepProc */
    DupCmdNameInternalRep,          /* dupIntRepProc */
    UpdateStringOfCmdName,          /* updateStringProc */
    SetCmdNameFromAny               /* 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 registers the command name
 *    Tcl_ObjType. It also establishes the link between the Tcl
 *    "tcl_traceExec" and C "tclTraceExec" variables.
 *
 *----------------------------------------------------------------------
 */

static void
InitByteCodeExecution(interp)
    Tcl_Interp *interp;       /* Interpreter for which the Tcl variable
                         * "tcl_traceExec" is linked to control
                         * instruction tracing. */
{
    int i;
    
    Tcl_RegisterObjType(&tclCmdNameType);

    (VOID *) memset(opName, 0, sizeof(opName));
    for (i = 0;  instructionTable[i].name != NULL;  i++) {
      opName[i] = instructionTable[i].name;
    }

#ifdef TCL_COMPILE_STATS    
    (VOID *) memset(instructionCount, 0, sizeof(instructionCount));
    (VOID *) memset(tclByteCodeCount, 0, sizeof(tclByteCodeCount));
    (VOID *) memset(tclSourceCount, 0, sizeof(tclSourceCount));

    Tcl_CreateCommand(interp, "evalstats", EvalStatsCmd,
                  (ClientData) NULL, (Tcl_CmdDeleteProc *) NULL);
#endif /* TCL_COMPILE_STATS */
    
    if (Tcl_LinkVar(interp, "tcl_traceExec", (char *) &tclTraceExec,
                TCL_LINK_INT) != TCL_OK) {
      panic("InitByteCodeExecution: can't create link for tcl_traceExec variable");
    }
}

/*
 *----------------------------------------------------------------------
 *
 * 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(interp)
    Tcl_Interp *interp;       /* Interpreter for which the execution
                         * environment is being created. */
{
    ExecEnv *eePtr = (ExecEnv *) ckalloc(sizeof(ExecEnv));

    eePtr->stackPtr = (StackItem *)
      ckalloc((unsigned) (TCL_STACK_INITIAL_SIZE * sizeof(StackItem)));
    eePtr->stackTop = -1;
    eePtr->stackEnd = (TCL_STACK_INITIAL_SIZE - 1);

    if (!execInitialized) {
        TclInitAuxDataTypeTable();
        InitByteCodeExecution(interp);
        execInitialized = 1;
    }

    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.
 *
 *----------------------------------------------------------------------
 */

void
TclDeleteExecEnv(eePtr)
    ExecEnv *eePtr;           /* Execution environment to free. */
{
    ckfree((char *) eePtr->stackPtr);
    ckfree((char *) eePtr);
}

/*
 *----------------------------------------------------------------------
 *
 * TclFinalizeExecEnv --
 *
 *    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
TclFinalizeExecEnv()
{
    execInitialized = 0;
    TclFinalizeAuxDataTypeTable();
}

/*
 *----------------------------------------------------------------------
 *
 * GrowEvaluationStack --
 *
 *    This procedure grows a Tcl evaluation stack stored in an ExecEnv.
 *
 * Results:
 *    None.
 *
 * Side effects:
 *    The size of the evaluation stack is doubled.
 *
 *----------------------------------------------------------------------
 */

static void
GrowEvaluationStack(eePtr)
    register ExecEnv *eePtr; /* Points to the ExecEnv with an evaluation
                        * stack to enlarge. */
{
    /*
     * The current Tcl stack elements are stored from eePtr->stackPtr[0]
     * to eePtr->stackPtr[eePtr->stackEnd] (inclusive).
     */

    int currElems = (eePtr->stackEnd + 1);
    int newElems  = 2*currElems;
    int currBytes = currElems * sizeof(StackItem);
    int newBytes  = 2*currBytes;
    StackItem *newStackPtr = (StackItem *) ckalloc((unsigned) newBytes);

    /*
     * Copy the existing stack items to the new stack space, free the old
     * storage if appropriate, and mark new space as malloc'ed.
     */
 
    memcpy((VOID *) newStackPtr, (VOID *) eePtr->stackPtr,
         (size_t) currBytes);
    ckfree((char *) eePtr->stackPtr);
    eePtr->stackPtr = newStackPtr;
    eePtr->stackEnd = (newElems - 1); /* i.e. index of last usable item */
}

/*
 *----------------------------------------------------------------------
 *
 * 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(interp, codePtr)
    Tcl_Interp *interp;       /* Token for command interpreter. */
    ByteCode *codePtr;        /* The bytecode sequence to interpret. */
{
    Interp *iPtr = (Interp *) interp;
    ExecEnv *eePtr = iPtr->execEnvPtr;
                        /* Points to the execution environment. */
    register StackItem *stackPtr = eePtr->stackPtr;
                        /* Cached evaluation stack base pointer. */
    register int stackTop = eePtr->stackTop;
                        /* Cached top index of evaluation stack. */
    Tcl_Obj **objArrayPtr = codePtr->objArrayPtr;
                        /* Points to the ByteCode's object array. */
    unsigned char *pc = codePtr->codeStart;
                        /* The current program counter. */
    unsigned char opCode;     /* The current instruction code. */
    int opnd;                 /* Current instruction's operand byte. */
    int pcAdjustment;         /* Hold pc adjustment after instruction. */
    int initStackTop = stackTop;/* Stack top at start of execution. */
    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. */
    int result = TCL_OK;      /* Return code returned after execution. */
    int traceInstructions = (tclTraceExec == 3);
    Tcl_Obj *valuePtr, *value2Ptr, *namePtr, *objPtr;
    char *bytes;
    int length;
    long i;
    Tcl_DString command;      /* Used for debugging. If tclTraceExec >= 2
                         * holds a string representing the last
                         * command invoked. */

    /*
     * This procedure uses a stack to hold information about catch commands.
     * This information is the current operand stack top when starting to
     * execute the code for each catch command. It starts out with stack-
     * allocated space but uses dynamically-allocated storage if needed.
     */

#define STATIC_CATCH_STACK_SIZE 5
    int (catchStackStorage[STATIC_CATCH_STACK_SIZE]);
    int *catchStackPtr = catchStackStorage;
    int catchTop = -1;

    /*
     * THIS PROC FAILS IF AN OBJECT'S STRING REP HAS A NULL BYTE.
     */

    if (tclTraceExec >= 2) {
      PrintByteCodeInfo(codePtr);
#ifdef TCL_COMPILE_STATS
      fprintf(stdout, "  Starting stack top=%d, system objects=%ld\n",
            eePtr->stackTop, (tclObjsAlloced - tclObjsFreed));
#else
      fprintf(stdout, "  Starting stack top=%d\n", eePtr->stackTop);
#endif /* TCL_COMPILE_STATS */
      fflush(stdout);
    }

#ifdef TCL_COMPILE_STATS
    numExecutions++;
#endif /* TCL_COMPILE_STATS */

    /*
     * 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.
     */

    if (codePtr->maxExcRangeDepth > STATIC_CATCH_STACK_SIZE) {
      catchStackPtr = (int *)
              ckalloc(codePtr->maxExcRangeDepth * sizeof(int));
    }

    /*
     * Make sure the stack has enough room to execute this ByteCode.
     */

    while ((stackTop + codePtr->maxStackDepth) > eePtr->stackEnd) {
        GrowEvaluationStack(eePtr); 
        stackPtr = eePtr->stackPtr;
    }

    /*
     * Initialize the buffer that holds a string containing the name and
     * arguments for the last invoked command.
     */

    Tcl_DStringInit(&command);

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

    for (;;) {
#ifdef TCL_COMPILE_DEBUG
      ValidatePcAndStackTop(codePtr, pc, stackTop, initStackTop,
            eePtr->stackEnd);
#else /* not TCL_COMPILE_DEBUG */
      if (traceInstructions) {
#ifdef TCL_COMPILE_STATS
          fprintf(stdout, "%d: %d,%ld ", iPtr->numLevels, stackTop,
                (tclObjsAlloced - tclObjsFreed));
#else /* TCL_COMPILE_STATS */
          fprintf(stdout, "%d: %d ", iPtr->numLevels, stackTop);
#endif /* TCL_COMPILE_STATS */
          TclPrintInstruction(codePtr, pc);
          fflush(stdout);
      }
#endif /* TCL_COMPILE_DEBUG */
      
      opCode = *pc;
#ifdef TCL_COMPILE_STATS    
      instructionCount[opCode]++;
#endif /* TCL_COMPILE_STATS */

        switch (opCode) {
      case INST_DONE:
          /*
           * Pop the topmost object from the stack, set the interpreter's
           * object result to point to it, and return.
           */
          valuePtr = POP_OBJECT();
          Tcl_SetObjResult(interp, valuePtr);
          TclDecrRefCount(valuePtr);
          if (stackTop != initStackTop) {
            fprintf(stderr, "\nTclExecuteByteCode: done instruction at pc %u: stack top %d != entry stack top %d\n",
                  (unsigned int)(pc - codePtr->codeStart),
                  (unsigned int) stackTop,
                  (unsigned int) initStackTop);
            fprintf(stderr, "  Source: ");
            TclPrintSource(stderr, codePtr->source, 150);
            panic("TclExecuteByteCode execution failure: end stack top != start stack top");
          }
          TRACE_WITH_OBJ(("done => return code=%d, result is ", result),
                iPtr->objResultPtr);
          goto done;
          
      case INST_PUSH1:
          valuePtr = objArrayPtr[TclGetUInt1AtPtr(pc+1)];
          PUSH_OBJECT(valuePtr);
          TRACE_WITH_OBJ(("push1 %u => ", TclGetUInt1AtPtr(pc+1)),
                  valuePtr);
          ADJUST_PC(2);
          
      case INST_PUSH4:
          valuePtr = objArrayPtr[TclGetUInt4AtPtr(pc+1)];
          PUSH_OBJECT(valuePtr);
          TRACE_WITH_OBJ(("push4 %u => ", TclGetUInt4AtPtr(pc+1)),
                valuePtr);
          ADJUST_PC(5);
          
      case INST_POP:
          valuePtr = POP_OBJECT();
          TRACE_WITH_OBJ(("pop => discarding "), valuePtr);
          TclDecrRefCount(valuePtr); /* finished with pop'ed object. */
          ADJUST_PC(1);

      case INST_DUP:
          valuePtr = stackPtr[stackTop].o;
          PUSH_OBJECT(Tcl_DuplicateObj(valuePtr));
          TRACE_WITH_OBJ(("dup => "), valuePtr);
          ADJUST_PC(1);

      case INST_CONCAT1:
          opnd = TclGetUInt1AtPtr(pc+1);
          {
            Tcl_Obj *concatObjPtr;
            int totalLen = 0;

            /*
             * Concatenate strings (with no separators) from the top
             * opnd items on the stack starting with the deepest item.
             * First, determine how many characters are needed.
             */

            for (i = (stackTop - (opnd-1));  i <= stackTop;  i++) {
                valuePtr = stackPtr[i].o;
                bytes = TclGetStringFromObj(valuePtr, &length);
                if (bytes != NULL) {
                  totalLen += length;
                }
                }

            /*
             * Initialize the new append string object by appending the
             * strings of the opnd stack objects. Also pop the objects. 
             */

            TclNewObj(concatObjPtr);
            if (totalLen > 0) {
                char *p = (char *) ckalloc((unsigned) (totalLen + 1));
                concatObjPtr->bytes = p;
                concatObjPtr->length = totalLen;
                for (i = (stackTop - (opnd-1));  i <= stackTop;  i++) {
                  valuePtr = stackPtr[i].o;
                  bytes = TclGetStringFromObj(valuePtr, &length);
                  if (bytes != NULL) {
                      memcpy((VOID *) p, (VOID *) bytes,
                              (size_t) length);
                      p += length;
                  }
                  TclDecrRefCount(valuePtr);
                }
                *p = '\0';
            } else {
                for (i = (stackTop - (opnd-1));  i <= stackTop;  i++) {
                  valuePtr = stackPtr[i].o;
                  Tcl_DecrRefCount(valuePtr);
                }
            }
            stackTop -= opnd;
            
            PUSH_OBJECT(concatObjPtr);
            TRACE_WITH_OBJ(("concat %u => ", opnd), concatObjPtr);
            ADJUST_PC(2);
            }
          
      case INST_INVOKE_STK4:
          opnd = TclGetUInt4AtPtr(pc+1);
          pcAdjustment = 5;
          goto doInvocation;

      case INST_INVOKE_STK1:
          opnd = TclGetUInt1AtPtr(pc+1);
          pcAdjustment = 2;
          
          doInvocation:
          {
            char *cmdName;
            Command *cmdPtr;   /* Points to command's Command struct. */
            int objc = opnd;   /* The number of arguments. */
            Tcl_Obj **objv;      /* The array of argument objects. */
            Tcl_Obj *objv0Ptr; /* Holds objv[0], the command name. */
            int newPcOffset = 0;
                           /* Instruction offset computed during
                            * break, continue, error processing.
                            * Init. to avoid compiler warning. */
            Tcl_Command cmd;
#ifdef TCL_COMPILE_DEBUG
            int isUnknownCmd = 0;
            char cmdNameBuf[30];
#endif /* TCL_COMPILE_DEBUG */
            
            /*
             * If the interpreter was deleted, return an error.
             */
            
            if (iPtr->flags & DELETED) {
                Tcl_ResetResult(interp);
                Tcl_AppendToObj(Tcl_GetObjResult(interp),
                        "attempt to call eval in deleted interpreter", -1);
                Tcl_SetErrorCode(interp, "CORE", "IDELETE",
                      "attempt to call eval in deleted interpreter",
                      (char *) NULL);
                result = TCL_ERROR;
                goto checkForCatch;
            }
    
            objv = &(stackPtr[stackTop - (objc-1)].o);
            objv0Ptr = objv[0];
            cmdName = TclGetStringFromObj(objv0Ptr, (int *) NULL);
            
            /*
             * Find the procedure to execute this command. If there
             * isn't one, then see if there is a command "unknown". If
             * so, invoke it, passing it the original command words as
             * arguments.
             *
             * We convert the objv[0] object to be a CmdName object.
             * This caches a pointer to the Command structure for the
             * command; this pointer is held in a ResolvedCmdName
             * structure the object's internal rep. points to.
             */

            cmd = Tcl_GetCommandFromObj(interp, objv0Ptr);
            cmdPtr = (Command *) cmd;
            
            /*
             * If the command is still not found, handle it with the
             * "unknown" proc.
             */

            if (cmdPtr == NULL) {
                cmd = Tcl_FindCommand(interp, "unknown",
                            (Tcl_Namespace *) NULL, /*flags*/ TCL_GLOBAL_ONLY);
                    if (cmd == (Tcl_Command) NULL) {
                  Tcl_ResetResult(interp);
                  Tcl_AppendStringsToObj(Tcl_GetObjResult(interp),
                          "invalid command name \"", cmdName, "\"",
                        (char *) NULL);
                  TRACE(("%s %u => unknown proc not found: ",
                         opName[opCode], objc));
                  result = TCL_ERROR;
                  goto checkForCatch;
                }
                cmdPtr = (Command *) cmd;
#ifdef TCL_COMPILE_DEBUG
                isUnknownCmd = 1;
#endif /*TCL_COMPILE_DEBUG*/              
                stackTop++; /* need room for new inserted objv[0] */
                for (i = objc;  i >= 0;  i--) {
                  objv[i+1] = objv[i];
                }
                objc++;
                objv[0] = Tcl_NewStringObj("unknown", -1);
                Tcl_IncrRefCount(objv[0]);
            }
            
            /*
             * Call any trace procedures.
             */

            if (iPtr->tracePtr != NULL) {
                Trace *tracePtr, *nextTracePtr;

                for (tracePtr = iPtr->tracePtr;  tracePtr != NULL;
                        tracePtr = nextTracePtr) {
                  nextTracePtr = tracePtr->nextPtr;
                  if (iPtr->numLevels <= tracePtr->level) {
                      int numChars;
                      char *cmd = GetSrcInfoForPc(pc, codePtr,
                            &numChars);
                      if (cmd != NULL) {
                        DECACHE_STACK_INFO();
                        CallTraceProcedure(interp, tracePtr, cmdPtr,
                                cmd, numChars, objc, objv);
                        CACHE_STACK_INFO();
                      }
                  }
                }
            }
            
            /*
             * Finally, invoke the command's Tcl_ObjCmdProc. First reset
             * the interpreter's string and object results to their
             * default empty values since they could have gotten changed
             * by earlier invocations.
             */
            
            Tcl_ResetResult(interp);

            if (tclTraceExec >= 2) {
                char buffer[50];

                sprintf(buffer, "%d: (%u) invoking ", iPtr->numLevels,
                      (unsigned int)(pc - codePtr->codeStart));
                Tcl_DStringAppend(&command, buffer, -1);
                
#ifdef TCL_COMPILE_DEBUG
                if (traceInstructions) { /* tclTraceExec == 3 */
                  strncpy(cmdNameBuf, cmdName, 20);
                  TRACE(("%s %u => call ", opName[opCode],
                         (isUnknownCmd? objc-1 : objc)));
                } else {
                  fprintf(stdout, "%s", buffer);
                }
#else /* TCL_COMPILE_DEBUG */
                fprintf(stdout, "%s", buffer);
#endif /*TCL_COMPILE_DEBUG*/

                for (i = 0;  i < objc;  i++) {
                  bytes = TclGetStringFromObj(objv[i], &length);
                  TclPrintSource(stdout, bytes, TclMin(length, 15));
                  fprintf(stdout, " ");

                  sprintf(buffer, "\"%.*s\" ", TclMin(length, 15), bytes);
                  Tcl_DStringAppend(&command, buffer, -1);
                }
                fprintf(stdout, "\n");
                fflush(stdout);

                Tcl_DStringFree(&command);
            }

            iPtr->cmdCount++;
            DECACHE_STACK_INFO();
            result = (*cmdPtr->objProc)(cmdPtr->objClientData, interp,
                                  objc, objv);
            if (Tcl_AsyncReady()) {
                result = Tcl_AsyncInvoke(interp, result);
            }
            CACHE_STACK_INFO();

            /*
             * If the interpreter has a non-empty string result, the
             * result object is either empty or stale because some
             * procedure set interp->result directly. If so, move the
             * string result to the result object, then reset the
             * string result.
             */

            if (*(iPtr->result) != 0) {
                (void) Tcl_GetObjResult(interp);
            }
            
            /*
             * Pop the objc top stack elements and decrement their ref
             * counts. 
             */
            
            i = (stackTop - (objc-1));
            while (i <= stackTop) {
                valuePtr = stackPtr[i].o;
                TclDecrRefCount(valuePtr);
                i++;
            }
            stackTop -= objc;

