text: /*
  ** $Id: lvm.c $
  ** Lua virtual machine
  ** See Copyright Notice in lua.h
  */
  
  #define lvm_c
  #define LUA_CORE
  
  #include "lprefix.h"
  
  #include <float.h>
  #include <limits.h>
  #include <math.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  
  #include "lua.h"
  
  #include "ldebug.h"
  #include "ldo.h"
  #include "lfunc.h"
  #include "lgc.h"
  #include "lobject.h"
  #include "lopcodes.h"
  #include "lstate.h"
  #include "lstring.h"
  #include "ltable.h"
  #include "ltm.h"
  #include "lvm.h"
  
  
  /*
  ** By default, use jump tables in the main interpreter loop on gcc
  ** and compatible compilers.
  */
  #if !defined(LUA_USE_JUMPTABLE)
  #if defined(__GNUC__)
  #define LUA_USE_JUMPTABLE	1
  #else
  #define LUA_USE_JUMPTABLE	0
  #endif
  #endif
  
  
  
  /* limit for table tag-method chains (to avoid infinite loops) */
  #define MAXTAGLOOP	2000
  
  
  /*
  ** 'l_intfitsf' checks whether a given integer is in the range that
  ** can be converted to a float without rounding. Used in comparisons.
  */
  
  /* number of bits in the mantissa of a float */
  #define NBM		(l_floatatt(MANT_DIG))
  
  /*
  ** Check whether some integers may not fit in a float, testing whether
  ** (maxinteger >> NBM) > 0. (That implies (1 << NBM) <= maxinteger.)
  ** (The shifts are done in parts, to avoid shifting by more than the size
  ** of an integer. In a worst case, NBM == 113 for long double and
  ** sizeof(long) == 32.)
  */
  #if ((((LUA_MAXINTEGER >> (NBM / 4)) >> (NBM / 4)) >> (NBM / 4)) \
  	>> (NBM - (3 * (NBM / 4))))  >  0
  
  /* limit for integers that fit in a float */
  #define MAXINTFITSF	((lua_Unsigned)1 << NBM)
  
  /* check whether 'i' is in the interval [-MAXINTFITSF, MAXINTFITSF] */
  #define l_intfitsf(i)	((MAXINTFITSF + l_castS2U(i)) <= (2 * MAXINTFITSF))
  
  #else  /* all integers fit in a float precisely */
  
  #define l_intfitsf(i)	1
  
  #endif
  
  
  /*
  ** Try to convert a value from string to a number value.
  ** If the value is not a string or is a string not representing
  ** a valid numeral (or if coercions from strings to numbers
  ** are disabled via macro 'cvt2num'), do not modify 'result'
  ** and return 0.
  */
  static int l_strton (const TValue *obj, TValue *result) {
    lua_assert(obj != result);
    if (!cvt2num(obj))  /* is object not a string? */
      return 0;
    else
      return (luaO_str2num(svalue(obj), result) == vslen(obj) + 1);
  }
  
  
  /*
  ** Try to convert a value to a float. The float case is already handled
  ** by the macro 'tonumber'.
  */
  int luaV_tonumber_ (const TValue *obj, lua_Number *n) {
    TValue v;
    if (ttisinteger(obj)) {
      *n = cast_num(ivalue(obj));
      return 1;
    }
    else if (l_strton(obj, &v)) {  /* string coercible to number? */
      *n = nvalue(&v);  /* convert result of 'luaO_str2num' to a float */
      return 1;
    }
    else
      return 0;  /* conversion failed */
  }
  
  
  /*
  ** try to convert a float to an integer, rounding according to 'mode'.
  */
  int luaV_flttointeger (lua_Number n, lua_Integer *p, F2Imod mode) {
    lua_Number f = l_floor(n);
    if (n != f) {  /* not an integral value? */
      if (mode == F2Ieq) return 0;  /* fails if mode demands integral value */
      else if (mode == F2Iceil)  /* needs ceil? */
        f += 1;  /* convert floor to ceil (remember: n != f) */
    }
    return lua_numbertointeger(f, p);
  }
  