            /*
             * Process the result of the Tcl_ObjCmdProc call.
             */
            
            switch (result) {
            case TCL_OK:
                /*
                 * Push the call's object result and continue execution
                 * with the next instruction.
                 */
                PUSH_OBJECT(Tcl_GetObjResult(interp));
                TRACE_WITH_OBJ(("%s %u => ...after \"%.20s\", result=",
                        opName[opCode], objc, cmdNameBuf),
                      Tcl_GetObjResult(interp));
                ADJUST_PC(pcAdjustment);
                
            case TCL_BREAK:
            case TCL_CONTINUE:
                /*
                 * The invoked command requested a break or continue.
                 * Find the closest enclosing loop or catch exception
                 * range, if any. If a loop is found, terminate its
                 * execution or skip to its next iteration. If the
                 * closest is a catch exception range, jump to its
                 * catchOffset. If no enclosing range is found, stop
                 * execution and return the TCL_BREAK or TCL_CONTINUE.
                 */
                rangePtr = TclGetExceptionRangeForPc(pc,
                            /*catchOnly*/ 0, codePtr);
                if (rangePtr == NULL) {
                    TRACE(("%s %u => ... after \"%.20s\", no encl. loop or catch, returning %s\n",
                            opName[opCode], objc, cmdNameBuf,
                          StringForResultCode(result)));
                  goto abnormalReturn; /* no catch exists to check */
                }
                switch (rangePtr->type) {
                case LOOP_EXCEPTION_RANGE:
                  if (result == TCL_BREAK) {
                      newPcOffset = rangePtr->breakOffset;
                  } else if (rangePtr->continueOffset == -1) {
                      TRACE(("%s %u => ... after \"%.20s\", %s, loop w/o continue, checking for catch\n",
                           opName[opCode], objc, cmdNameBuf,
                           StringForResultCode(result)));
                      goto checkForCatch;
                  } else {
                      newPcOffset = rangePtr->continueOffset;
                  }
                  TRACE(("%s %u => ... after \"%.20s\", %s, range at %d, new pc %d\n",
                         opName[opCode], objc, cmdNameBuf,
                         StringForResultCode(result),
                         rangePtr->codeOffset, newPcOffset));
                  break;
                case CATCH_EXCEPTION_RANGE:
                  TRACE(("%s %u => ... after \"%.20s\", %s...\n",
                         opName[opCode], objc, cmdNameBuf,
                         StringForResultCode(result)));
                  goto processCatch; /* it will use rangePtr */
                default:
                  panic("TclExecuteByteCode: unrecognized ExceptionRange type %d\n", rangePtr->type);
                }
                result = TCL_OK;
                pc = (codePtr->codeStart + newPcOffset);
                continue;     /* restart outer instruction loop at pc */
                
            case TCL_ERROR:
                /*
                 * The invoked command returned an error. Look for an
                 * enclosing catch exception range, if any.
                 */
                TRACE_WITH_OBJ(("%s %u => ... after \"%.20s\", TCL_ERROR ",
                        opName[opCode], objc, cmdNameBuf),
                      Tcl_GetObjResult(interp));
                goto checkForCatch;

            case TCL_RETURN:
                /*
                 * The invoked command requested that the current
                 * procedure stop execution and return. First check
                 * for an enclosing catch exception range, if any.
                 */
                TRACE(("%s %u => ... after \"%.20s\", TCL_RETURN\n",
                        opName[opCode], objc, cmdNameBuf));
                goto checkForCatch;

            default:
                TRACE_WITH_OBJ(("%s %u => ... after \"%.20s\", OTHER RETURN CODE %d ",
                        opName[opCode], objc, cmdNameBuf, result),
                      Tcl_GetObjResult(interp));
                goto checkForCatch;
            } /* end of switch on result from invoke instruction */
          }
          
      case INST_EVAL_STK:
          objPtr = POP_OBJECT();
          DECACHE_STACK_INFO();
          result = Tcl_EvalObj(interp, objPtr);
          CACHE_STACK_INFO();
          if (result == TCL_OK) {
            /*
             * Normal return; push the eval's object result.
             */
            
            PUSH_OBJECT(Tcl_GetObjResult(interp));
            TRACE_WITH_OBJ(("evalStk \"%.30s\" => ", O2S(objPtr)),
                  Tcl_GetObjResult(interp));
            TclDecrRefCount(objPtr);
            ADJUST_PC(1);
          } else if ((result == TCL_BREAK) || (result == TCL_CONTINUE)) {
            /*
             * Find the closest enclosing loop or catch exception range,
             * if any. If a loop is found, terminate its execution or
             * skip to its next iteration. If the closest is a catch
             * exception range, jump to its catchOffset. If no enclosing
             * range is found, stop execution and return that same
             * TCL_BREAK or TCL_CONTINUE.
             */

            int newPcOffset = 0; /* Pc offset computed during break,
                              * continue, error processing. Init.
                              * to avoid compiler warning. */

            rangePtr = TclGetExceptionRangeForPc(pc, /*catchOnly*/ 0,
                  codePtr);
            if (rangePtr == NULL) {
                TRACE(("evalStk \"%.30s\" => no encl. loop or catch, returning %s\n",
                      O2S(objPtr), StringForResultCode(result)));
                Tcl_DecrRefCount(objPtr);
                goto abnormalReturn;    /* no catch exists to check */
            }
            switch (rangePtr->type) {
            case LOOP_EXCEPTION_RANGE:
                if (result == TCL_BREAK) {
                  newPcOffset = rangePtr->breakOffset;
                } else if (rangePtr->continueOffset == -1) {
                  TRACE(("evalStk \"%.30s\" => %s, loop w/o continue, checking for catch\n",
                         O2S(objPtr), StringForResultCode(result)));
                  Tcl_DecrRefCount(objPtr);
                  goto checkForCatch;
                } else {
                  newPcOffset = rangePtr->continueOffset;
                }
                result = TCL_OK;
                TRACE_WITH_OBJ(("evalStk \"%.30s\" => %s, range at %d, new pc %d ",
                      O2S(objPtr), StringForResultCode(result),
                      rangePtr->codeOffset, newPcOffset), valuePtr);
                break;
            case CATCH_EXCEPTION_RANGE:
                TRACE_WITH_OBJ(("evalStk \"%.30s\" => %s ",
                      O2S(objPtr), StringForResultCode(result)),
                      valuePtr);
                Tcl_DecrRefCount(objPtr);
                goto processCatch;  /* it will use rangePtr */
            default:
                panic("TclExecuteByteCode: unrecognized ExceptionRange type %d\n", rangePtr->type);
            }
            Tcl_DecrRefCount(objPtr);
            pc = (codePtr->codeStart + newPcOffset);
            continue;   /* restart outer instruction loop at pc */
          } else { /* eval returned TCL_ERROR, TCL_RETURN, unknown code */
            TRACE_WITH_OBJ(("evalStk \"%.30s\" => ERROR: ", O2S(objPtr)),
                    Tcl_GetObjResult(interp));
            Tcl_DecrRefCount(objPtr);
            goto checkForCatch;
          }

      case INST_EXPR_STK:
          objPtr = POP_OBJECT();
          Tcl_ResetResult(interp);
          DECACHE_STACK_INFO();
          result = Tcl_ExprObj(interp, objPtr, &valuePtr);
          CACHE_STACK_INFO();
          if (result != TCL_OK) {
            TRACE_WITH_OBJ(("exprStk \"%.30s\" => ERROR: ", 
                    O2S(objPtr)), Tcl_GetObjResult(interp));
            Tcl_DecrRefCount(objPtr);
            goto checkForCatch;
          }
          stackPtr[++stackTop].o = valuePtr; /* already has right refct */
          TRACE_WITH_OBJ(("exprStk \"%.30s\" => ", O2S(objPtr)), valuePtr);
          TclDecrRefCount(objPtr);
          ADJUST_PC(1);

      case INST_LOAD_SCALAR4:
          opnd = TclGetInt4AtPtr(pc+1);
          pcAdjustment = 5;
          goto doLoadScalar;

      case INST_LOAD_SCALAR1:
          opnd = TclGetUInt1AtPtr(pc+1);
          pcAdjustment = 2;
          
          doLoadScalar:
          DECACHE_STACK_INFO();
          valuePtr = TclGetIndexedScalar(interp, opnd,
                                 /*leaveErrorMsg*/ 1);
          CACHE_STACK_INFO();
          if (valuePtr == NULL) {
            TRACE_WITH_OBJ(("%s %u => ERROR: ", opName[opCode], opnd),
                  Tcl_GetObjResult(interp));
            result = TCL_ERROR;
            goto checkForCatch;
            }
          PUSH_OBJECT(valuePtr);
          TRACE_WITH_OBJ(("%s %u => ", opName[opCode], opnd), valuePtr);
          ADJUST_PC(pcAdjustment);

      case INST_LOAD_SCALAR_STK:
          namePtr = POP_OBJECT();
          DECACHE_STACK_INFO();
          valuePtr = Tcl_ObjGetVar2(interp, namePtr, (Tcl_Obj *) NULL, 
                              TCL_LEAVE_ERR_MSG);
          CACHE_STACK_INFO();
          if (valuePtr == NULL) {
            TRACE_WITH_OBJ(("loadScalarStk \"%.30s\" => ERROR: ",
                    O2S(namePtr)), Tcl_GetObjResult(interp));
            Tcl_DecrRefCount(namePtr);
            result = TCL_ERROR;
            goto checkForCatch;
            }
          PUSH_OBJECT(valuePtr);
          TRACE_WITH_OBJ(("loadScalarStk \"%.30s\" => ",
                O2S(namePtr)), valuePtr);
          TclDecrRefCount(namePtr);
          ADJUST_PC(1);

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

      case INST_LOAD_ARRAY1:
          opnd = TclGetUInt1AtPtr(pc+1);
          pcAdjustment = 2;
          
          doLoadArray:
          {
            Tcl_Obj *elemPtr = POP_OBJECT();
            
            DECACHE_STACK_INFO();
            valuePtr = TclGetElementOfIndexedArray(interp, opnd,
                      elemPtr, /*leaveErrorMsg*/ 1);
            CACHE_STACK_INFO();
            if (valuePtr == NULL) {
                TRACE_WITH_OBJ(("%s %u \"%.30s\" => ERROR: ",
                      opName[opCode], opnd, O2S(elemPtr)),
                      Tcl_GetObjResult(interp));
                Tcl_DecrRefCount(elemPtr);
                result = TCL_ERROR;
                goto checkForCatch;
            }
            PUSH_OBJECT(valuePtr);
            TRACE_WITH_OBJ(("%s %u \"%.30s\" => ",
                    opName[opCode], opnd, O2S(elemPtr)), valuePtr);
            TclDecrRefCount(elemPtr);
          }
          ADJUST_PC(pcAdjustment);

      case INST_LOAD_ARRAY_STK:
          {
            Tcl_Obj *elemPtr = POP_OBJECT();
            
            namePtr = POP_OBJECT();
            DECACHE_STACK_INFO();
            valuePtr = Tcl_ObjGetVar2(interp, namePtr, elemPtr,
                    TCL_LEAVE_ERR_MSG);
            CACHE_STACK_INFO();
            if (valuePtr == NULL) {
                TRACE_WITH_OBJ(("loadArrayStk \"%.30s(%.30s)\" => ERROR: ",
                        O2S(namePtr), O2S(elemPtr)),
                      Tcl_GetObjResult(interp));
                Tcl_DecrRefCount(namePtr);
                Tcl_DecrRefCount(elemPtr);
                result = TCL_ERROR;
                goto checkForCatch;
            }
            PUSH_OBJECT(valuePtr);
            TRACE_WITH_OBJ(("loadArrayStk \"%.30s(%.30s)\" => ",
                    O2S(namePtr), O2S(elemPtr)), valuePtr);
            TclDecrRefCount(namePtr);
            TclDecrRefCount(elemPtr);
          }
          ADJUST_PC(1);

      case INST_LOAD_STK:
          namePtr = POP_OBJECT();
          DECACHE_STACK_INFO();
          valuePtr = Tcl_ObjGetVar2(interp, namePtr, NULL,
                TCL_PARSE_PART1|TCL_LEAVE_ERR_MSG);
          CACHE_STACK_INFO();
          if (valuePtr == NULL) {
            TRACE_WITH_OBJ(("loadStk \"%.30s\" => ERROR: ",
                    O2S(namePtr)), Tcl_GetObjResult(interp));
            Tcl_DecrRefCount(namePtr);
            result = TCL_ERROR;
            goto checkForCatch;
          }
          PUSH_OBJECT(valuePtr);
          TRACE_WITH_OBJ(("loadStk \"%.30s\" => ", O2S(namePtr)),
                valuePtr);
          TclDecrRefCount(namePtr);
          ADJUST_PC(1);
          
      case INST_STORE_SCALAR4:
          opnd = TclGetUInt4AtPtr(pc+1);
          pcAdjustment = 5;
          goto doStoreScalar;

      case INST_STORE_SCALAR1:
          opnd = TclGetUInt1AtPtr(pc+1);
          pcAdjustment = 2;
          
        doStoreScalar:
          valuePtr = POP_OBJECT();
          DECACHE_STACK_INFO();
          value2Ptr = TclSetIndexedScalar(interp, opnd, valuePtr,
                                    /*leaveErrorMsg*/ 1);
          CACHE_STACK_INFO();
          if (value2Ptr == NULL) {
            TRACE_WITH_OBJ(("%s %u <- \"%.30s\" => ERROR: ",
                  opName[opCode], opnd, O2S(valuePtr)),
                  Tcl_GetObjResult(interp));
            Tcl_DecrRefCount(valuePtr);
            result = TCL_ERROR;
            goto checkForCatch;
          }
          PUSH_OBJECT(value2Ptr);
          TRACE_WITH_OBJ(("%s %u <- \"%.30s\" => ",
                opName[opCode], opnd, O2S(valuePtr)), value2Ptr);
          TclDecrRefCount(valuePtr);
          ADJUST_PC(pcAdjustment);

      case INST_STORE_SCALAR_STK:
          valuePtr = POP_OBJECT();
          namePtr = POP_OBJECT();
          DECACHE_STACK_INFO();
          value2Ptr = Tcl_ObjSetVar2(interp, namePtr, NULL, valuePtr,
                  TCL_LEAVE_ERR_MSG);
          CACHE_STACK_INFO();
          if (value2Ptr == NULL) {
            TRACE_WITH_OBJ(
                  ("storeScalarStk \"%.30s\" <- \"%.30s\" => ERROR: ",
                    O2S(namePtr), O2S(valuePtr)),
                  Tcl_GetObjResult(interp));
            Tcl_DecrRefCount(namePtr);
            Tcl_DecrRefCount(valuePtr);
            result = TCL_ERROR;
            goto checkForCatch;
          }
          PUSH_OBJECT(value2Ptr);
          TRACE_WITH_OBJ(
                ("storeScalarStk \"%.30s\" <- \"%.30s\" => ",
                O2S(namePtr),
                O2S(valuePtr)),
                value2Ptr);
          TclDecrRefCount(namePtr);
          TclDecrRefCount(valuePtr);
          ADJUST_PC(1);

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

      case INST_STORE_ARRAY1:
          opnd = TclGetUInt1AtPtr(pc+1);
          pcAdjustment = 2;
          
          doStoreArray:
          {
            Tcl_Obj *elemPtr;

            valuePtr = POP_OBJECT();
            elemPtr = POP_OBJECT();
            DECACHE_STACK_INFO();
            value2Ptr = TclSetElementOfIndexedArray(interp, opnd,
                    elemPtr, valuePtr, TCL_LEAVE_ERR_MSG);
            CACHE_STACK_INFO();
            if (value2Ptr == NULL) {
                TRACE_WITH_OBJ(
                      ("%s %u \"%.30s\" <- \"%.30s\" => ERROR: ",
                      opName[opCode], opnd, O2S(elemPtr),
                      O2S(valuePtr)), Tcl_GetObjResult(interp));
                Tcl_DecrRefCount(elemPtr);
                Tcl_DecrRefCount(valuePtr);
                result = TCL_ERROR;
                goto checkForCatch;
            }
            PUSH_OBJECT(value2Ptr);
            TRACE_WITH_OBJ(("%s %u \"%.30s\" <- \"%.30s\" => ",
                    opName[opCode], opnd, O2S(elemPtr), O2S(valuePtr)),
                    value2Ptr);
            TclDecrRefCount(elemPtr);
            TclDecrRefCount(valuePtr);
          }
          ADJUST_PC(pcAdjustment);

      case INST_STORE_ARRAY_STK:
          {
            Tcl_Obj *elemPtr;

            valuePtr = POP_OBJECT();
            elemPtr = POP_OBJECT();
            namePtr = POP_OBJECT();
            DECACHE_STACK_INFO();
            value2Ptr = Tcl_ObjSetVar2(interp, namePtr, elemPtr,
                    valuePtr, TCL_LEAVE_ERR_MSG);
            CACHE_STACK_INFO();
            if (value2Ptr == NULL) {
                TRACE_WITH_OBJ(("storeArrayStk \"%.30s(%.30s)\" <- \"%.30s\" => ERROR: ",
                        O2S(namePtr), O2S(elemPtr), O2S(valuePtr)),
                      Tcl_GetObjResult(interp));
                Tcl_DecrRefCount(namePtr);
                Tcl_DecrRefCount(elemPtr);
                Tcl_DecrRefCount(valuePtr);
                result = TCL_ERROR;
                goto checkForCatch;
            }
            PUSH_OBJECT(value2Ptr);
            TRACE_WITH_OBJ(("storeArrayStk \"%.30s(%.30s)\" <- \"%.30s\" => ",
                    O2S(namePtr), O2S(elemPtr), O2S(valuePtr)),
                  value2Ptr);
            TclDecrRefCount(namePtr);
            TclDecrRefCount(elemPtr);
            TclDecrRefCount(valuePtr);
          }
          ADJUST_PC(1);

      case INST_STORE_STK:
          valuePtr = POP_OBJECT();
          namePtr = POP_OBJECT();
          DECACHE_STACK_INFO();
          value2Ptr = Tcl_ObjSetVar2(interp, namePtr, NULL, valuePtr,
                TCL_PARSE_PART1|TCL_LEAVE_ERR_MSG);
          CACHE_STACK_INFO();
          if (value2Ptr == NULL) {
            TRACE_WITH_OBJ(("storeStk \"%.30s\" <- \"%.30s\" => ERROR: ",
                    O2S(namePtr), O2S(valuePtr)),
                  Tcl_GetObjResult(interp));
            Tcl_DecrRefCount(namePtr);
            Tcl_DecrRefCount(valuePtr);
            result = TCL_ERROR;
            goto checkForCatch;
          }
          PUSH_OBJECT(value2Ptr);
          TRACE_WITH_OBJ(("storeStk \"%.30s\" <- \"%.30s\" => ",
                O2S(namePtr), O2S(valuePtr)), value2Ptr);
          TclDecrRefCount(namePtr);
          TclDecrRefCount(valuePtr);
          ADJUST_PC(1);

      case INST_INCR_SCALAR1:
          opnd = TclGetUInt1AtPtr(pc+1);
          valuePtr = POP_OBJECT(); 
          if (valuePtr->typePtr != &tclIntType) {
            result = tclIntType.setFromAnyProc(interp, valuePtr);
            if (result != TCL_OK) {
                TRACE_WITH_OBJ(("incrScalar1 %u (by %s) => ERROR converting increment amount to int: ",
                        opnd, O2S(valuePtr)), Tcl_GetObjResult(interp));
                Tcl_DecrRefCount(valuePtr);
                goto checkForCatch;
            }
          }
          i = valuePtr->internalRep.longValue;
          DECACHE_STACK_INFO();
          value2Ptr = TclIncrIndexedScalar(interp, opnd, i);
          CACHE_STACK_INFO();
          if (value2Ptr == NULL) {
            TRACE_WITH_OBJ(("incrScalar1 %u (by %ld) => ERROR: ",
                    opnd, i), Tcl_GetObjResult(interp));
            Tcl_DecrRefCount(valuePtr);
            result = TCL_ERROR;
            goto checkForCatch;
          }
          PUSH_OBJECT(value2Ptr);
          TRACE_WITH_OBJ(("incrScalar1 %u (by %ld) => ", opnd, i),
                value2Ptr);
          TclDecrRefCount(valuePtr);
          ADJUST_PC(2);

      case INST_INCR_SCALAR_STK:
      case INST_INCR_STK:
          valuePtr = POP_OBJECT();
          namePtr = POP_OBJECT();
          if (valuePtr->typePtr != &tclIntType) {
            result = tclIntType.setFromAnyProc(interp, valuePtr);
            if (result != TCL_OK) {
                TRACE_WITH_OBJ(("%s \"%.30s\" (by %s) => ERROR converting increment amount to int: ",
                        opName[opCode], O2S(namePtr), O2S(valuePtr)),
                      Tcl_GetObjResult(interp));
                Tcl_DecrRefCount(namePtr);
                Tcl_DecrRefCount(valuePtr);
                goto checkForCatch;
            }
          }
          i = valuePtr->internalRep.longValue;
          DECACHE_STACK_INFO();
          value2Ptr = TclIncrVar2(interp, namePtr, (Tcl_Obj *) NULL, i,
              /*part1NotParsed*/ (opCode == INST_INCR_STK));
          CACHE_STACK_INFO();
          if (value2Ptr == NULL) {
            TRACE_WITH_OBJ(("%s \"%.30s\" (by %ld) => ERROR: ",
                    opName[opCode], O2S(namePtr), i),
                  Tcl_GetObjResult(interp));
            Tcl_DecrRefCount(namePtr);
            Tcl_DecrRefCount(valuePtr);
            result = TCL_ERROR;
            goto checkForCatch;
          }
          PUSH_OBJECT(value2Ptr);
          TRACE_WITH_OBJ(("%s \"%.30s\" (by %ld) => ",
                  opName[opCode], O2S(namePtr), i), value2Ptr);
          Tcl_DecrRefCount(namePtr);
          Tcl_DecrRefCount(valuePtr);
          ADJUST_PC(1);

      case INST_INCR_ARRAY1:
          {
            Tcl_Obj *elemPtr;

            opnd = TclGetUInt1AtPtr(pc+1);
            valuePtr = POP_OBJECT();
            elemPtr = POP_OBJECT();
            if (valuePtr->typePtr != &tclIntType) {
                result = tclIntType.setFromAnyProc(interp, valuePtr);
                if (result != TCL_OK) {
                  TRACE_WITH_OBJ(("incrArray1 %u \"%.30s\" (by %s) => ERROR converting increment amount to int: ",
                            opnd, O2S(elemPtr), O2S(valuePtr)),
                          Tcl_GetObjResult(interp));
                  Tcl_DecrRefCount(elemPtr);
                  Tcl_DecrRefCount(valuePtr);
                  goto checkForCatch;
                }
            }
            i = valuePtr->internalRep.longValue;
            DECACHE_STACK_INFO();
            value2Ptr = TclIncrElementOfIndexedArray(interp, opnd,
                    elemPtr, i);
            CACHE_STACK_INFO();
            if (value2Ptr == NULL) {
                TRACE_WITH_OBJ(("incrArray1 %u \"%.30s\" (by %ld) => ERROR: ",
                        opnd, O2S(elemPtr), i),
                      Tcl_GetObjResult(interp));
                Tcl_DecrRefCount(elemPtr);
                Tcl_DecrRefCount(valuePtr);
                result = TCL_ERROR;
                goto checkForCatch;
            }
            PUSH_OBJECT(value2Ptr);
            TRACE_WITH_OBJ(("incrArray1 %u \"%.30s\" (by %ld) => ",
                      opnd, O2S(elemPtr), i), value2Ptr);
            Tcl_DecrRefCount(elemPtr);
            Tcl_DecrRefCount(valuePtr);
          }
          ADJUST_PC(2);
          
      case INST_INCR_ARRAY_STK:
          {
            Tcl_Obj *elemPtr;

            valuePtr = POP_OBJECT();
            elemPtr = POP_OBJECT();
            namePtr = POP_OBJECT();
            if (valuePtr->typePtr != &tclIntType) {
                result = tclIntType.setFromAnyProc(interp, valuePtr);
                if (result != TCL_OK) {
                    TRACE_WITH_OBJ(("incrArrayStk \"%.30s(%.30s)\" (by %s) => ERROR converting increment amount to int: ",
                            O2S(namePtr), O2S(elemPtr), O2S(valuePtr)),
                          Tcl_GetObjResult(interp));
                  Tcl_DecrRefCount(namePtr);
                  Tcl_DecrRefCount(elemPtr);
                  Tcl_DecrRefCount(valuePtr);
                  goto checkForCatch;
                }
            }
            i = valuePtr->internalRep.longValue;
            DECACHE_STACK_INFO();
            value2Ptr = TclIncrVar2(interp, namePtr, elemPtr, i,
                              /*part1NotParsed*/ 0);
            CACHE_STACK_INFO();
            if (value2Ptr == NULL) {
                TRACE_WITH_OBJ(("incrArrayStk \"%.30s(%.30s)\" (by %ld) => ERROR: ",
                        O2S(namePtr), O2S(elemPtr), i),
                      Tcl_GetObjResult(interp));
                Tcl_DecrRefCount(namePtr);
                Tcl_DecrRefCount(elemPtr);
                Tcl_DecrRefCount(valuePtr);
                result = TCL_ERROR;
                goto checkForCatch;
            }
            PUSH_OBJECT(value2Ptr);
            TRACE_WITH_OBJ(("incrArrayStk \"%.30s(%.30s)\" (by %ld) => ",
                      O2S(namePtr), O2S(elemPtr), i), value2Ptr);
            Tcl_DecrRefCount(namePtr);
            Tcl_DecrRefCount(elemPtr);
            Tcl_DecrRefCount(valuePtr);
          }
          ADJUST_PC(1);
          
      case INST_INCR_SCALAR1_IMM:
          opnd = TclGetUInt1AtPtr(pc+1);
          i = TclGetInt1AtPtr(pc+2);
          DECACHE_STACK_INFO();
          value2Ptr = TclIncrIndexedScalar(interp, opnd, i);
          CACHE_STACK_INFO();
          if (value2Ptr == NULL) {
            TRACE_WITH_OBJ(("incrScalar1Imm %u %ld => ERROR: ",
                    opnd, i), Tcl_GetObjResult(interp));
            result = TCL_ERROR;
            goto checkForCatch;
          }
          PUSH_OBJECT(value2Ptr);
          TRACE_WITH_OBJ(("incrScalar1Imm %u %ld => ", opnd, i),
                value2Ptr);
          ADJUST_PC(3);

      case INST_INCR_SCALAR_STK_IMM:
      case INST_INCR_STK_IMM:
          namePtr = POP_OBJECT();
          i = TclGetInt1AtPtr(pc+1);
          DECACHE_STACK_INFO();
          value2Ptr = TclIncrVar2(interp, namePtr, (Tcl_Obj *) NULL, i,
                /*part1NotParsed*/ (opCode == INST_INCR_STK_IMM));
          CACHE_STACK_INFO();
          if (value2Ptr == NULL) {
            TRACE_WITH_OBJ(("%s \"%.30s\" %ld => ERROR: ",
                    opName[opCode], O2S(namePtr), i),
                  Tcl_GetObjResult(interp));
            result = TCL_ERROR;
            Tcl_DecrRefCount(namePtr);
            goto checkForCatch;
          }
          PUSH_OBJECT(value2Ptr);
          TRACE_WITH_OBJ(("%s \"%.30s\" %ld => ",
                  opName[opCode], O2S(namePtr), i), value2Ptr);
          TclDecrRefCount(namePtr);
          ADJUST_PC(2);

      case INST_INCR_ARRAY1_IMM:
          {
            Tcl_Obj *elemPtr;

            opnd = TclGetUInt1AtPtr(pc+1);
            i = TclGetInt1AtPtr(pc+2);
            elemPtr = POP_OBJECT();
            DECACHE_STACK_INFO();
            value2Ptr = TclIncrElementOfIndexedArray(interp, opnd,
                    elemPtr, i);
            CACHE_STACK_INFO();
            if (value2Ptr == NULL) {
                TRACE_WITH_OBJ(("incrArray1Imm %u \"%.30s\" (by %ld) => ERROR: ",
                        opnd, O2S(elemPtr), i),
                      Tcl_GetObjResult(interp));
                Tcl_DecrRefCount(elemPtr);
                result = TCL_ERROR;
                goto checkForCatch;
            }
            PUSH_OBJECT(value2Ptr);
            TRACE_WITH_OBJ(("incrArray1Imm %u \"%.30s\" (by %ld) => ",
                      opnd, O2S(elemPtr), i), value2Ptr);
            Tcl_DecrRefCount(elemPtr);
          }
          ADJUST_PC(3);
          
      case INST_INCR_ARRAY_STK_IMM:
          {
            Tcl_Obj *elemPtr;

            i = TclGetInt1AtPtr(pc+1);
            elemPtr = POP_OBJECT();
            namePtr = POP_OBJECT();
            DECACHE_STACK_INFO();
            value2Ptr = TclIncrVar2(interp, namePtr, elemPtr, i,
                    /*part1NotParsed*/ 0);
            CACHE_STACK_INFO();
            if (value2Ptr == NULL) {
                TRACE_WITH_OBJ(("incrArrayStkImm \"%.30s(%.30s)\" (by %ld) => ERROR: ",
                        O2S(namePtr), O2S(elemPtr), i),
                      Tcl_GetObjResult(interp));
                Tcl_DecrRefCount(namePtr);
                Tcl_DecrRefCount(elemPtr);
                result = TCL_ERROR;
                goto checkForCatch;
            }
            PUSH_OBJECT(value2Ptr);
            TRACE_WITH_OBJ(("incrArrayStkImm \"%.30s(%.30s)\" (by %ld) => ",
                      O2S(namePtr), O2S(elemPtr), i), value2Ptr);
            Tcl_DecrRefCount(namePtr);
            Tcl_DecrRefCount(elemPtr);
          }
          ADJUST_PC(2);

      case INST_JUMP1:
          opnd = TclGetInt1AtPtr(pc+1);
          TRACE(("jump1 %d => new pc %u\n", opnd,
               (unsigned int)(pc + opnd - codePtr->codeStart)));
          ADJUST_PC(opnd);

      case INST_JUMP4:
          opnd = TclGetInt4AtPtr(pc+1);
          TRACE(("jump4 %d => new pc %u\n", opnd,
               (unsigned int)(pc + opnd - codePtr->codeStart)));
          ADJUST_PC(opnd);

      case INST_JUMP_TRUE4:
          opnd = TclGetInt4AtPtr(pc+1);
          pcAdjustment = 5;
          goto doJumpTrue;

      case INST_JUMP_TRUE1:
          opnd = TclGetInt1AtPtr(pc+1);
          pcAdjustment = 2;
          
          doJumpTrue:
          {
            int b;
            
            valuePtr = POP_OBJECT();
            if (valuePtr->typePtr == &tclIntType) {
                b = (valuePtr->internalRep.longValue != 0);
            } else if (valuePtr->typePtr == &tclDoubleType) {
                b = (valuePtr->internalRep.doubleValue != 0.0);
            } else {
                result = Tcl_GetBooleanFromObj(interp, valuePtr, &b);
                if (result != TCL_OK) {
                  TRACE_WITH_OBJ(("%s %d => ERROR: ", opName[opCode],
                        opnd), Tcl_GetObjResult(interp));
                  Tcl_DecrRefCount(valuePtr);
                  goto checkForCatch;
                }
            }
            if (b) {
                TRACE(("%s %d => %.20s true, new pc %u\n",
                      opName[opCode], opnd, O2S(valuePtr),
                        (unsigned int)(pc+opnd - codePtr->codeStart)));
                TclDecrRefCount(valuePtr);
                ADJUST_PC(opnd);
            } else {
                TRACE(("%s %d => %.20s false\n", opName[opCode], opnd,
                        O2S(valuePtr)));
                TclDecrRefCount(valuePtr);
                ADJUST_PC(pcAdjustment);
            }
          }
          
      case INST_JUMP_FALSE4:
          opnd = TclGetInt4AtPtr(pc+1);
          pcAdjustment = 5;
          goto doJumpFalse;

      case INST_JUMP_FALSE1:
          opnd = TclGetInt1AtPtr(pc+1);
          pcAdjustment = 2;
          
          doJumpFalse:
          {
            int b;
            
            valuePtr = POP_OBJECT();
            if (valuePtr->typePtr == &tclIntType) {
                b = (valuePtr->internalRep.longValue != 0);
            } else if (valuePtr->typePtr == &tclDoubleType) {
                b = (valuePtr->internalRep.doubleValue != 0.0);
            } else {
                result = Tcl_GetBooleanFromObj(interp, valuePtr, &b);
                if (result != TCL_OK) {
                  TRACE_WITH_OBJ(("%s %d => ERROR: ", opName[opCode],
                        opnd), Tcl_GetObjResult(interp));
                  Tcl_DecrRefCount(valuePtr);
                  goto checkForCatch;
                }
            }
            if (b) {
                TRACE(("%s %d => %.20s true\n", opName[opCode], opnd,
                        O2S(valuePtr)));
                TclDecrRefCount(valuePtr);
                ADJUST_PC(pcAdjustment);
            } else {
                TRACE(("%s %d => %.20s false, new pc %u\n",
                      opName[opCode], opnd, O2S(valuePtr),
                     (unsigned int)(pc + opnd - codePtr->codeStart)));
                TclDecrRefCount(valuePtr);
                ADJUST_PC(opnd);
            }
          }
          
      case INST_LOR:
      case INST_LAND:
          {
            /*
             * Operands must be boolean or numeric. No int->double
             * conversions are performed.
             */
            
            int i1, i2;
            int iResult;
            char *s;
            Tcl_ObjType *t1Ptr, *t2Ptr;
            
            value2Ptr = POP_OBJECT();
            valuePtr  = POP_OBJECT();
            t1Ptr = valuePtr->typePtr;
            t2Ptr = value2Ptr->typePtr;
            
            if ((t1Ptr == &tclIntType) || (t1Ptr == &tclBooleanType)) {
                i1 = (valuePtr->internalRep.longValue != 0);
            } else if (t1Ptr == &tclDoubleType) {
                i1 = (valuePtr->internalRep.doubleValue != 0.0);
            } else {    /* FAILS IF NULL STRING REP */
                s = Tcl_GetStringFromObj(valuePtr, (int *) NULL);
                if (TclLooksLikeInt(s)) {
                  result = Tcl_GetLongFromObj((Tcl_Interp *) NULL,
                        valuePtr, &i);
                  i1 = (i != 0);
                } else {
                  result = Tcl_GetBooleanFromObj((Tcl_Interp *) NULL,
                        valuePtr, &i1);
                  i1 = (i1 != 0);
                }
                if (result != TCL_OK) {
                  TRACE(("%s \"%.20s\" => ILLEGAL TYPE %s \n",
                          opName[opCode], O2S(valuePtr),
                          (t1Ptr? t1Ptr->name : "null")));
                  IllegalExprOperandType(interp, opCode, valuePtr);
                  Tcl_DecrRefCount(valuePtr);
                  Tcl_DecrRefCount(value2Ptr);
                  goto checkForCatch;
                }
            }
            
            if ((t2Ptr == &tclIntType) || (t2Ptr == &tclBooleanType)) {
                i2 = (value2Ptr->internalRep.longValue != 0);
            } else if (t2Ptr == &tclDoubleType) {
                i2 = (value2Ptr->internalRep.doubleValue != 0.0);
            } else {    /* FAILS IF NULL STRING REP */
                s = Tcl_GetStringFromObj(value2Ptr, (int *) NULL);
                if (TclLooksLikeInt(s)) {
                  result = Tcl_GetLongFromObj((Tcl_Interp *) NULL,
                        value2Ptr, &i);
                  i2 = (i != 0);
                } else {
                  result = Tcl_GetBooleanFromObj((Tcl_Interp *) NULL,
                        value2Ptr, &i2);
                  i2 = (i2 != 0);
                }
                if (result != TCL_OK) {
                  TRACE(("%s \"%.20s\" => ILLEGAL TYPE %s \n",
                          opName[opCode], O2S(value2Ptr),
                          (t2Ptr? t2Ptr->name : "null")));
                  IllegalExprOperandType(interp, opCode, value2Ptr);
                  Tcl_DecrRefCount(valuePtr);
                  Tcl_DecrRefCount(value2Ptr);
                  goto checkForCatch;
                }
            }
            
            /*
             * Reuse the valuePtr object already on stack if possible.
             */

            if (opCode == INST_LOR) {
                iResult = (i1 || i2);
            } else {
                iResult = (i1 && i2);
            }
            if (Tcl_IsShared(valuePtr)) {
                PUSH_OBJECT(Tcl_NewLongObj(iResult));
                TRACE(("%s %.20s %.20s => %d\n", opName[opCode],
                     O2S(valuePtr), O2S(value2Ptr), iResult));
                TclDecrRefCount(valuePtr);
            } else {    /* reuse the valuePtr object */
                TRACE(("%s %.20s %.20s => %d\n", 
                     opName[opCode], /* NB: stack top is off by 1 */
                     O2S(valuePtr), O2S(value2Ptr), iResult));
                Tcl_SetLongObj(valuePtr, iResult);
                ++stackTop; /* valuePtr now on stk top has right r.c. */
            }
            TclDecrRefCount(value2Ptr);
          }
          ADJUST_PC(1);

      case INST_EQ:
      case INST_NEQ:
      case INST_LT:
      case INST_GT:
      case INST_LE:
      case INST_GE:
          {
            /*
             * Any type is allowed but the two operands must have the
               * same type. We will compute value op value2.
             */