  
  /*
  ** try to convert a value to an integer, rounding according to 'mode',
  ** without string coercion.
  ** ("Fast track" handled by macro 'tointegerns'.)
  */
  int luaV_tointegerns (const TValue *obj, lua_Integer *p, F2Imod mode) {
    if (ttisfloat(obj))
      return luaV_flttointeger(fltvalue(obj), p, mode);
    else if (ttisinteger(obj)) {
      *p = ivalue(obj);
      return 1;
    }
    else
      return 0;
  }
  
  
  /*
  ** try to convert a value to an integer.
  */
  int luaV_tointeger (const TValue *obj, lua_Integer *p, F2Imod mode) {
    TValue v;
    if (l_strton(obj, &v))  /* does 'obj' point to a numerical string? */
      obj = &v;  /* change it to point to its corresponding number */
    return luaV_tointegerns(obj, p, mode);
  }
  
  
  /*
  ** Try to convert a 'for' limit to an integer, preserving the semantics
  ** of the loop. Return true if the loop must not run; otherwise, '*p'
  ** gets the integer limit.
  ** (The following explanation assumes a positive step; it is valid for
  ** negative steps mutatis mutandis.)
  ** If the limit is an integer or can be converted to an integer,
  ** rounding down, that is the limit.
  ** Otherwise, check whether the limit can be converted to a float. If
  ** the float is too large, clip it to LUA_MAXINTEGER.  If the float
  ** is too negative, the loop should not run, because any initial
  ** integer value is greater than such limit; so, the function returns
  ** true to signal that. (For this latter case, no integer limit would be
  ** correct; even a limit of LUA_MININTEGER would run the loop once for
  ** an initial value equal to LUA_MININTEGER.)
  */
  static int forlimit (lua_State *L, lua_Integer init, const TValue *lim,
                                     lua_Integer *p, lua_Integer step) {
    if (!luaV_tointeger(lim, p, (step < 0 ? F2Iceil : F2Ifloor))) {
      /* not coercible to in integer */
      lua_Number flim;  /* try to convert to float */
      if (!tonumber(lim, &flim)) /* cannot convert to float? */
        luaG_forerror(L, lim, "limit");
      /* else 'flim' is a float out of integer bounds */
      if (luai_numlt(0, flim)) {  /* if it is positive, it is too large */
        if (step < 0) return 1;  /* initial value must be less than it */
        *p = LUA_MAXINTEGER;  /* truncate */
      }
      else {  /* it is less than min integer */
        if (step > 0) return 1;  /* initial value must be greater than it */
        *p = LUA_MININTEGER;  /* truncate */
      }
    }
    return (step > 0 ? init > *p : init < *p);  /* not to run? */
  }
  