            Tcl_ObjType *t1Ptr, *t2Ptr;
            char *s1 = NULL;   /* Init. avoids compiler warning. */
            char *s2 = NULL;   /* Init. avoids compiler warning. */
            long i2 = 0;         /* Init. avoids compiler warning. */
            double d1 = 0.0;   /* Init. avoids compiler warning. */
            double d2 = 0.0;   /* Init. avoids compiler warning. */
            long iResult = 0;  /* Init. avoids compiler warning. */

            value2Ptr = POP_OBJECT();
            valuePtr  = POP_OBJECT();
            t1Ptr = valuePtr->typePtr;
            t2Ptr = value2Ptr->typePtr;
            
            if ((t1Ptr != &tclIntType) && (t1Ptr != &tclDoubleType)) {
                s1 = Tcl_GetStringFromObj(valuePtr, &length);
                if (TclLooksLikeInt(s1)) { /* FAILS IF NULLS */
                  (void) Tcl_GetLongFromObj((Tcl_Interp *) NULL,
                        valuePtr, &i);
                } else {
                  (void) Tcl_GetDoubleFromObj((Tcl_Interp *) NULL,
                        valuePtr, &d1);
                }
                t1Ptr = valuePtr->typePtr;
            }
            if ((t2Ptr != &tclIntType) && (t2Ptr != &tclDoubleType)) {
                s2 = Tcl_GetStringFromObj(value2Ptr, &length);
                if (TclLooksLikeInt(s2)) { /* FAILS IF NULLS */
                  (void) Tcl_GetLongFromObj((Tcl_Interp *) NULL,
                        value2Ptr, &i2);
                } else {
                  (void) Tcl_GetDoubleFromObj((Tcl_Interp *) NULL,
                        value2Ptr, &d2);
                }
                t2Ptr = value2Ptr->typePtr;
            }

            if (((t1Ptr != &tclIntType) && (t1Ptr != &tclDoubleType))
                    || ((t2Ptr != &tclIntType) && (t2Ptr != &tclDoubleType))) {
                /*
                 * One operand is not numeric. Compare as strings.
                 * THIS FAILS IF AN OBJECT'S STRING REP CONTAINS NULLS.
                 */
                int cmpValue;
                s1 = TclGetStringFromObj(valuePtr, &length);
                s2 = TclGetStringFromObj(value2Ptr, &length);
                cmpValue = strcmp(s1, s2);
                switch (opCode) {
                case INST_EQ:
                  iResult = (cmpValue == 0);
                  break;
                case INST_NEQ:
                  iResult = (cmpValue != 0);
                  break;
                case INST_LT:
                  iResult = (cmpValue < 0);
                  break;
                case INST_GT:
                  iResult = (cmpValue > 0);
                  break;
                case INST_LE:
                  iResult = (cmpValue <= 0);
                  break;
                case INST_GE:
                  iResult = (cmpValue >= 0);
                  break;
                }
            } else if ((t1Ptr == &tclDoubleType)
                    || (t2Ptr == &tclDoubleType)) {
                /*
                 * Compare as doubles.
                 */
                if (t1Ptr == &tclDoubleType) {
                  d1 = valuePtr->internalRep.doubleValue;
                  if (t2Ptr == &tclIntType) {
                      d2 = value2Ptr->internalRep.longValue;
                  } else {
                      d2 = value2Ptr->internalRep.doubleValue;
                  }
                } else {      /* t1Ptr is int, t2Ptr is double */
                  d1 = valuePtr->internalRep.longValue;
                  d2 = value2Ptr->internalRep.doubleValue;
                }
                switch (opCode) {
                case INST_EQ:
                  iResult = d1 == d2;
                  break;
                case INST_NEQ:
                  iResult = d1 != d2;
                  break;
                case INST_LT:
                  iResult = d1 < d2;
                  break;
                case INST_GT:
                  iResult = d1 > d2;
                  break;
                case INST_LE:
                  iResult = d1 <= d2;
                  break;
                case INST_GE:
                  iResult = d1 >= d2;
                  break;
                }
            } else {
                /*
                 * Compare as ints.
                 */
                i  = valuePtr->internalRep.longValue;
                i2 = value2Ptr->internalRep.longValue;
                switch (opCode) {
                case INST_EQ:
                  iResult = i == i2;
                  break;
                case INST_NEQ:
                  iResult = i != i2;
                  break;
                case INST_LT:
                  iResult = i < i2;
                  break;
                case INST_GT:
                  iResult = i > i2;
                  break;
                case INST_LE:
                  iResult = i <= i2;
                  break;
                case INST_GE:
                  iResult = i >= i2;
                  break;
                }
            }

            /*
             * Reuse the valuePtr object already on stack if possible.
             */
            
            if (Tcl_IsShared(valuePtr)) {
                PUSH_OBJECT(Tcl_NewLongObj(iResult));
                TRACE(("%s %.20s %.20s => %ld\n", opName[opCode],
                    O2S(valuePtr), O2S(value2Ptr), iResult));
                TclDecrRefCount(valuePtr);
            } else {    /* reuse the valuePtr object */
                TRACE(("%s %.20s %.20s => %ld\n",
                  opName[opCode], /* NB: stack top is off by 1 */
                    O2S(valuePtr), O2S(value2Ptr), iResult));
                Tcl_SetLongObj(valuePtr, iResult);
                ++stackTop; /* valuePtr now on stk top has right r.c. */
            }
            TclDecrRefCount(value2Ptr);
          }
          ADJUST_PC(1);
          
      case INST_MOD:
      case INST_LSHIFT:
      case INST_RSHIFT:
      case INST_BITOR:
      case INST_BITXOR:
      case INST_BITAND:
          {
            /*
             * Only integers are allowed. We compute value op value2.
             */

            long i2, rem, negative;
            long iResult = 0; /* Init. avoids compiler warning. */
            
            value2Ptr = POP_OBJECT();
            valuePtr  = POP_OBJECT(); 
            if (valuePtr->typePtr == &tclIntType) {
                i = valuePtr->internalRep.longValue;
            } else {    /* try to convert to int */
                result = Tcl_GetLongFromObj((Tcl_Interp *) NULL,
                      valuePtr, &i);
                if (result != TCL_OK) {
                  TRACE(("%s %.20s %.20s => ILLEGAL 1st TYPE %s\n",
                        opName[opCode], O2S(valuePtr), O2S(value2Ptr),
                        (valuePtr->typePtr?
                           valuePtr->typePtr->name : "null")));
                  IllegalExprOperandType(interp, opCode, valuePtr);
                  Tcl_DecrRefCount(valuePtr);
                  Tcl_DecrRefCount(value2Ptr);
                  goto checkForCatch;
                }
            }
            if (value2Ptr->typePtr == &tclIntType) {
                i2 = value2Ptr->internalRep.longValue;
            } else {
                result = Tcl_GetLongFromObj((Tcl_Interp *) NULL,
                      value2Ptr, &i2);
                if (result != TCL_OK) {
                  TRACE(("%s %.20s %.20s => ILLEGAL 2nd TYPE %s\n",
                        opName[opCode], O2S(valuePtr), O2S(value2Ptr),
                        (value2Ptr->typePtr?
                           value2Ptr->typePtr->name : "null")));
                  IllegalExprOperandType(interp, opCode, value2Ptr);
                  Tcl_DecrRefCount(valuePtr);
                  Tcl_DecrRefCount(value2Ptr);
                  goto checkForCatch;
                }
            }

            switch (opCode) {
            case INST_MOD:
                /*
                 * This code is tricky: C doesn't guarantee much about
                 * the quotient or remainder, but Tcl does. The
                 * remainder always has the same sign as the divisor and
                 * a smaller absolute value.
                 */
                if (i2 == 0) {
                  TRACE(("mod %ld %ld => DIVIDE BY ZERO\n", i, i2));
                  Tcl_DecrRefCount(valuePtr);
                  Tcl_DecrRefCount(value2Ptr);
                  goto divideByZero;
                }
                negative = 0;
                if (i2 < 0) {
                  i2 = -i2;
                  i = -i;
                  negative = 1;
                }
                rem  = i % i2;
                if (rem < 0) {
                  rem += i2;
                }
                if (negative) {
                  rem = -rem;
                }
                iResult = rem;
                break;
            case INST_LSHIFT:
                iResult = i << i2;
                break;
            case INST_RSHIFT:
                /*
                 * The following code is a bit tricky: it ensures that
                 * right shifts propagate the sign bit even on machines
                 * where ">>" won't do it by default.
                 */
                if (i < 0) {
                  iResult = ~((~i) >> i2);
                } else {
                  iResult = i >> i2;
                }
                break;
            case INST_BITOR:
                iResult = i | i2;
                break;
            case INST_BITXOR:
                iResult = i ^ i2;
                break;
            case INST_BITAND:
                iResult = i & i2;
                break;
            }

            /*
             * Reuse the valuePtr object already on stack if possible.
             */
            
            if (Tcl_IsShared(valuePtr)) {
                PUSH_OBJECT(Tcl_NewLongObj(iResult));
                TRACE(("%s %ld %ld => %ld\n", opName[opCode], i, i2,
                     iResult));
                TclDecrRefCount(valuePtr);
            } else {    /* reuse the valuePtr object */
                TRACE(("%s %ld %ld => %ld\n", opName[opCode], i, i2,
                    iResult)); /* NB: stack top is off by 1 */
                Tcl_SetLongObj(valuePtr, iResult);
                ++stackTop; /* valuePtr now on stk top has right r.c. */
            }
            TclDecrRefCount(value2Ptr);
          }
          ADJUST_PC(1);
          
      case INST_ADD:
      case INST_SUB:
      case INST_MULT:
      case INST_DIV:
          {
            /*
             * Operands must be numeric and ints get converted to floats
             * if necessary. We compute value op value2.
             */

            Tcl_ObjType *t1Ptr, *t2Ptr;
            long i2, quot, rem;
            double d1, d2;
            long iResult = 0;     /* Init. avoids compiler warning. */
            double dResult = 0.0; /* Init. avoids compiler warning. */
            int doDouble = 0;     /* 1 if doing floating arithmetic */
            
            value2Ptr = POP_OBJECT();
            valuePtr  = POP_OBJECT();
            t1Ptr = valuePtr->typePtr;
            t2Ptr = value2Ptr->typePtr;
            
            if (t1Ptr == &tclIntType) {
                i  = valuePtr->internalRep.longValue;
            } else if (t1Ptr == &tclDoubleType) {
                d1 = valuePtr->internalRep.doubleValue;
            } else {         /* try to convert; FAILS IF NULLS */
                char *s = Tcl_GetStringFromObj(valuePtr, &length);
                if (TclLooksLikeInt(s)) {
                  result = Tcl_GetLongFromObj((Tcl_Interp *) NULL,
                        valuePtr, &i);
                } else {
                  result = Tcl_GetDoubleFromObj((Tcl_Interp *) NULL,
                        valuePtr, &d1);
                }
                if (result != TCL_OK) {
                  TRACE(("%s %.20s %.20s => ILLEGAL 1st TYPE %s\n",
                         opName[opCode], s, O2S(value2Ptr),
                         (valuePtr->typePtr?
                            valuePtr->typePtr->name : "null")));
                  IllegalExprOperandType(interp, opCode, valuePtr);
                  Tcl_DecrRefCount(valuePtr);
                  Tcl_DecrRefCount(value2Ptr);
                  goto checkForCatch;
                }
                t1Ptr = valuePtr->typePtr;
            }
            
            if (t2Ptr == &tclIntType) {
                i2 = value2Ptr->internalRep.longValue;
            } else if (t2Ptr == &tclDoubleType) {
                d2 = value2Ptr->internalRep.doubleValue;
            } else {         /* try to convert; FAILS IF NULLS */
                char *s = Tcl_GetStringFromObj(value2Ptr, &length);
                if (TclLooksLikeInt(s)) {
                  result = Tcl_GetLongFromObj((Tcl_Interp *) NULL,
                        value2Ptr, &i2);
                } else {
                  result = Tcl_GetDoubleFromObj((Tcl_Interp *) NULL,
                        value2Ptr, &d2);
                }
                if (result != TCL_OK) {
                  TRACE(("%s %.20s %.20s => ILLEGAL 2nd TYPE %s\n",
                         opName[opCode], O2S(valuePtr), s,
                         (value2Ptr->typePtr?
                            value2Ptr->typePtr->name : "null")));
                  IllegalExprOperandType(interp, opCode, value2Ptr);
                  Tcl_DecrRefCount(valuePtr);
                  Tcl_DecrRefCount(value2Ptr);
                  goto checkForCatch;
                }
                t2Ptr = value2Ptr->typePtr;
            }

            if ((t1Ptr == &tclDoubleType) || (t2Ptr == &tclDoubleType)) {
                /*
                 * Do double arithmetic.
                 */
                doDouble = 1;
                if (t1Ptr == &tclIntType) {
                  d1 = i;       /* promote value 1 to double */
                } else if (t2Ptr == &tclIntType) {
                  d2 = i2;      /* promote value 2 to double */
                }
                switch (opCode) {
                case INST_ADD:
                  dResult = d1 + d2;
                  break;
                case INST_SUB:
                  dResult = d1 - d2;
                  break;
                case INST_MULT:
                  dResult = d1 * d2;
                  break;
                case INST_DIV:
                  if (d2 == 0.0) {
                      TRACE(("div %.6g %.6g => DIVIDE BY ZERO\n",
                           d1, d2));
                      Tcl_DecrRefCount(valuePtr);
                      Tcl_DecrRefCount(value2Ptr);
                      goto divideByZero;
                  }
                  dResult = d1 / d2;
                  break;
                }
                
                /*
                 * Check now for IEEE floating-point error.
                 */
                
                if (IS_NAN(dResult) || IS_INF(dResult)) {
                  TRACE(("%s %.20s %.20s => IEEE FLOATING PT ERROR\n",
                         opName[opCode], O2S(valuePtr), O2S(value2Ptr)));
                  TclExprFloatError(interp, dResult);
                  result = TCL_ERROR;
                  Tcl_DecrRefCount(valuePtr);
                  Tcl_DecrRefCount(value2Ptr);
                  goto checkForCatch;
                }
            } else {
                /*
                 * Do integer arithmetic.
                 */
                switch (opCode) {
                case INST_ADD:
                  iResult = i + i2;
                  break;
                case INST_SUB:
                  iResult = i - i2;
                  break;
                case INST_MULT:
                  iResult = i * i2;
                  break;
                case INST_DIV:
                  /*
                   * This code is tricky: C doesn't guarantee much
                   * about the quotient or remainder, but Tcl does.
                   * The remainder always has the same sign as the
                   * divisor and a smaller absolute value.
                   */
                  if (i2 == 0) {
                      TRACE(("div %ld %ld => DIVIDE BY ZERO\n",
                            i, i2));
                      Tcl_DecrRefCount(valuePtr);
                      Tcl_DecrRefCount(value2Ptr);
                      goto divideByZero;
                  }
                  if (i2 < 0) {
                      i2 = -i2;
                      i = -i;
                  }
                  quot = i / i2;
                  rem  = i % i2;
                  if (rem < 0) {
                      quot -= 1;
                  }
                  iResult = quot;
                  break;
                }
            }

            /*
             * Reuse the valuePtr object already on stack if possible.
             */
            
            if (Tcl_IsShared(valuePtr)) {
                if (doDouble) {
                  PUSH_OBJECT(Tcl_NewDoubleObj(dResult));
                  TRACE(("%s %.6g %.6g => %.6g\n", opName[opCode],
                         d1, d2, dResult));
                } else {
                  PUSH_OBJECT(Tcl_NewLongObj(iResult));
                  TRACE(("%s %ld %ld => %ld\n", opName[opCode],
                         i, i2, iResult));
                } 
                TclDecrRefCount(valuePtr);
            } else {        /* reuse the valuePtr object */
                if (doDouble) { /* NB: stack top is off by 1 */
                  TRACE(("%s %.6g %.6g => %.6g\n", opName[opCode],
                         d1, d2, dResult));
                  Tcl_SetDoubleObj(valuePtr, dResult);
                } else {
                  TRACE(("%s %ld %ld => %ld\n", opName[opCode],
                         i, i2, iResult));
                  Tcl_SetLongObj(valuePtr, iResult);
                }
                ++stackTop; /* valuePtr now on stk top has right r.c. */
            }
            TclDecrRefCount(value2Ptr);
          }
          ADJUST_PC(1);
          
      case INST_UPLUS:
          {
              /*
               * Operand must be numeric.
               */

            double d;
            Tcl_ObjType *tPtr;
            
            valuePtr = stackPtr[stackTop].o;
            tPtr = valuePtr->typePtr;
            if ((tPtr != &tclIntType) && (tPtr != &tclDoubleType)) {
                char *s = Tcl_GetStringFromObj(valuePtr, (int *) NULL);
                if (TclLooksLikeInt(s)) { /* FAILS IF NULLS */
                  result = Tcl_GetLongFromObj((Tcl_Interp *) NULL,
                        valuePtr, &i);
                } else {
                  result = Tcl_GetDoubleFromObj((Tcl_Interp *) NULL,
                        valuePtr, &d);
                }
                if (result != TCL_OK) { 
                  TRACE(("%s \"%.20s\" => ILLEGAL TYPE %s \n",
                          opName[opCode], s,
                          (tPtr? tPtr->name : "null")));
                  IllegalExprOperandType(interp, opCode, valuePtr);
                  goto checkForCatch;
                }
            }
            TRACE_WITH_OBJ(("uplus %s => ", O2S(valuePtr)), valuePtr);
          }
          ADJUST_PC(1);
          
      case INST_UMINUS:
      case INST_LNOT:
          {
            /*
             * The operand must be numeric. If the operand object is
             * unshared modify it directly, otherwise create a copy to
             * modify: this is "copy on write". free any old string
             * representation since it is now invalid.
             */
            
            double d;
            Tcl_ObjType *tPtr;
            
            valuePtr = POP_OBJECT();
            tPtr = valuePtr->typePtr;
            if ((tPtr != &tclIntType) && (tPtr != &tclDoubleType)) {
                char *s = Tcl_GetStringFromObj(valuePtr, (int *) NULL);
                if (TclLooksLikeInt(s)) { /* FAILS IF NULLS */
                  result = Tcl_GetLongFromObj((Tcl_Interp *) NULL,
                        valuePtr, &i);
                } else {
                  result = Tcl_GetDoubleFromObj((Tcl_Interp *) NULL,
                        valuePtr, &d);
                }
                if (result != TCL_OK) {
                  TRACE(("%s \"%.20s\" => ILLEGAL TYPE %s\n",
                          opName[opCode], s,
                         (tPtr? tPtr->name : "null")));
                  IllegalExprOperandType(interp, opCode, valuePtr);
                  Tcl_DecrRefCount(valuePtr);
                  goto checkForCatch;
                }
                tPtr = valuePtr->typePtr;
            }
            
            if (Tcl_IsShared(valuePtr)) {
                /*
                 * Create a new object.
                 */
                if (tPtr == &tclIntType) {
                  i = valuePtr->internalRep.longValue;
                  objPtr = Tcl_NewLongObj(
                          (opCode == INST_UMINUS)? -i : !i);
                  TRACE_WITH_OBJ(("%s %ld => ", opName[opCode], i),
                            objPtr); /* NB: stack top is off by 1 */
                } else {
                  d = valuePtr->internalRep.doubleValue;
                  if (opCode == INST_UMINUS) {
                      objPtr = Tcl_NewDoubleObj(-d);
                  } else {
                      /*
                       * Should be able to use "!d", but apparently
                       * some compilers can't handle it.
                       */
                      objPtr = Tcl_NewLongObj((d==0.0)? 1 : 0);
                  }
                  TRACE_WITH_OBJ(("%s %.6g => ", opName[opCode], d),
                            objPtr); /* NB: stack top is off by 1 */
                }
                PUSH_OBJECT(objPtr);
                TclDecrRefCount(valuePtr);
            } else {
                /*
                 * valuePtr is unshared. Modify it directly.
                 */
                if (tPtr == &tclIntType) {
                  i = valuePtr->internalRep.longValue;
                  Tcl_SetLongObj(valuePtr,
                          (opCode == INST_UMINUS)? -i : !i);
                  TRACE_WITH_OBJ(("%s %ld => ", opName[opCode], i),
                            valuePtr); /* NB: stack top is off by 1 */
                } else {
                  d = valuePtr->internalRep.doubleValue;
                  if (opCode == INST_UMINUS) {
                      Tcl_SetDoubleObj(valuePtr, -d);
                  } else {
                      /*
                       * Should be able to use "!d", but apparently
                       * some compilers can't handle it.
                       */
                      Tcl_SetLongObj(valuePtr, (d==0.0)? 1 : 0);
                  }
                  TRACE_WITH_OBJ(("%s %.6g => ", opName[opCode], d),
                            valuePtr); /* NB: stack top is off by 1 */
                }
                ++stackTop; /* valuePtr now on stk top has right r.c. */
            }
          }
          ADJUST_PC(1);
          
      case INST_BITNOT:
          {
            /*
             * The operand must be an integer. If the operand object is
             * unshared modify it directly, otherwise modify a copy. 
             * Free any old string representation since it is now
             * invalid.
             */
            
            Tcl_ObjType *tPtr;
            
            valuePtr = POP_OBJECT();
            tPtr = valuePtr->typePtr;
            if (tPtr != &tclIntType) {
                result = Tcl_GetLongFromObj((Tcl_Interp *) NULL,
                      valuePtr, &i);
                if (result != TCL_OK) {   /* try to convert to double */
                  TRACE(("bitnot \"%.20s\" => ILLEGAL TYPE %s\n",
                         O2S(valuePtr), (tPtr? tPtr->name : "null")));
                  IllegalExprOperandType(interp, opCode, valuePtr);
                  Tcl_DecrRefCount(valuePtr);
                  goto checkForCatch;
                }
            }
            
            i = valuePtr->internalRep.longValue;
            if (Tcl_IsShared(valuePtr)) {
                PUSH_OBJECT(Tcl_NewLongObj(~i));
                TRACE(("bitnot 0x%lx => (%lu)\n", i, ~i));
                TclDecrRefCount(valuePtr);
            } else {
                /*
                 * valuePtr is unshared. Modify it directly.
                 */
                Tcl_SetLongObj(valuePtr, ~i);
                ++stackTop; /* valuePtr now on stk top has right r.c. */
                TRACE(("bitnot 0x%lx => (%lu)\n", i, ~i));
            }
          }
          ADJUST_PC(1);
          
      case INST_CALL_BUILTIN_FUNC1:
          opnd = TclGetUInt1AtPtr(pc+1);
          {
            /*
             * Call one of the built-in Tcl math functions.
             */

            BuiltinFunc *mathFuncPtr;

            if ((opnd < 0) || (opnd > LAST_BUILTIN_FUNC)) {
                TRACE(("UNRECOGNIZED BUILTIN FUNC CODE %d\n", opnd));
                panic("TclExecuteByteCode: unrecognized builtin function code %d", opnd);
            }
            mathFuncPtr = &(builtinFuncTable[opnd]);
            DECACHE_STACK_INFO();
            tcl_MathInProgress++;
            result = (*mathFuncPtr->proc)(interp, eePtr,
                    mathFuncPtr->clientData);
            tcl_MathInProgress--;
            CACHE_STACK_INFO();
            if (result != TCL_OK) {
                goto checkForCatch;
            }
            TRACE_WITH_OBJ(("callBuiltinFunc1 %d => ", opnd),
                    stackPtr[stackTop].o);
          }
          ADJUST_PC(2);
                
      case INST_CALL_FUNC1:
          opnd = TclGetUInt1AtPtr(pc+1);
          {
            /*
             * Call a non-builtin Tcl math function previously
             * registered by a call to Tcl_CreateMathFunc.
             */
            
            int objc = opnd;   /* Number of arguments. The function name
                            * is the 0-th argument. */
            Tcl_Obj **objv;      /* The array of arguments. The function
                            * name is objv[0]. */
            
            objv = &(stackPtr[stackTop - (objc-1)].o); /* "objv[0]" */
            DECACHE_STACK_INFO();
            tcl_MathInProgress++;
            result = ExprCallMathFunc(interp, eePtr, objc, objv);
            tcl_MathInProgress--;
            CACHE_STACK_INFO();
            if (result != TCL_OK) {
                goto checkForCatch;
            }
            TRACE_WITH_OBJ(("callFunc1 %d => ", objc),
                    stackPtr[stackTop].o);
            ADJUST_PC(2);
          }

      case INST_TRY_CVT_TO_NUMERIC:
          {
            /*
             * Try to convert the topmost stack object to an int or
             * double object. This is done in order to support Tcl's
             * policy of interpreting operands if at all possible as
             * first integers, else floating-point numbers.
             */
            
            double d;
            char *s;
            Tcl_ObjType *tPtr;
            int converted, shared;

            valuePtr = stackPtr[stackTop].o;
            tPtr = valuePtr->typePtr;
            converted = 0;
            if ((tPtr != &tclIntType) && (tPtr != &tclDoubleType)) {
                s = Tcl_GetStringFromObj(valuePtr, (int *) NULL);
                if (TclLooksLikeInt(s)) { /* FAILS IF NULLS */
                  result = Tcl_GetLongFromObj((Tcl_Interp *) NULL,
                        valuePtr, &i);
                } else {
                  result = Tcl_GetDoubleFromObj((Tcl_Interp *) NULL,
                        valuePtr, &d);
                }
                if (result == TCL_OK) {
                  converted = 1;
                }
                result = TCL_OK; /* reset the result variable */
                tPtr = valuePtr->typePtr;
            }

            /*
             * Ensure that the topmost stack object, if numeric, 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. Also check if there has been an IEEE
             * floating point error.
             */

            if ((tPtr == &tclIntType) || (tPtr == &tclDoubleType)) {
                shared = 0;
                if (Tcl_IsShared(valuePtr)) {
                  shared = 1;
                  if (tPtr == &tclIntType) {
                      i = valuePtr->internalRep.longValue;
                      objPtr = Tcl_NewLongObj(i);
                  } else {
                      d = valuePtr->internalRep.doubleValue;
                      objPtr = Tcl_NewDoubleObj(d);
                  }
                  Tcl_IncrRefCount(objPtr);
                  TclDecrRefCount(valuePtr);
                  valuePtr = objPtr;
                  tPtr = valuePtr->typePtr;
                } else {
                  Tcl_InvalidateStringRep(valuePtr);
                }
                stackPtr[stackTop].o = valuePtr;
            
                if (tPtr == &tclDoubleType) {
                  d = valuePtr->internalRep.doubleValue;
                  if (IS_NAN(d) || IS_INF(d)) {
                      TRACE(("tryCvtToNumeric \"%.20s\" => IEEE FLOATING PT ERROR\n",
                             O2S(valuePtr)));
                      TclExprFloatError(interp, d);
                      result = TCL_ERROR;
                      goto checkForCatch;
                  }
                }
                shared = shared;          /* lint, shared not used. */
                converted = converted;    /* lint, converted not used. */
                TRACE(("tryCvtToNumeric \"%.20s\" => numeric, %s, %s\n",
                     O2S(valuePtr),
                     (converted? "converted" : "not converted"),
                     (shared? "shared" : "not shared")));
            } else {
                TRACE(("tryCvtToNumeric \"%.20s\" => not numeric\n",
                     O2S(valuePtr)));
            }
          }
          ADJUST_PC(1);

      case INST_BREAK:
          /*
           * First reset the interpreter's result. Then find the closest
           * enclosing loop or catch exception range, if any. If a loop is
           * found, terminate its execution. If the closest is a catch
           * exception range, jump to its catchOffset. If no enclosing
           * range is found, stop execution and return TCL_BREAK.
           */

          Tcl_ResetResult(interp);
          rangePtr = TclGetExceptionRangeForPc(pc, /*catchOnly*/ 0,
                codePtr);
          if (rangePtr == NULL) {
            TRACE(("break => no encl. loop or catch, returning TCL_BREAK\n"));
            result = TCL_BREAK;
            goto abnormalReturn; /* no catch exists to check */
          }
          switch (rangePtr->type) {
          case LOOP_EXCEPTION_RANGE:
            result = TCL_OK;
            TRACE(("break => range at %d, new pc %d\n",
                   rangePtr->codeOffset, rangePtr->breakOffset));
            break;
          case CATCH_EXCEPTION_RANGE:
            result = TCL_BREAK;
            TRACE(("break => ...\n"));
            goto processCatch; /* it will use rangePtr */
          default:
            panic("TclExecuteByteCode: unrecognized ExceptionRange type %d\n", rangePtr->type);
          }
          pc = (codePtr->codeStart + rangePtr->breakOffset);
          continue;     /* restart outer instruction loop at pc */

      case INST_CONTINUE:
            /*
           * Find the closest enclosing loop or catch exception range,
           * if any. If a loop is found, skip to its next iteration.
           * If the closest is a catch exception range, jump to its
           * catchOffset. If no enclosing range is found, stop
           * execution and return TCL_CONTINUE.
           */

          Tcl_ResetResult(interp);
          rangePtr = TclGetExceptionRangeForPc(pc, /*catchOnly*/ 0,
                codePtr);
          if (rangePtr == NULL) {
            TRACE(("continue => no encl. loop or catch, returning TCL_CONTINUE\n"));
            result = TCL_CONTINUE;
            goto abnormalReturn;
          }
          switch (rangePtr->type) {
          case LOOP_EXCEPTION_RANGE:
            if (rangePtr->continueOffset == -1) {
                TRACE(("continue => loop w/o continue, checking for catch\n"));
                goto checkForCatch;
            } else {
                result = TCL_OK;
                TRACE(("continue => range at %d, new pc %d\n",
                     rangePtr->codeOffset, rangePtr->continueOffset));
            }
            break;
          case CATCH_EXCEPTION_RANGE:
            result = TCL_CONTINUE;
            TRACE(("continue => ...\n"));
            goto processCatch; /* it will use rangePtr */
          default:
            panic("TclExecuteByteCode: unrecognized ExceptionRange type %d\n", rangePtr->type);
          }
          pc = (codePtr->codeStart + rangePtr->continueOffset);
          continue;     /* restart outer instruction loop at pc */

      case INST_FOREACH_START4:
          opnd = TclGetUInt4AtPtr(pc+1);
          {
              /*
             * Initialize the temporary local var that holds the count
             * of the number of iterations of the loop body to -1.
             */

            ForeachInfo *infoPtr = (ForeachInfo *)
                codePtr->auxDataArrayPtr[opnd].clientData;
            int iterTmpIndex = infoPtr->loopIterNumTmp;
            CallFrame *varFramePtr = iPtr->varFramePtr;
            Var *compiledLocals = varFramePtr->compiledLocals;
            Var *iterVarPtr;
            Tcl_Obj *oldValuePtr;

            iterVarPtr = &(compiledLocals[iterTmpIndex]);
            oldValuePtr = iterVarPtr->value.objPtr;
            if (oldValuePtr == NULL) {
                iterVarPtr->value.objPtr = Tcl_NewLongObj(-1);
                Tcl_IncrRefCount(iterVarPtr->value.objPtr);
            } else {
                Tcl_SetLongObj(oldValuePtr, -1);
            }
            TclSetVarScalar(iterVarPtr);
            TclClearVarUndefined(iterVarPtr);
            TRACE(("foreach_start4 %u => loop iter count temp %d\n", 
                    opnd, iterTmpIndex));
          }
          ADJUST_PC(5);
      
      case INST_FOREACH_STEP4:
          opnd = TclGetUInt4AtPtr(pc+1);
          {
              /*
             * "Step" a foreach loop (i.e., begin its next iteration) by
             * assigning the next value list element to each loop var.
             */

            ForeachInfo *infoPtr = (ForeachInfo *)
                codePtr->auxDataArrayPtr[opnd].clientData;
            ForeachVarList *varListPtr;
            int numLists = infoPtr->numLists;
            int iterTmpIndex = infoPtr->loopIterNumTmp;
            CallFrame *varFramePtr = iPtr->varFramePtr;
            Var *compiledLocals = varFramePtr->compiledLocals;
            int iterNum, listTmpIndex, listLen, numVars;
            int varIndex, valIndex, j;
            Tcl_Obj *listPtr, *elemPtr, *oldValuePtr;
            List *listRepPtr;
            Var *iterVarPtr, *listVarPtr;
            int continueLoop = 0;

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

            iterVarPtr = &(compiledLocals[iterTmpIndex]);
            oldValuePtr = iterVarPtr->value.objPtr;
            iterNum = (oldValuePtr->internalRep.longValue + 1);
            Tcl_SetLongObj(oldValuePtr, iterNum);
            
            /*
             * Check whether all value lists are exhausted and we should
             * stop the loop.
             */

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

                listVarPtr = &(compiledLocals[listTmpIndex]);
                listPtr = listVarPtr->value.objPtr;
                result = Tcl_ListObjLength(interp, listPtr, &listLen);
                if (result != TCL_OK) {
                  TRACE_WITH_OBJ(("foreach_step4 %u => ERROR converting list %ld, \"%s\": ",
                          opnd, i, O2S(listPtr)),
                        Tcl_GetObjResult(interp));
                  goto checkForCatch;
                }
                if (listLen > (iterNum * numVars)) {
                  continueLoop = 1;
                }
                listTmpIndex++;
            }

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

                  listVarPtr = &(compiledLocals[listTmpIndex]);
                  listPtr = listVarPtr->value.objPtr;
                  listRepPtr = (List *)
                          listPtr->internalRep.otherValuePtr;
                  listLen = listRepPtr->elemCount;
                  
                  valIndex = (iterNum * numVars);
                  for (j = 0;  j < numVars;  j++) {
                      int setEmptyStr = 0;
                      if (valIndex >= listLen) {
                        setEmptyStr = 1;
                        elemPtr = Tcl_NewObj();
                      } else {
                        elemPtr = listRepPtr->elements[valIndex];
                      }
                      
                      varIndex = varListPtr->varIndexes[j];
                      DECACHE_STACK_INFO();
                      value2Ptr = TclSetIndexedScalar(interp,
                             varIndex, elemPtr, /*leaveErrorMsg*/ 1);
                      CACHE_STACK_INFO();
                      if (value2Ptr == NULL) {
                        TRACE_WITH_OBJ(("foreach_step4 %u => ERROR init. index temp %d: ",
                               opnd, varIndex),
                               Tcl_GetObjResult(interp));
                        if (setEmptyStr) {
                            Tcl_DecrRefCount(elemPtr); /* unneeded */
                        }
                        result = TCL_ERROR;
                        goto checkForCatch;
                      }
                      valIndex++;
                  }
                  listTmpIndex++;
                }
            }
            
            /*
             * Now push a "1" object if at least one value list had a
             * remaining element and the loop should continue.
             * Otherwise push "0".
             */

            PUSH_OBJECT(Tcl_NewLongObj(continueLoop));
            TRACE(("foreach_step4 %u => %d lists, iter %d, %s loop\n", 
                    opnd, numLists, iterNum,
                    (continueLoop? "continue" : "exit")));
          }
          ADJUST_PC(5);

      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.
           */
          catchStackPtr[++catchTop] = stackTop;
          TRACE(("beginCatch4 %u => catchTop=%d, stackTop=%d\n",
                TclGetUInt4AtPtr(pc+1), catchTop, stackTop));
          ADJUST_PC(5);

      case INST_END_CATCH:
          catchTop--;
          result = TCL_OK;
          TRACE(("endCatch => catchTop=%d\n", catchTop));
          ADJUST_PC(1);

      case INST_PUSH_RESULT:
          PUSH_OBJECT(Tcl_GetObjResult(interp));
          TRACE_WITH_OBJ(("pushResult => "), Tcl_GetObjResult(interp));
          ADJUST_PC(1);

      case INST_PUSH_RETURN_CODE:
          PUSH_OBJECT(Tcl_NewLongObj(result));
          TRACE(("pushReturnCode => %u\n", result));
          ADJUST_PC(1);

      default:
          TRACE(("UNRECOGNIZED INSTRUCTION %u\n", opCode));
          panic("TclExecuteByteCode: unrecognized opCode %u", opCode);
      } /* end of switch on opCode */

      /*
       * Division by zero in an expression. Control only reaches this
       * point by "goto divideByZero".
       */
      
        divideByZero:
      Tcl_ResetResult(interp);
      Tcl_AppendToObj(Tcl_GetObjResult(interp), "divide by zero", -1);
      Tcl_SetErrorCode(interp, "ARITH", "DIVZERO", "divide by zero",
                   (char *) NULL);
      result = TCL_ERROR;
      
      /*
       * 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)) {
          RecordTracebackInfo(interp, pc, codePtr);
        }
      rangePtr = TclGetExceptionRangeForPc(pc, /*catchOnly*/ 1, codePtr);
      if (rangePtr == NULL) {
          TRACE(("   ... no enclosing catch, returning %s\n",
                StringForResultCode(result)));
          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 (stackTop > catchStackPtr[catchTop]) {
          valuePtr = POP_OBJECT();
          TclDecrRefCount(valuePtr);
      }
      TRACE(("  ... found catch at %d, catchTop=%d, unwound to %d, new pc %u\n",
              rangePtr->codeOffset, catchTop, catchStackPtr[catchTop],
              (unsigned int)(rangePtr->catchOffset)));
      pc = (codePtr->codeStart + rangePtr->catchOffset);
      continue;         /* 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.
     */

    abnormalReturn:
    while (stackTop > initStackTop) {
      valuePtr = POP_OBJECT();
      Tcl_DecrRefCount(valuePtr);
    }

    /*
     * Free the catch stack array if malloc'ed storage was used.
     */

    done:
    if (catchStackPtr != catchStackStorage) {
      ckfree((char *) catchStackPtr);
    }
    eePtr->stackTop = initStackTop;
    return result;
#undef STATIC_CATCH_STACK_SIZE
}