  
  /*
  ** Prepare a numerical for loop (opcode OP_FORPREP).
  ** Return true to skip the loop. Otherwise,
  ** after preparation, stack will be as follows:
  **   ra : internal index (safe copy of the control variable)
  **   ra + 1 : loop counter (integer loops) or limit (float loops)
  **   ra + 2 : step
  **   ra + 3 : control variable
  */
  static int forprep (lua_State *L, StkId ra) {
    TValue *pinit = s2v(ra);
    TValue *plimit = s2v(ra + 1);
    TValue *pstep = s2v(ra + 2);
    if (ttisinteger(pinit) && ttisinteger(pstep)) { /* integer loop? */
      lua_Integer init = ivalue(pinit);
      lua_Integer step = ivalue(pstep);
      lua_Integer limit;
      if (step == 0)
        luaG_runerror(L, "'for' step is zero");
      setivalue(s2v(ra + 3), init);  /* control variable */
      if (forlimit(L, init, plimit, &limit, step))
        return 1;  /* skip the loop */
      else {  /* prepare loop counter */
        lua_Unsigned count;
        if (step > 0) {  /* ascending loop? */
          count = l_castS2U(limit) - l_castS2U(init);
          if (step != 1)  /* avoid division in the too common case */
            count /= l_castS2U(step);
        }
        else {  /* step < 0; descending loop */
          count = l_castS2U(init) - l_castS2U(limit);
          /* 'step+1' avoids negating 'mininteger' */
          count /= l_castS2U(-(step + 1)) + 1u;
        }
        /* store the counter in place of the limit (which won't be
           needed anymore */
        setivalue(plimit, l_castU2S(count));
      }
    }
    else {  /* try making all values floats */
      lua_Number init; lua_Number limit; lua_Number step;
      if (unlikely(!tonumber(plimit, &limit)))
        luaG_forerror(L, plimit, "limit");
      if (unlikely(!tonumber(pstep, &step)))
        luaG_forerror(L, pstep, "step");
      if (unlikely(!tonumber(pinit, &init)))
        luaG_forerror(L, pinit, "initial value");
      if (step == 0)
        luaG_runerror(L, "'for' step is zero");
      if (luai_numlt(0, step) ? luai_numlt(limit, init)
                              : luai_numlt(init, limit))
        return 1;  /* skip the loop */
      else {
        /* make sure internal values are all floats */
        setfltvalue(plimit, limit);
        setfltvalue(pstep, step);
        setfltvalue(s2v(ra), init);  /* internal index */
        setfltvalue(s2v(ra + 3), init);  /* control variable */
      }
    }
    return 0;
  }
  
  
  /*
  ** Execute a step of a float numerical for loop, returning
  ** true iff the loop must continue. (The integer case is
  ** written online with opcode OP_FORLOOP, for performance.)
  */
  static int floatforloop (StkId ra) {
    lua_Number step = fltvalue(s2v(ra + 2));
    lua_Number limit = fltvalue(s2v(ra + 1));
    lua_Number idx = fltvalue(s2v(ra));  /* internal index */
    idx = luai_numadd(L, idx, step);  /* increment index */
    if (luai_numlt(0, step) ? luai_numle(idx, limit)
                            : luai_numle(limit, idx)) {
      chgfltvalue(s2v(ra), idx);  /* update internal index */
      setfltvalue(s2v(ra + 3), idx);  /* and control variable */
      return 1;  /* jump back */
    }
    else
      return 0;  /* finish the loop */
  }
  
  
  /*
  ** Finish the table access 'val = t[key]'.
  ** if 'slot' is NULL, 't' is not a table; otherwise, 'slot' points to
  ** t[k] entry (which must be empty).
  */
  void luaV_finishget (lua_State *L, const TValue *t, TValue *key, StkId val,
                        const TValue *slot) {
    int loop;  /* counter to avoid infinite loops */
    const TValue *tm;  /* metamethod */
    for (loop = 0; loop < MAXTAGLOOP; loop++) {
      if (slot == NULL) {  /* 't' is not a table? */
        lua_assert(!ttistable(t));
        tm = luaT_gettmbyobj(L, t, TM_INDEX);
        if (unlikely(notm(tm)))
          luaG_typeerror(L, t, "index");  /* no metamethod */
        /* else will try the metamethod */
      }
      else {  /* 't' is a table */
        lua_assert(isempty(slot));
        tm = fasttm(L, hvalue(t)->metatable, TM_INDEX);  /* table's metamethod */
        if (tm == NULL) {  /* no metamethod? */
          setnilvalue(s2v(val));  /* result is nil */
          return;
        }
        /* else will try the metamethod */
      }
      if (ttisfunction(tm)) {  /* is metamethod a function? */
        luaT_callTMres(L, tm, t, key, val);  /* call it */
        return;
      }
      t = tm;  /* else try to access 'tm[key]' */
      if (luaV_fastget(L, t, key, slot, luaH_get)) {  /* fast track? */
        setobj2s(L, val, slot);  /* done */
        return;
      }
      /* else repeat (tail call 'luaV_finishget') */
    }
    luaG_runerror(L, "'__index' chain too long; possible loop");
  }
  