/*
 *----------------------------------------------------------------------
 *
 * 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(codePtr)
    register ByteCode *codePtr;     /* The bytecode whose summary is printed
                         * to stdout. */
{
    Proc *procPtr = codePtr->procPtr;
    int numCmds = codePtr->numCommands;
    int numObjs = codePtr->numObjects;
    int objBytes, i;

    objBytes = (numObjs * sizeof(Tcl_Obj));
    for (i = 0;  i < numObjs;  i++) {
      Tcl_Obj *litObjPtr = codePtr->objArrayPtr[i];
      if (litObjPtr->bytes != NULL) {
          objBytes += litObjPtr->length;
      }
    }
    
    fprintf(stdout, "\nExecuting ByteCode 0x%x, ref ct %u, epoch %u, interp 0x%x(epoch %u)\n",
          (unsigned int) codePtr, codePtr->refCount,
          codePtr->compileEpoch, (unsigned int) codePtr->iPtr,
          codePtr->iPtr->compileEpoch);
    
    fprintf(stdout, "  Source: ");
    TclPrintSource(stdout, codePtr->source, 70);

    fprintf(stdout, "\n  Cmds %d, chars %d, inst %u, objs %u, aux %d, stk depth %u, code/src %.2fn",
            numCmds, codePtr->numSrcChars, codePtr->numCodeBytes, numObjs,
          codePtr->numAuxDataItems, codePtr->maxStackDepth,
          (codePtr->numSrcChars?
                  ((float)codePtr->totalSize)/((float)codePtr->numSrcChars) : 0.0));

    fprintf(stdout, "  Code %d = %d(header)+%d(inst)+%d(objs)+%d(exc)+%d(aux)+%d(cmd map)\n",
          codePtr->totalSize, sizeof(ByteCode), codePtr->numCodeBytes,
          objBytes, (codePtr->numExcRanges * sizeof(ExceptionRange)),
          (codePtr->numAuxDataItems * sizeof(AuxData)),
          codePtr->numCmdLocBytes);

    if (procPtr != NULL) {
      fprintf(stdout,
            "  Proc 0x%x, ref ct %d, args %d, compiled locals %d\n",
            (unsigned int) procPtr, procPtr->refCount,
            procPtr->numArgs, procPtr->numCompiledLocals);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * 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(codePtr, pc, stackTop, stackLowerBound, stackUpperBound)
    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 stackUpperBound;      /* Greatest legal value for stackTop. */
{
    unsigned int relativePc = (unsigned int) (pc - codePtr->codeStart);
    unsigned int codeStart = (unsigned int) codePtr->codeStart;
    unsigned int codeEnd = (unsigned int)
          (codePtr->codeStart + codePtr->numCodeBytes);
    unsigned char opCode = *pc;

    if (((unsigned int) pc < codeStart) || ((unsigned int) pc > codeEnd)) {
      fprintf(stderr, "\nBad instruction pc 0x%x in TclExecuteByteCode\n",
            (unsigned int) pc);
      panic("TclExecuteByteCode execution failure: bad pc");
    }
    if ((unsigned int) opCode > LAST_INST_OPCODE) {
      fprintf(stderr, "\nBad opcode %d at pc %u in TclExecuteByteCode\n",
            (unsigned int) opCode, relativePc);
      panic("TclExecuteByteCode execution failure: bad opcode");
    }
    if ((stackTop < stackLowerBound) || (stackTop > stackUpperBound)) {
      int numChars;
      char *cmd = GetSrcInfoForPc(pc, codePtr, &numChars);
      char *ellipsis = "";
      
      fprintf(stderr, "\nBad stack top %d at pc %u in TclExecuteByteCode",
            stackTop, relativePc);
      if (cmd != NULL) {
          if (numChars > 100) {
            numChars = 100;
            ellipsis = "...";
          }
          fprintf(stderr, "\n executing %.*s%s\n", numChars, cmd,
                ellipsis);
      } else {
          fprintf(stderr, "\n");
      }
      panic("TclExecuteByteCode execution failure: bad stack top");
    }
}
#endif /* TCL_COMPILE_DEBUG */

/*
 *----------------------------------------------------------------------
 *
 * IllegalExprOperandType --
 *
 *    Used by TclExecuteByteCode to add an error message to errorInfo
 *    when an illegal operand type is detected by an expression
 *    instruction. The argument opCode holds the failing instruction's
 *    opcode and opndPtr holds the operand object in error.
 *
 * Results:
 *    None.
 *
 * Side effects:
 *    An error message is appended to errorInfo.
 *
 *----------------------------------------------------------------------
 */

static void
IllegalExprOperandType(interp, opCode, opndPtr)
    Tcl_Interp *interp;       /* Interpreter to which error information
                         * pertains. */
    unsigned int opCode;      /* The instruction opcode being executed
                         * when the illegal type was found. */
    Tcl_Obj *opndPtr;         /* Points to the operand holding the value
                         * with the illegal type. */
{
    Tcl_ResetResult(interp);
    if ((opndPtr->bytes == NULL) || (opndPtr->length == 0)) {
      Tcl_AppendStringsToObj(Tcl_GetObjResult(interp),
            "can't use empty string as operand of \"",
            operatorStrings[opCode - INST_LOR], "\"", (char *) NULL);
    } else {
      Tcl_AppendStringsToObj(Tcl_GetObjResult(interp), "can't use ",
            ((opndPtr->typePtr == &tclDoubleType) ?
                "floating-point value" : "non-numeric string"),
            " as operand of \"", operatorStrings[opCode - INST_LOR],
            "\"", (char *) NULL);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * CallTraceProcedure --
 *
 *    Invokes a trace procedure registered with an interpreter. These
 *    procedures trace command execution. Currently this trace procedure
 *    is called with the address of the string-based Tcl_CmdProc for the
 *    command, not the Tcl_ObjCmdProc.
 *
 * Results:
 *    None.
 *
 * Side effects:
 *    Those side effects made by the trace procedure.
 *
 *----------------------------------------------------------------------
 */

static void
CallTraceProcedure(interp, tracePtr, cmdPtr, command, numChars, objc, objv)
    Tcl_Interp *interp;       /* The current interpreter. */
    register Trace *tracePtr; /* Describes the trace procedure to call. */
    Command *cmdPtr;          /* Points to command's Command struct. */
    char *command;            /* Points to the first character of the
                         * command's source before substitutions. */
    int numChars;       /* The number of characters in the
                         * command's source. */
    register int objc;        /* Number of arguments for the command. */
    Tcl_Obj *objv[];          /* Pointers to Tcl_Obj of each argument. */
{
    Interp *iPtr = (Interp *) interp;
    register char **argv;
    register int i;
    int length;
    char *p;

    /*
     * Get the string rep from the objv argument objects and place their
     * pointers in argv. First make sure argv is large enough to hold the
     * objc args plus 1 extra word for the zero end-of-argv word.
     * THIS FAILS IF AN OBJECT'S STRING REP CONTAINS NULLS.
     */
    
    argv = (char **) ckalloc((unsigned)(objc + 1) * sizeof(char *));
    for (i = 0;  i < objc;  i++) {
      argv[i] = Tcl_GetStringFromObj(objv[i], &length);
    }
    argv[objc] = 0;

    /*
     * Copy the command characters into a new string.
     */

    p = (char *) ckalloc((unsigned) (numChars + 1));
    memcpy((VOID *) p, (VOID *) command, (size_t) numChars);
    p[numChars] = '\0';
    
    /*
     * Call the trace procedure then free allocated storage.
     */
    
    (*tracePtr->proc)(tracePtr->clientData, interp, iPtr->numLevels,
                      p, cmdPtr->proc, cmdPtr->clientData, objc, argv);

    ckfree((char *) argv);
    ckfree((char *) p);
}

/*
 *----------------------------------------------------------------------
 *
 * RecordTracebackInfo --
 *
 *      Procedure called by TclExecuteByteCode to record information
 *      about what was being executed when the error occurred.
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      Appends information about the command being executed to the
 *      "errorInfo" variable. Sets the errorLine field in the interpreter
 *      to the line number of that command. Sets the ERR_ALREADY_LOGGED
 *      bit in the interpreter's execution flags.
 *
 *----------------------------------------------------------------------
 */

static void
RecordTracebackInfo(interp, pc, codePtr)
    Tcl_Interp *interp;         /* The interpreter in which the error
                                 * occurred. */
    unsigned char *pc;          /* The program counter value where the error                                 * occurred. This points to a bytecode
                                 * instruction in codePtr's code. */
    ByteCode *codePtr;          /* The bytecode sequence being executed. */
{
    register Interp *iPtr = (Interp *) interp;
    char *cmd, *ellipsis;
    char buf[200];
    register char *p;
    int numChars;
    
    /*
     * Record the command in errorInfo (up to a certain number of
     * characters, or up to the first newline).
     */
    
    iPtr->errorLine = 1;
    cmd = GetSrcInfoForPc(pc, codePtr, &numChars);
    if (cmd != NULL) {
        for (p = codePtr->source;  p != cmd;  p++) {
            if (*p == '\n') {
                iPtr->errorLine++;
            }
        }
        for ( ;  (isspace(UCHAR(*p)) || (*p == ';'));  p++) {
            if (*p == '\n') {
                iPtr->errorLine++;
            }
        }
      
        ellipsis = "";
        if (numChars > 150) {
            numChars = 150;
            ellipsis = "...";
        }
        if (!(iPtr->flags & ERR_IN_PROGRESS)) {
            sprintf(buf, "\n    while executing\n\"%.*s%s\"",
                    numChars, cmd, ellipsis);
        } else {
            sprintf(buf, "\n    invoked from within\n\"%.*s%s\"",
                    numChars, cmd, ellipsis);
        }
        Tcl_AddObjErrorInfo(interp, buf, -1);
        iPtr->flags |= ERR_ALREADY_LOGGED;
    }
}

/*
 *----------------------------------------------------------------------
 *
 * GetSrcInfoForPc --
 *
 *    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:
 *    None.
 *
 *----------------------------------------------------------------------
 */

static char *
GetSrcInfoForPc(pc, codePtr, lengthPtr)
    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 int) (*codeDeltaNext) == (unsigned int) 0xFF) {
          codeDeltaNext++;
          delta = TclGetInt4AtPtr(codeDeltaNext);
          codeDeltaNext += 4;
      } else {
          delta = TclGetInt1AtPtr(codeDeltaNext);
          codeDeltaNext++;
      }
      codeOffset += delta;

      if ((unsigned int) (*codeLengthNext) == (unsigned int) 0xFF) {
          codeLengthNext++;
          codeLen = TclGetInt4AtPtr(codeLengthNext);
          codeLengthNext += 4;
      } else {
          codeLen = TclGetInt1AtPtr(codeLengthNext);
          codeLengthNext++;
      }
      codeEnd = (codeOffset + codeLen - 1);

      if ((unsigned int) (*srcDeltaNext) == (unsigned int) 0xFF) {
          srcDeltaNext++;
          delta = TclGetInt4AtPtr(srcDeltaNext);
          srcDeltaNext += 4;
      } else {
          delta = TclGetInt1AtPtr(srcDeltaNext);
          srcDeltaNext++;
      }
      srcOffset += delta;

      if ((unsigned int) (*srcLengthNext) == (unsigned int) 0xFF) {
          srcLengthNext++;
          srcLen = TclGetInt4AtPtr(srcLengthNext);
          srcLengthNext += 4;
      } else {
          srcLen = TclGetInt1AtPtr(srcLengthNext);
          srcLengthNext++;
      }
      
      if (codeOffset > pcOffset) {      /* best cmd already found */
          break;
      } else 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);
}

/*
 *----------------------------------------------------------------------
 *
 * TclGetExceptionRangeForPc --
 *
 *    Procedure that given a program counter value, returns the closest
 *    enclosing ExceptionRange that matches the kind requested.
 *
 * Results:
 *    In the normal case, catchOnly is 0 (false) and this procedure
 *    returns a pointer to the most closely enclosing ExceptionRange
 *    structure regardless of whether it is a loop or catch exception
 *    range. This is appropriate when processing a TCL_BREAK or
 *    TCL_CONTINUE, which will be "handled" either by a loop exception
 *    range or a closer catch range. If catchOnly is nonzero (true), this
 *    procedure ignores loop exception ranges and returns a pointer to the
 *    closest catch range. If no matching ExceptionRange is found that
 *    encloses pc, a NULL is returned.
 *
 * Side effects:
 *    None.
 *
 *----------------------------------------------------------------------
 */

ExceptionRange *
TclGetExceptionRangeForPc(pc, catchOnly, codePtr)
    unsigned char *pc;        /* The program counter value for which to
                         * search for a closest enclosing exception
                         * range. This points to a bytecode
                         * instruction in codePtr's code. */
    int catchOnly;            /* If 0, consider either loop or catch
                         * ExceptionRanges in search. Otherwise
                         * consider only catch ranges (and ignore
                         * any closer loop ranges). */
    ByteCode* codePtr;        /* Points to the ByteCode in which to search
                         * for the enclosing ExceptionRange. */
{
    ExceptionRange *rangeArrayPtr = codePtr->excRangeArrayPtr;
    int numRanges = codePtr->numExcRanges;
    register ExceptionRange *rangePtr;
    int codeOffset = (pc - codePtr->codeStart);
    register int i, level;

    for (level = codePtr->maxExcRangeDepth;  level >= 0;  level--) {
      for (i = 0;  i < numRanges;  i++) {
          rangePtr = &(rangeArrayPtr[i]);
          if (rangePtr->nestingLevel == level) {
            int start = rangePtr->codeOffset;
            int end   = (start + rangePtr->numCodeBytes);
            if ((start <= codeOffset) && (codeOffset < end)) {
                if ((!catchOnly)
                      || (rangePtr->type == CATCH_EXCEPTION_RANGE)) {
                  return rangePtr;
                }
            }
          }
      }
    }
    return NULL;
}

/*
 *----------------------------------------------------------------------
 *
 * Math Functions --
 *
 *    This page contains the procedures that implement all of the
 *    built-in math functions for expressions.
 *
 * Results:
 *    Each procedure returns TCL_OK if it succeeds and pushes an
 *    Tcl object holding the result. If it fails it returns TCL_ERROR
 *    and leaves an error message in the interpreter's result.
 *
 * Side effects:
 *    None.
 *
 *----------------------------------------------------------------------
 */

static int
ExprUnaryFunc(interp, eePtr, clientData)
    Tcl_Interp *interp;       /* The interpreter in which to execute the
                         * function. */
    ExecEnv *eePtr;           /* Points to the environment for executing
                         * the function. */
    ClientData clientData;    /* Contains the address of a procedure that
                         * takes one double argument and returns a
                         * double result. */
{
    StackItem *stackPtr;        /* Cached evaluation stack base pointer. */
    register int stackTop;    /* Cached top index of evaluation stack. */
    register Tcl_Obj *valuePtr;
    Tcl_ObjType *tPtr;
    double d, dResult;
    long i;
    int result = TCL_OK;
    
    double (*func) _ANSI_ARGS_((double)) =
      (double (*)_ANSI_ARGS_((double))) clientData;

    /*
     * Set stackPtr and stackTop from eePtr.
     */
    
    CACHE_STACK_INFO();

    /*
     * Pop the function's argument from the evaluation stack. Convert it
     * to a double if necessary.
     */

    valuePtr = POP_OBJECT();
    tPtr = valuePtr->typePtr;
    
    if (tPtr == &tclIntType) {
      d = (double) valuePtr->internalRep.longValue;
    } else if (tPtr == &tclDoubleType) {
      d = valuePtr->internalRep.doubleValue;
    } else {                  /* FAILS IF STRING REP HAS NULLS */
      char *s = Tcl_GetStringFromObj(valuePtr, (int *) NULL);
      
      if (TclLooksLikeInt(s)) {
          result = Tcl_GetLongFromObj((Tcl_Interp *) NULL, valuePtr, &i);
          d = (double) valuePtr->internalRep.longValue;
      } else {
          result = Tcl_GetDoubleFromObj((Tcl_Interp *) NULL, valuePtr, &d);
      }
      if (result != TCL_OK) {
          Tcl_ResetResult(interp);
          Tcl_AppendToObj(Tcl_GetObjResult(interp),
                  "argument to math function didn't have numeric value", -1);
          goto done;
      }
    }

    errno = 0;
    dResult = (*func)(d);
    if ((errno != 0) || IS_NAN(dResult) || IS_INF(dResult)) {
      TclExprFloatError(interp, dResult);
      result = TCL_ERROR;
      goto done;
    }
    
    /*
     * Push a Tcl object holding the result.
     */

    PUSH_OBJECT(Tcl_NewDoubleObj(dResult));
    
    /*
     * Reflect the change to stackTop back in eePtr.
     */

    done:
    Tcl_DecrRefCount(valuePtr);
    DECACHE_STACK_INFO();
    return result;
}

static int
ExprBinaryFunc(interp, eePtr, clientData)
    Tcl_Interp *interp;       /* The interpreter in which to execute the
                         * function. */
    ExecEnv *eePtr;           /* Points to the environment for executing
                         * the function. */
    ClientData clientData;    /* Contains the address of a procedure that
                         * takes two double arguments and
                         * returns a double result. */
{
    StackItem *stackPtr;        /* Cached evaluation stack base pointer. */
    register int stackTop;    /* Cached top index of evaluation stack. */
    register Tcl_Obj *valuePtr, *value2Ptr;
    Tcl_ObjType *tPtr;
    double d1, d2, dResult;
    long i;
    char *s;
    int result = TCL_OK;
    
    double (*func) _ANSI_ARGS_((double, double))
      = (double (*)_ANSI_ARGS_((double, double))) clientData;

    /*
     * Set stackPtr and stackTop from eePtr.
     */
    
    CACHE_STACK_INFO();

    /*
     * Pop the function's two arguments from the evaluation stack. Convert
     * them to doubles if necessary.
     */

    value2Ptr = POP_OBJECT();
    valuePtr  = POP_OBJECT();

    tPtr = valuePtr->typePtr;
    if (tPtr == &tclIntType) {
      d1 = (double) valuePtr->internalRep.longValue;
    } else if (tPtr == &tclDoubleType) {
      d1 = valuePtr->internalRep.doubleValue;
    } else {                  /* FAILS IF STRING REP HAS NULLS */
      s = Tcl_GetStringFromObj(valuePtr, (int *) NULL);
      if (TclLooksLikeInt(s)) {
          result = Tcl_GetLongFromObj((Tcl_Interp *) NULL, valuePtr, &i);
          d1 = (double) valuePtr->internalRep.longValue;
      } else {
          result = Tcl_GetDoubleFromObj((Tcl_Interp *) NULL, valuePtr, &d1);
      }
      if (result != TCL_OK) {
            badArg:
          Tcl_ResetResult(interp);
          Tcl_AppendToObj(Tcl_GetObjResult(interp),
                  "argument to math function didn't have numeric value", -1);
          goto done;
      }
    }

    tPtr = value2Ptr->typePtr;
    if (tPtr == &tclIntType) {
      d2 = value2Ptr->internalRep.longValue;
    } else if (tPtr == &tclDoubleType) {
      d2 = value2Ptr->internalRep.doubleValue;
    } else {                  /* FAILS IF STRING REP HAS NULLS */
      s = Tcl_GetStringFromObj(value2Ptr, (int *) NULL);
      if (TclLooksLikeInt(s)) {
          result = Tcl_GetLongFromObj((Tcl_Interp *) NULL, value2Ptr, &i);
          d2 = (double) value2Ptr->internalRep.longValue;
      } else {
          result = Tcl_GetDoubleFromObj((Tcl_Interp *) NULL, value2Ptr, &d2);
      }
      if (result != TCL_OK) {
          goto badArg;
      }
    }

    errno = 0;
    dResult = (*func)(d1, d2);
    if ((errno != 0) || IS_NAN(dResult) || IS_INF(dResult)) {
      TclExprFloatError(interp, dResult);
      result = TCL_ERROR;
      goto done;
    }

    /*
     * Push a Tcl object holding the result.
     */

    PUSH_OBJECT(Tcl_NewDoubleObj(dResult));
    