  
  /*
  ** Finish a table assignment 't[key] = val'.
  ** If 'slot' is NULL, 't' is not a table.  Otherwise, 'slot' points
  ** to the entry 't[key]', or to a value with an absent key if there
  ** is no such entry.  (The value at 'slot' must be empty, otherwise
  ** 'luaV_fastget' would have done the job.)
  */
  void luaV_finishset (lua_State *L, const TValue *t, TValue *key,
                       TValue *val, const TValue *slot) {
    int loop;  /* counter to avoid infinite loops */
    for (loop = 0; loop < MAXTAGLOOP; loop++) {
      const TValue *tm;  /* '__newindex' metamethod */
      if (slot != NULL) {  /* is 't' a table? */
        Table *h = hvalue(t);  /* save 't' table */
        lua_assert(isempty(slot));  /* slot must be empty */
        tm = fasttm(L, h->metatable, TM_NEWINDEX);  /* get metamethod */
        if (tm == NULL) {  /* no metamethod? */
          if (isabstkey(slot))  /* no previous entry? */
            slot = luaH_newkey(L, h, key);  /* create one */
          /* no metamethod and (now) there is an entry with given key */
          setobj2t(L, cast(TValue *, slot), val);  /* set its new value */
          invalidateTMcache(h);
          luaC_barrierback(L, obj2gco(h), val);
          return;
        }
        /* else will try the metamethod */
      }
      else {  /* not a table; check metamethod */
        tm = luaT_gettmbyobj(L, t, TM_NEWINDEX);
        if (unlikely(notm(tm)))
          luaG_typeerror(L, t, "index");
      }
      /* try the metamethod */
      if (ttisfunction(tm)) {
        luaT_callTM(L, tm, t, key, val);
        return;
      }
      t = tm;  /* else repeat assignment over 'tm' */
      if (luaV_fastget(L, t, key, slot, luaH_get)) {
        luaV_finishfastset(L, t, slot, val);
        return;  /* done */
      }
      /* else 'return luaV_finishset(L, t, key, val, slot)' (loop) */
    }
    luaG_runerror(L, "'__newindex' chain too long; possible loop");
  }
  
  
  /*
  ** Compare two strings 'ls' x 'rs', returning an integer less-equal-
  ** -greater than zero if 'ls' is less-equal-greater than 'rs'.
  ** The code is a little tricky because it allows '\0' in the strings
  ** and it uses 'strcoll' (to respect locales) for each segments
  ** of the strings.
  */
  static int l_strcmp (const TString *ls, const TString *rs) {
    const char *l = getstr(ls);
    size_t ll = tsslen(ls);
    const char *r = getstr(rs);
    size_t lr = tsslen(rs);
    for (;;) {  /* for each segment */
      int temp = strcoll(l, r);
      if (temp != 0)  /* not equal? */
        return temp;  /* done */
      else {  /* strings are equal up to a '\0' */
        size_t len = strlen(l);  /* index of first '\0' in both strings */
        if (len == lr)  /* 'rs' is finished? */
          return (len == ll) ? 0 : 1;  /* check 'ls' */
        else if (len == ll)  /* 'ls' is finished? */
          return -1;  /* 'ls' is less than 'rs' ('rs' is not finished) */
        /* both strings longer than 'len'; go on comparing after the '\0' */
        len++;
        l += len; ll -= len; r += len; lr -= len;
      }
    }
  }
  