    /*
     * Reflect the change to stackTop back in eePtr.
     */

    done:
    Tcl_DecrRefCount(valuePtr);
    Tcl_DecrRefCount(value2Ptr);
    DECACHE_STACK_INFO();
    return result;
}

static int
ExprAbsFunc(interp, eePtr, clientData)
    Tcl_Interp *interp;       /* The interpreter in which to execute the
                         * function. */
    ExecEnv *eePtr;           /* Points to the environment for executing
                         * the function. */
    ClientData clientData;    /* Ignored. */
{
    StackItem *stackPtr;        /* Cached evaluation stack base pointer. */
    register int stackTop;    /* Cached top index of evaluation stack. */
    register Tcl_Obj *valuePtr;
    Tcl_ObjType *tPtr;
    long i, iResult;
    double d, dResult;
    int result = TCL_OK;

    /*
     * Set stackPtr and stackTop from eePtr.
     */
    
    CACHE_STACK_INFO();

    /*
     * Pop the argument from the evaluation stack.
     */

    valuePtr = POP_OBJECT();
    tPtr = valuePtr->typePtr;
    
    if (tPtr == &tclIntType) {
      i = valuePtr->internalRep.longValue;
    } else if (tPtr == &tclDoubleType) {
      d = valuePtr->internalRep.doubleValue;
    } else {                  /* FAILS IF STRING REP HAS NULLS */
      char *s = Tcl_GetStringFromObj(valuePtr, (int *) NULL);
      
      if (TclLooksLikeInt(s)) {
          result = Tcl_GetLongFromObj((Tcl_Interp *) NULL, valuePtr, &i);
      } else {
          result = Tcl_GetDoubleFromObj((Tcl_Interp *) NULL, valuePtr, &d);
      }
      if (result != TCL_OK) {
          Tcl_ResetResult(interp);
          Tcl_AppendToObj(Tcl_GetObjResult(interp),
                  "argument to math function didn't have numeric value", -1);
          goto done;
      }
      tPtr = valuePtr->typePtr;
    }

    /*
     * Push a Tcl object with the result.
     */
    
    if (tPtr == &tclIntType) {
      if (i < 0) {
          iResult = -i;
          if (iResult < 0) {
            Tcl_ResetResult(interp);
            Tcl_AppendToObj(Tcl_GetObjResult(interp),
                    "integer value too large to represent", -1);
            Tcl_SetErrorCode(interp, "ARITH", "IOVERFLOW",
                  "integer value too large to represent", (char *) NULL);
            result = TCL_ERROR;
            goto done;
          }
      } else {
          iResult = i;
      }         
      PUSH_OBJECT(Tcl_NewLongObj(iResult));
    } else {
      if (d < 0.0) {
          dResult = -d;
      } else {
          dResult = d;
      }
      if (IS_NAN(dResult) || IS_INF(dResult)) {
          TclExprFloatError(interp, dResult);
          result = TCL_ERROR;
          goto done;
      }
      PUSH_OBJECT(Tcl_NewDoubleObj(dResult));
    }
    
    /*
     * Reflect the change to stackTop back in eePtr.
     */

    done:
    Tcl_DecrRefCount(valuePtr);
    DECACHE_STACK_INFO();
    return result;
}

static int
ExprDoubleFunc(interp, eePtr, clientData)
    Tcl_Interp *interp;       /* The interpreter in which to execute the
                         * function. */
    ExecEnv *eePtr;           /* Points to the environment for executing
                         * the function. */
    ClientData clientData;    /* Ignored. */
{
    StackItem *stackPtr;        /* Cached evaluation stack base pointer. */
    register int stackTop;    /* Cached top index of evaluation stack. */
    register Tcl_Obj *valuePtr;
    double dResult;
    long i;
    int result = TCL_OK;

    /*
     * Set stackPtr and stackTop from eePtr.
     */
    
    CACHE_STACK_INFO();

    /*
     * Pop the argument from the evaluation stack.
     */

    valuePtr = POP_OBJECT();
    if (valuePtr->typePtr == &tclIntType) {
      dResult = (double) valuePtr->internalRep.longValue;
    } else if (valuePtr->typePtr == &tclDoubleType) {
      dResult = valuePtr->internalRep.doubleValue;
    } else {                  /* FAILS IF STRING REP HAS NULLS */
      char *s = Tcl_GetStringFromObj(valuePtr, (int *) NULL);
      
      if (TclLooksLikeInt(s)) {
          result = Tcl_GetLongFromObj((Tcl_Interp *) NULL, valuePtr, &i);
          dResult = (double) valuePtr->internalRep.longValue;
      } else {
          result = Tcl_GetDoubleFromObj((Tcl_Interp *) NULL, valuePtr,
                &dResult);
      }
      if (result != TCL_OK) {
          Tcl_ResetResult(interp);
          Tcl_AppendToObj(Tcl_GetObjResult(interp),
                "argument to math function didn't have numeric value", -1);
          goto done;
      }
    }

    /*
     * Push a Tcl object with the result.
     */

    PUSH_OBJECT(Tcl_NewDoubleObj(dResult));

    /*
     * Reflect the change to stackTop back in eePtr.
     */

    done:
    Tcl_DecrRefCount(valuePtr);
    DECACHE_STACK_INFO();
    return result;
}

static int
ExprIntFunc(interp, eePtr, clientData)
    Tcl_Interp *interp;       /* The interpreter in which to execute the
                         * function. */
    ExecEnv *eePtr;           /* Points to the environment for executing
                         * the function. */
    ClientData clientData;    /* Ignored. */
{
    StackItem *stackPtr;        /* Cached evaluation stack base pointer. */
    register int stackTop;    /* Cached top index of evaluation stack. */
    register Tcl_Obj *valuePtr;
    Tcl_ObjType *tPtr;
    long i = 0;               /* Initialized to avoid compiler warning. */
    long iResult;
    double d;
    int result = TCL_OK;

    /*
     * Set stackPtr and stackTop from eePtr.
     */
    
    CACHE_STACK_INFO();

    /*
     * Pop the argument from the evaluation stack.
     */

    valuePtr = POP_OBJECT();
    tPtr = valuePtr->typePtr;
    
    if (tPtr == &tclIntType) {
      i = valuePtr->internalRep.longValue;
    } else if (tPtr == &tclDoubleType) {
      d = valuePtr->internalRep.doubleValue;
    } else {                  /* FAILS IF STRING REP HAS NULLS */
      char *s = Tcl_GetStringFromObj(valuePtr, (int *) NULL);
      
      if (TclLooksLikeInt(s)) {
          result = Tcl_GetLongFromObj((Tcl_Interp *) NULL, valuePtr, &i);
      } else {
          result = Tcl_GetDoubleFromObj((Tcl_Interp *) NULL, valuePtr, &d);
      }
      if (result != TCL_OK) {
          Tcl_ResetResult(interp);
          Tcl_AppendToObj(Tcl_GetObjResult(interp),
                "argument to math function didn't have numeric value", -1);
          goto done;
      }
      tPtr = valuePtr->typePtr;
    }

    /*
     * Push a Tcl object with the result.
     */
    
    if (tPtr == &tclIntType) {
      iResult = i;
    } else {
      if (d < 0.0) {
          if (d < (double) (long) LONG_MIN) {
            tooLarge:
            Tcl_ResetResult(interp);
            Tcl_AppendToObj(Tcl_GetObjResult(interp),
                    "integer value too large to represent", -1);
            Tcl_SetErrorCode(interp, "ARITH", "IOVERFLOW",
                  "integer value too large to represent", (char *) NULL);
            result = TCL_ERROR;
            goto done;
          }
      } else {
          if (d > (double) LONG_MAX) {
            goto tooLarge;
          }
      }
      if (IS_NAN(d) || IS_INF(d)) {
          TclExprFloatError(interp, d);
          result = TCL_ERROR;
          goto done;
      }
      iResult = (long) d;
    }
    PUSH_OBJECT(Tcl_NewLongObj(iResult));

    /*
     * Reflect the change to stackTop back in eePtr.
     */

    done:
    Tcl_DecrRefCount(valuePtr);
    DECACHE_STACK_INFO();
    return result;
}

static int
ExprRandFunc(interp, eePtr, clientData)
    Tcl_Interp *interp;       /* The interpreter in which to execute the
                         * function. */
    ExecEnv *eePtr;           /* Points to the environment for executing
                         * the function. */
    ClientData clientData;    /* Ignored. */
{
    StackItem *stackPtr;        /* Cached evaluation stack base pointer. */
    register int stackTop;    /* Cached top index of evaluation stack. */
    Interp *iPtr = (Interp *) interp;
    double dResult;
    int tmp;

    if (!(iPtr->flags & RAND_SEED_INITIALIZED)) {
      iPtr->flags |= RAND_SEED_INITIALIZED;
      iPtr->randSeed = TclpGetClicks();
    }
    
    /*
     * Set stackPtr and stackTop from eePtr.
     */
    
    CACHE_STACK_INFO();

    /*
     * Generate the random number using the linear congruential
     * generator defined by the following recurrence:
     *            seed = ( IA * seed ) mod IM
     * where IA is 16807 and IM is (2^31) - 1.  In order to avoid
     * potential problems with integer overflow, the  code uses
     * additional constants IQ and IR such that
     *            IM = IA*IQ + IR
     * For details on how this algorithm works, refer to the following
     * papers: 
     *
     *      S.K. Park & K.W. Miller, "Random number generators: good ones
     *      are hard to find," Comm ACM 31(10):1192-1201, Oct 1988
     *
     *      W.H. Press & S.A. Teukolsky, "Portable random number
     *      generators," Computers in Physics 6(5):522-524, Sep/Oct 1992.
     */

#define RAND_IA         16807
#define RAND_IM         2147483647
#define RAND_IQ         127773
#define RAND_IR         2836
#define RAND_MASK 123459876

    if (iPtr->randSeed == 0) {
      /*
       * Don't allow a 0 seed, since it breaks the generator.  Shift
       * it to some other value.
       */

      iPtr->randSeed = 123459876;
    }
    tmp = iPtr->randSeed/RAND_IQ;
    iPtr->randSeed = RAND_IA*(iPtr->randSeed - tmp*RAND_IQ) - RAND_IR*tmp;
    if (iPtr->randSeed < 0) {
      iPtr->randSeed += RAND_IM;
    }

    /*
     * On 64-bit architectures we need to mask off the upper bits to
     * ensure we only have a 32-bit range.  The constant has the
     * bizarre form below in order to make sure that it doesn't
     * get sign-extended (the rules for sign extension are very
     * concat, particularly on 64-bit machines).
     */

    iPtr->randSeed &= ((((unsigned long) 0xfffffff) << 4) | 0xf);
    dResult = iPtr->randSeed * (1.0/RAND_IM);

    /*
     * Push a Tcl object with the result.
     */

    PUSH_OBJECT(Tcl_NewDoubleObj(dResult));
    
    /*
     * Reflect the change to stackTop back in eePtr.
     */

    DECACHE_STACK_INFO();
    return TCL_OK;
}

static int
ExprRoundFunc(interp, eePtr, clientData)
    Tcl_Interp *interp;       /* The interpreter in which to execute the
                         * function. */
    ExecEnv *eePtr;           /* Points to the environment for executing
                         * the function. */
    ClientData clientData;    /* Ignored. */
{
    StackItem *stackPtr;        /* Cached evaluation stack base pointer. */
    register int stackTop;    /* Cached top index of evaluation stack. */
    Tcl_Obj *valuePtr;
    Tcl_ObjType *tPtr;
    long i = 0;               /* Initialized to avoid compiler warning. */
    long iResult;
    double d, temp;
    int result = TCL_OK;

    /*
     * Set stackPtr and stackTop from eePtr.
     */
    
    CACHE_STACK_INFO();

    /*
     * Pop the argument from the evaluation stack.
     */

    valuePtr = POP_OBJECT();
    tPtr = valuePtr->typePtr;
    
    if (tPtr == &tclIntType) {
      i = valuePtr->internalRep.longValue;
    } else if (tPtr == &tclDoubleType) {
      d = valuePtr->internalRep.doubleValue;
    } else {                  /* FAILS IF STRING REP HAS NULLS */
      char *s = Tcl_GetStringFromObj(valuePtr, (int *) NULL);
      
      if (TclLooksLikeInt(s)) {
          result = Tcl_GetLongFromObj((Tcl_Interp *) NULL, valuePtr, &i);
      } else {
          result = Tcl_GetDoubleFromObj((Tcl_Interp *) NULL, valuePtr, &d);
      }
      if (result != TCL_OK) {
          Tcl_ResetResult(interp);
          Tcl_AppendToObj(Tcl_GetObjResult(interp),
                "argument to math function didn't have numeric value", -1);
          goto done;
      }
      tPtr = valuePtr->typePtr;
    }

    /*
     * Push a Tcl object with the result.
     */
    
    if (tPtr == &tclIntType) {
      iResult = i;
    } else {
      if (d < 0.0) {
          if (d <= (((double) (long) LONG_MIN) - 0.5)) {
            tooLarge:
            Tcl_ResetResult(interp);
            Tcl_AppendToObj(Tcl_GetObjResult(interp),
                    "integer value too large to represent", -1);
            Tcl_SetErrorCode(interp, "ARITH", "IOVERFLOW",
                  "integer value too large to represent",
                  (char *) NULL);
            result = TCL_ERROR;
            goto done;
          }
          temp = (long) (d - 0.5);
      } else {
          if (d >= (((double) LONG_MAX + 0.5))) {
            goto tooLarge;
          }
          temp = (long) (d + 0.5);
      }
      if (IS_NAN(temp) || IS_INF(temp)) {
          TclExprFloatError(interp, temp);
          result = TCL_ERROR;
          goto done;
      }
      iResult = (long) temp;
    }
    PUSH_OBJECT(Tcl_NewLongObj(iResult));

    /*
     * Reflect the change to stackTop back in eePtr.
     */

    done:
    Tcl_DecrRefCount(valuePtr);
    DECACHE_STACK_INFO();
    return result;
}

static int
ExprSrandFunc(interp, eePtr, clientData)
    Tcl_Interp *interp;       /* The interpreter in which to execute the
                         * function. */
    ExecEnv *eePtr;           /* Points to the environment for executing
                         * the function. */
    ClientData clientData;    /* Ignored. */
{
    StackItem *stackPtr;        /* Cached evaluation stack base pointer. */
    register int stackTop;    /* Cached top index of evaluation stack. */
    Interp *iPtr = (Interp *) interp;
    Tcl_Obj *valuePtr;
    Tcl_ObjType *tPtr;
    long i = 0;               /* Initialized to avoid compiler warning. */
    int result;

    /*
     * Set stackPtr and stackTop from eePtr.
     */
    
    CACHE_STACK_INFO();

    /*
     * Pop the argument from the evaluation stack.  Use the value
     * to reset the random number seed.
     */

    valuePtr = POP_OBJECT();
    tPtr = valuePtr->typePtr;
    
    if (tPtr == &tclIntType) {
      i = valuePtr->internalRep.longValue;
    } else {                  /* FAILS IF STRING REP HAS NULLS */
      result = Tcl_GetLongFromObj((Tcl_Interp *) NULL, valuePtr, &i);
      if (result != TCL_OK) {
          Tcl_ResetResult(interp);
          Tcl_AppendStringsToObj(Tcl_GetObjResult(interp), "can't use ",
                ((tPtr == &tclDoubleType)? "floating-point value" : "non-numeric string"),
                " as argument to srand", (char *) NULL);
          Tcl_DecrRefCount(valuePtr);
          DECACHE_STACK_INFO();
          return result;
      }
    }
    
    /*
     * Reset the seed.
     */

    iPtr->flags |= RAND_SEED_INITIALIZED;
    iPtr->randSeed = i;

    /*
     * To avoid duplicating the random number generation code we simply
     * clean up our state and call the real random number function. That
     * function will always succeed.
     */
    
    Tcl_DecrRefCount(valuePtr);
    DECACHE_STACK_INFO();

    ExprRandFunc(interp, eePtr, clientData);
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * ExprCallMathFunc --
 *
 *    This procedure is invoked to call a non-builtin math function
 *    during the execution of an expression. 
 *
 * Results:
 *    TCL_OK is returned if all went well and the function's value
 *    was computed successfully. If an error occurred, TCL_ERROR
 *    is returned and an error message is left in the interpreter's
 *    result.     After a successful return this procedure pushes a Tcl object
 *    holding the result. 
 *
 * Side effects:
 *    None, unless the called math function has side effects.
 *
 *----------------------------------------------------------------------
 */

static int
ExprCallMathFunc(interp, eePtr, objc, objv)
    Tcl_Interp *interp;       /* The interpreter in which to execute the
                         * function. */
    ExecEnv *eePtr;           /* Points to the environment for executing
                         * the function. */
    int objc;                 /* Number of arguments. The function name is
                         * the 0-th argument. */
    Tcl_Obj **objv;           /* The array of arguments. The function name
                         * is objv[0]. */
{
    Interp *iPtr = (Interp *) interp;
    StackItem *stackPtr;        /* Cached evaluation stack base pointer. */
    register int stackTop;    /* Cached top index of evaluation stack. */
    char *funcName;
    Tcl_HashEntry *hPtr;
    MathFunc *mathFuncPtr;    /* Information about math function. */
    Tcl_Value args[MAX_MATH_ARGS]; /* Arguments for function call. */
    Tcl_Value funcResult;     /* Result of function call as Tcl_Value. */
    register Tcl_Obj *valuePtr;
    Tcl_ObjType *tPtr;
    long i;
    double d;
    int j, k, result;
    
    Tcl_ResetResult(interp);
    
    /*
     * Set stackPtr and stackTop from eePtr.
     */
    
    CACHE_STACK_INFO();

    /*
     * Look up the MathFunc record for the function.
     * THIS FAILS IF THE OBJECT'S STRING REP CONTAINS NULLS.
     */

    funcName = Tcl_GetStringFromObj(objv[0], (int *) NULL);
    hPtr = Tcl_FindHashEntry(&iPtr->mathFuncTable, funcName);
    if (hPtr == NULL) {
      Tcl_AppendStringsToObj(Tcl_GetObjResult(interp),
            "unknown math function \"", funcName, "\"", (char *) NULL);
      result = TCL_ERROR;
      goto done;
    }
    mathFuncPtr = (MathFunc *) Tcl_GetHashValue(hPtr);
    if (mathFuncPtr->numArgs != (objc-1)) {
      panic("ExprCallMathFunc: expected number of args %d != actual number %d",
              mathFuncPtr->numArgs, objc);
      result = TCL_ERROR;
      goto done;
    }

    /*
     * Collect the arguments for the function, if there are any, into the
     * array "args". Note that args[0] will have the Tcl_Value that
     * corresponds to objv[1].
     */

    for (j = 1, k = 0;  j < objc;  j++, k++) {
      valuePtr = objv[j];
      tPtr = valuePtr->typePtr;
      
      if (tPtr == &tclIntType) {
          i = valuePtr->internalRep.longValue;
      } else if (tPtr == &tclDoubleType) {
          d = valuePtr->internalRep.doubleValue;
      } else {
          /*
           * Try to convert to int first then double.
           * FAILS IF STRING REP HAS NULLS.
           */
          
          char *s = Tcl_GetStringFromObj(valuePtr, (int *) NULL);
          
          if (TclLooksLikeInt(s)) {
            result = Tcl_GetLongFromObj((Tcl_Interp *) NULL, valuePtr, &i);
          } else {
            result = Tcl_GetDoubleFromObj((Tcl_Interp *) NULL,
                  valuePtr, &d);
          }
          if (result != TCL_OK) {
            Tcl_AppendToObj(Tcl_GetObjResult(interp),
                  "argument to math function didn't have numeric value", -1);
            goto done;
          }
          tPtr = valuePtr->typePtr;
      }

      /*
       * Copy the object's numeric value to the argument record,
       * converting it if necessary. 
       */
      
      if (tPtr == &tclIntType) {
          if (mathFuncPtr->argTypes[k] == TCL_DOUBLE) {
            args[k].type = TCL_DOUBLE;
            args[k].doubleValue = i;
          } else {
            args[k].type = TCL_INT;
            args[k].intValue = i;
          }
      } else {
          if (mathFuncPtr->argTypes[k] == TCL_INT) {
            args[k].type = TCL_INT;
            args[k].intValue = (long) d;
          } else {
            args[k].type = TCL_DOUBLE;
            args[k].doubleValue = d;
          }
      }
    }

    /*
     * Invoke the function and copy its result back into valuePtr.
     */

    tcl_MathInProgress++;
    result = (*mathFuncPtr->proc)(mathFuncPtr->clientData, interp, args,
          &funcResult);
    tcl_MathInProgress--;
    if (result != TCL_OK) {
      goto done;
    }

    /*
     * Pop the objc top stack elements and decrement their ref counts.
     */
            
    i = (stackTop - (objc-1));
    while (i <= stackTop) {
      valuePtr = stackPtr[i].o;
      Tcl_DecrRefCount(valuePtr);
      i++;
    }
    stackTop -= objc;
    
    /*
     * Push the call's object result.
     */
    
    if (funcResult.type == TCL_INT) {
      PUSH_OBJECT(Tcl_NewLongObj(funcResult.intValue));
    } else {
      d = funcResult.doubleValue;
      if (IS_NAN(d) || IS_INF(d)) {
          TclExprFloatError(interp, d);
          result = TCL_ERROR;
          goto done;
      }
      PUSH_OBJECT(Tcl_NewDoubleObj(d));
    }

    /*
     * Reflect the change to stackTop back in eePtr.
     */

    done:
    DECACHE_STACK_INFO();
    return result;
}

/*
 *----------------------------------------------------------------------
 *
 * 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(interp, value)
    Tcl_Interp *interp;       /* Where to store error message. */
    double value;       /* Value returned after error;  used to
                         * distinguish underflows from overflows. */
{
    char *s;

    Tcl_ResetResult(interp);
    if ((errno == EDOM) || (value != value)) {
      s = "domain error: argument not in valid range";
      Tcl_AppendToObj(Tcl_GetObjResult(interp), s, -1);
      Tcl_SetErrorCode(interp, "ARITH", "DOMAIN", s, (char *) NULL);
    } else if ((errno == ERANGE) || IS_INF(value)) {
      if (value == 0.0) {
          s = "floating-point value too small to represent";
          Tcl_AppendToObj(Tcl_GetObjResult(interp), s, -1);
          Tcl_SetErrorCode(interp, "ARITH", "UNDERFLOW", s, (char *) NULL);
      } else {
          s = "floating-point value too large to represent";
          Tcl_AppendToObj(Tcl_GetObjResult(interp), s, -1);
          Tcl_SetErrorCode(interp, "ARITH", "OVERFLOW", s, (char *) NULL);
      }
    } else {                  /* FAILS IF STRING REP CONTAINS NULLS */
      char msg[100];
      
      sprintf(msg, "unknown floating-point error, errno = %d", errno);
      Tcl_AppendToObj(Tcl_GetObjResult(interp), msg, -1);
      Tcl_SetErrorCode(interp, "ARITH", "UNKNOWN", msg, (char *) NULL);
    }
}

#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(value)
    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(unused, interp, argc, argv)
    ClientData unused;        /* Unused. */
    Tcl_Interp *interp;       /* The current interpreter. */
    int argc;                 /* The number of arguments. */
    char **argv;        /* The argument strings. */
{
    register double total = 0.0;
    register int i;
    int maxSizeDecade = 0;
    double totalHeaderBytes = (tclNumCompilations * sizeof(ByteCode));

    for (i = 0;  i < 256;  i++) {
        if (instructionCount[i] != 0) {
            total += instructionCount[i];
        }
    }

    for (i = 31;  i >= 0;  i--) {
        if ((tclSourceCount[i] > 0) && (tclByteCodeCount[i] > 0)) {
            maxSizeDecade = i;
          break;
        }
    } 

    fprintf(stdout, "\nNumber of compilations         %ld\n",
          tclNumCompilations);
    fprintf(stdout, "Number of executions       %ld\n",
          numExecutions);
    fprintf(stdout, "Average executions/compilation   %.0f\n",
          ((float) numExecutions/tclNumCompilations));
    
    fprintf(stdout, "\nInstructions executed          %.0f\n",
          total);
    fprintf(stdout, "Average instructions/compile     %.0f\n",
          total/tclNumCompilations);
    fprintf(stdout, "Average instructions/execution   %.0f\n",
          total/numExecutions);
    
    fprintf(stdout, "\nTotal source bytes       %.6g\n",
          tclTotalSourceBytes);
    fprintf(stdout, "Total code bytes           %.6g\n",
          tclTotalCodeBytes);
    fprintf(stdout, "Average code/compilation   %.0f\n",
          tclTotalCodeBytes/tclNumCompilations);
    fprintf(stdout, "Average code/source        %.2f\n",
          tclTotalCodeBytes/tclTotalSourceBytes);
    fprintf(stdout, "Current source bytes       %.6g\n",
          tclCurrentSourceBytes);
    fprintf(stdout, "Current code bytes         %.6g\n",
          tclCurrentCodeBytes);
    fprintf(stdout, "Current code/source        %.2f\n",
          tclCurrentCodeBytes/tclCurrentSourceBytes);
    
    fprintf(stdout, "\nTotal objects allocated        %ld\n",
          tclObjsAlloced);
    fprintf(stdout, "Total objects freed        %ld\n",
          tclObjsFreed);
    fprintf(stdout, "Current objects:           %ld\n",
          (tclObjsAlloced - tclObjsFreed));

    fprintf(stdout, "\nBreakdown of code byte requirements:\n");
    fprintf(stdout, "                   Total bytes      Pct of    Avg per\n");
    fprintf(stdout, "                                  all code    compile\n");
    fprintf(stdout, "Total code        %12.6g        100%%   %8.2f\n",
          tclTotalCodeBytes, tclTotalCodeBytes/tclNumCompilations);
    fprintf(stdout, "Header            %12.6g   %8.2f%%   %8.2f\n",
          totalHeaderBytes,
          ((totalHeaderBytes * 100.0) / tclTotalCodeBytes),
          totalHeaderBytes/tclNumCompilations);
    fprintf(stdout, "Instructions      %12.6g   %8.2f%%   %8.2f\n",
          tclTotalInstBytes,
          ((tclTotalInstBytes * 100.0) / tclTotalCodeBytes),
          tclTotalInstBytes/tclNumCompilations);
    fprintf(stdout, "Objects           %12.6g   %8.2f%%   %8.2f\n",
          tclTotalObjBytes,
          ((tclTotalObjBytes * 100.0) / tclTotalCodeBytes),
          tclTotalObjBytes/tclNumCompilations);
    fprintf(stdout, "Exception table   %12.6g   %8.2f%%   %8.2f\n",
          tclTotalExceptBytes,
          ((tclTotalExceptBytes * 100.0) / tclTotalCodeBytes),
          tclTotalExceptBytes/tclNumCompilations);
    fprintf(stdout, "Auxiliary data    %12.6g   %8.2f%%   %8.2f\n",
          tclTotalAuxBytes,
          ((tclTotalAuxBytes * 100.0) / tclTotalCodeBytes),
          tclTotalAuxBytes/tclNumCompilations);
    fprintf(stdout, "Command map       %12.6g   %8.2f%%   %8.2f\n",
          tclTotalCmdMapBytes,
          ((tclTotalCmdMapBytes * 100.0) / tclTotalCodeBytes),
          tclTotalCmdMapBytes/tclNumCompilations);
    
    fprintf(stdout, "\nSource and ByteCode size distributions:\n");
    fprintf(stdout, "    binary decade          source        code\n");
    for (i = 0;  i <= maxSizeDecade;  i++) {
      int decadeLow, decadeHigh;

      if (i == 0) {
          decadeLow = 0;
      } else {
          decadeLow = 1 << i;
      }
      decadeHigh = (1 << (i+1)) - 1;
        fprintf(stdout, "     %6d -%6d          %6d   %6d\n",
            decadeLow, decadeHigh,
            tclSourceCount[i], tclByteCodeCount[i]);
    }

    fprintf(stdout, "\nInstruction counts:\n");
    for (i = 0;  i < 256;  i++) {
        if (instructionCount[i]) {
            fprintf(stdout, "%20s %8d %6.2f%%\n",
                opName[i], instructionCount[i],
                (instructionCount[i] * 100.0)/total);
        }
    }

#ifdef TCL_MEM_DEBUG
    fprintf(stdout, "\nHeap Statistics:\n");
    TclDumpMemoryInfo(stdout);
#endif /* TCL_MEM_DEBUG */

    return TCL_OK;
}
#endif /* TCL_COMPILE_STATS */

/*
 *----------------------------------------------------------------------
 *
 * Tcl_GetCommandFromObj --
 *
 *      Returns the command specified by the name in a Tcl_Obj.
 *
 * Results:
 *    Returns a token for the command if it is found. Otherwise, if it
 *    can't be found or there is an error, returns NULL.
 *
 * Side effects:
 *      May update the internal representation for the object, caching
 *      the command reference so that the next time this procedure is
 *    called with the same object, the command can be found quickly.
 *
 *----------------------------------------------------------------------
 */

Tcl_Command
Tcl_GetCommandFromObj(interp, objPtr)
    Tcl_Interp *interp;       /* The interpreter in which to resolve the
                         * command and to report errors. */
    register Tcl_Obj *objPtr; /* The object containing the command's
                         * name. If the name starts with "::", will
                         * be looked up in global namespace. Else,
                         * looked up first in the current namespace
                         * if contextNsPtr is NULL, then in global
                         * namespace. */
{
    Interp *iPtr = (Interp *) interp;
    register ResolvedCmdName *resPtr;
    register Command *cmdPtr;
    Namespace *currNsPtr;
    int result;

    /*
     * Get the internal representation, converting to a command type if
     * needed. The internal representation is a ResolvedCmdName that points
     * to the actual command.
     */
    
    if (objPtr->typePtr != &tclCmdNameType) {
        result = tclCmdNameType.setFromAnyProc(interp, objPtr);
        if (result != TCL_OK) {
            return (Tcl_Command) NULL;
        }
    }
    resPtr = (ResolvedCmdName *) objPtr->internalRep.otherValuePtr;

    /*
     * Get the current namespace.
     */
    
    if (iPtr->varFramePtr != NULL) {
      currNsPtr = iPtr->varFramePtr->nsPtr;
    } else {
      currNsPtr = iPtr->globalNsPtr;
    }

    /*
     * Check the context namespace and the namespace epoch of the resolved
     * symbol to make sure that it is fresh. If not, then force another
     * conversion to the command type, to discard the old rep and create a
     * new one. Note that we verify that the namespace id of the context
     * namespace is the same as the one we cached; this insures that the
     * namespace wasn't deleted and a new one created at the same address
     * with the same command epoch.
     */
    
    cmdPtr = NULL;
    if ((resPtr != NULL)
          && (resPtr->refNsPtr == currNsPtr)
          && (resPtr->refNsId == currNsPtr->nsId)
          && (resPtr->refNsCmdEpoch == currNsPtr->cmdRefEpoch)) {
        cmdPtr = resPtr->cmdPtr;
        if (cmdPtr->cmdEpoch != resPtr->cmdEpoch) {
            cmdPtr = NULL;
        }
    }

    if (cmdPtr == NULL) {
        result = tclCmdNameType.setFromAnyProc(interp, objPtr);
        if (result != TCL_OK) {
            return (Tcl_Command) NULL;
        }
        resPtr = (ResolvedCmdName *) objPtr->internalRep.otherValuePtr;
        if (resPtr != NULL) {
            cmdPtr = resPtr->cmdPtr;
        }
    }

    if (cmdPtr == NULL) {
      return (Tcl_Command) NULL;
    }
    return (Tcl_Command) cmdPtr;
}

/*
 *----------------------------------------------------------------------
 *
 * FreeCmdNameInternalRep --
 *
 *    Frees the resources associated with a cmdName object's internal
 *    representation.
 *
 * Results:
 *    None.
 *
 * Side effects:
 *    Decrements the ref count of any cached ResolvedCmdName structure
 *    pointed to by the cmdName's internal representation. If this is 
 *    the last use of the ResolvedCmdName, it is freed. This in turn
 *    decrements the ref count of the Command structure pointed to by 
 *    the ResolvedSymbol, which may free the Command structure.
 *
 *----------------------------------------------------------------------
 */

static void
FreeCmdNameInternalRep(objPtr)
    register Tcl_Obj *objPtr; /* CmdName object with internal
                         * representation to free. */
{
    register ResolvedCmdName *resPtr =
      (ResolvedCmdName *) objPtr->internalRep.otherValuePtr;

    if (resPtr != NULL) {
      /*
       * Decrement the reference count of the ResolvedCmdName structure.
       * If there are no more uses, free the ResolvedCmdName structure.
       */
    
        resPtr->refCount--;
        if (resPtr->refCount == 0) {
            /*
           * Now free the cached command, unless it is still in its
             * hash table or if there are other references to it
             * from other cmdName objects.
           */
          
            Command *cmdPtr = resPtr->cmdPtr;
            TclCleanupCommand(cmdPtr);
            ckfree((char *) resPtr);
        }
    }
}

/*
 *----------------------------------------------------------------------
 *
 * DupCmdNameInternalRep --
 *
 *    Initialize the internal representation of an cmdName Tcl_Obj to a
 *    copy of the internal representation of an existing cmdName object. 
 *
 * Results:
 *    None.
 *
 * Side effects:
 *    "copyPtr"s internal rep is set to point to the ResolvedCmdName
 *    structure corresponding to "srcPtr"s internal rep. Increments the
 *    ref count of the ResolvedCmdName structure pointed to by the
 *    cmdName's internal representation.
 *
 *----------------------------------------------------------------------
 */

static void
DupCmdNameInternalRep(srcPtr, copyPtr)
    Tcl_Obj *srcPtr;          /* Object with internal rep to copy. */
    register Tcl_Obj *copyPtr;      /* Object with internal rep to set. */
{
    register ResolvedCmdName *resPtr =
        (ResolvedCmdName *) srcPtr->internalRep.otherValuePtr;

    copyPtr->internalRep.twoPtrValue.ptr1 = (VOID *) resPtr;
    copyPtr->internalRep.twoPtrValue.ptr2 = NULL;
    if (resPtr != NULL) {
        resPtr->refCount++;
    }
    copyPtr->typePtr = &tclCmdNameType;
}

/*
 *----------------------------------------------------------------------
 *
 * SetCmdNameFromAny --
 *
 *    Generate an cmdName internal form for the Tcl object "objPtr".
 *
 * Results:
 *    The return value is a standard Tcl result. The conversion always
 *    succeeds and TCL_OK is returned.
 *
 * Side effects:
 *    A pointer to a ResolvedCmdName structure that holds a cached pointer
 *    to the command with a name that matches objPtr's string rep is
 *    stored as objPtr's internal representation. This ResolvedCmdName
 *    pointer will be NULL if no matching command was found. The ref count
 *    of the cached Command's structure (if any) is also incremented.
 *
 *----------------------------------------------------------------------
 */

static int
SetCmdNameFromAny(interp, objPtr)
    Tcl_Interp *interp;       /* Used for error reporting if not NULL. */
    register Tcl_Obj *objPtr; /* The object to convert. */
{
    Interp *iPtr = (Interp *) interp;
    char *name;
    Tcl_Command cmd;
    register Command *cmdPtr;
    Namespace *currNsPtr;
    register ResolvedCmdName *resPtr;

    /*
     * Get "objPtr"s string representation. Make it up-to-date if necessary.
     */

    name = objPtr->bytes;
    if (name == NULL) {
      name = Tcl_GetStringFromObj(objPtr, (int *) NULL);
    }

    /*
     * Find the Command structure, if any, that describes the command called
     * "name". Build a ResolvedCmdName that holds a cached pointer to this
     * Command, and bump the reference count in the referenced Command
     * structure. A Command structure will not be deleted as long as it is
     * referenced from a CmdName object.
     */

    cmd = Tcl_FindCommand(interp, name, (Tcl_Namespace *) NULL,
          /*flags*/ 0);
    cmdPtr = (Command *) cmd;
    if (cmdPtr != NULL) {
      /*
       * Get the current namespace.
       */
      
      if (iPtr->varFramePtr != NULL) {
          currNsPtr = iPtr->varFramePtr->nsPtr;
      } else {
          currNsPtr = iPtr->globalNsPtr;
      }
      
      cmdPtr->refCount++;
        resPtr = (ResolvedCmdName *) ckalloc(sizeof(ResolvedCmdName));
        resPtr->cmdPtr        = cmdPtr;
        resPtr->refNsPtr      = currNsPtr;
        resPtr->refNsId       = currNsPtr->nsId;
        resPtr->refNsCmdEpoch = currNsPtr->cmdRefEpoch;
        resPtr->cmdEpoch      = cmdPtr->cmdEpoch;
        resPtr->refCount      = 1;
    } else {
      resPtr = NULL;    /* no command named "name" was found */
    }

    /*
     * Free the old internalRep before setting the new one. We do this as
     * late as possible to allow the conversion code, in particular
     * GetStringFromObj, to use that old internalRep. If no Command
     * structure was found, leave NULL as the cached value.
     */

    if ((objPtr->typePtr != NULL)
          && (objPtr->typePtr->freeIntRepProc != NULL)) {
      objPtr->typePtr->freeIntRepProc(objPtr);
    }
    
    objPtr->internalRep.twoPtrValue.ptr1 = (VOID *) resPtr;
    objPtr->internalRep.twoPtrValue.ptr2 = NULL;
    objPtr->typePtr = &tclCmdNameType;
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * UpdateStringOfCmdName --
 *
 *    Update the string representation for an cmdName object.
 *
 * Results:
 *    None.
 *
 * Side effects:
 *    Generates a panic. 
 *
 *----------------------------------------------------------------------
 */

static void
UpdateStringOfCmdName(objPtr)
    Tcl_Obj *objPtr;          /* CmdName obj to update string rep. */
{
    /*
     * This procedure is never invoked since the internal representation of
     * a cmdName object is never modified.
     */

    panic("UpdateStringOfCmdName should never be invoked");
}

#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 char *
StringForResultCode(result)
    int result;               /* The Tcl result code for which to
                         * generate a string. */
{
    static char buf[20];
    
    if ((result >= TCL_OK) && (result <= TCL_CONTINUE)) {
      return resultStrings[result];
    }
    TclFormatInt(buf, result);
    return buf;
}
#endif /* TCL_COMPILE_DEBUG */

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