  
  /*
  ** Check whether integer 'i' is less than float 'f'. If 'i' has an
  ** exact representation as a float ('l_intfitsf'), compare numbers as
  ** floats. Otherwise, use the equivalence 'i < f <=> i < ceil(f)'.
  ** If 'ceil(f)' is out of integer range, either 'f' is greater than
  ** all integers or less than all integers.
  ** (The test with 'l_intfitsf' is only for performance; the else
  ** case is correct for all values, but it is slow due to the conversion
  ** from float to int.)
  ** When 'f' is NaN, comparisons must result in false.
  */
  static int LTintfloat (lua_Integer i, lua_Number f) {
    if (l_intfitsf(i))
      return luai_numlt(cast_num(i), f);  /* compare them as floats */
    else {  /* i < f <=> i < ceil(f) */
      lua_Integer fi;
      if (luaV_flttointeger(f, &fi, F2Iceil))  /* fi = ceil(f) */
        return i < fi;   /* compare them as integers */
      else  /* 'f' is either greater or less than all integers */
        return f > 0;  /* greater? */
    }
  }
  
  
  /*
  ** Check whether integer 'i' is less than or equal to float 'f'.
  ** See comments on previous function.
  */
  static int LEintfloat (lua_Integer i, lua_Number f) {
    if (l_intfitsf(i))
      return luai_numle(cast_num(i), f);  /* compare them as floats */
    else {  /* i <= f <=> i <= floor(f) */
      lua_Integer fi;
      if (luaV_flttointeger(f, &fi, F2Ifloor))  /* fi = floor(f) */
        return i <= fi;   /* compare them as integers */
      else  /* 'f' is either greater or less than all integers */
        return f > 0;  /* greater? */
    }
  }
  
  
  /*
  ** Check whether float 'f' is less than integer 'i'.
  ** See comments on previous function.
  */
  static int LTfloatint (lua_Number f, lua_Integer i) {
    if (l_intfitsf(i))
      return luai_numlt(f, cast_num(i));  /* compare them as floats */
    else {  /* f < i <=> floor(f) < i */
      lua_Integer fi;
      if (luaV_flttointeger(f, &fi, F2Ifloor))  /* fi = floor(f) */
        return fi < i;   /* compare them as integers */
      else  /* 'f' is either greater or less than all integers */
        return f < 0;  /* less? */
    }
  }
  
  
  /*
  ** Check whether float 'f' is less than or equal to integer 'i'.
  ** See comments on previous function.
  */
  static int LEfloatint (lua_Number f, lua_Integer i) {
    if (l_intfitsf(i))
      return luai_numle(f, cast_num(i));  /* compare them as floats */
    else {  /* f <= i <=> ceil(f) <= i */
      lua_Integer fi;
      if (luaV_flttointeger(f, &fi, F2Iceil))  /* fi = ceil(f) */
        return fi <= i;   /* compare them as integers */
      else  /* 'f' is either greater or less than all integers */
        return f < 0;  /* less? */
    }
  }
  
  
  /*
  ** Return 'l < r', for numbers.
  */
  static int LTnum (const TValue *l, const TValue *r) {
    lua_assert(ttisnumber(l) && ttisnumber(r));
    if (ttisinteger(l)) {
      lua_Integer li = ivalue(l);
      if (ttisinteger(r))
        return li < ivalue(r);  /* both are integers */
      else  /* 'l' is int and 'r' is float */
        return LTintfloat(li, fltvalue(r));  /* l < r ? */
    }
    else {
      lua_Number lf = fltvalue(l);  /* 'l' must be float */
      if (ttisfloat(r))
        return luai_numlt(lf, fltvalue(r));  /* both are float */
      else  /* 'l' is float and 'r' is int */
        return LTfloatint(lf, ivalue(r));
    }
  }
  
  
  /*
  ** Return 'l <= r', for numbers.
  */
  static int LEnum (const TValue *l, const TValue *r) {
    lua_assert(ttisnumber(l) && ttisnumber(r));
    if (ttisinteger(l)) {
      lua_Integer li = ivalue(l);
      if (ttisinteger(r))
        return li <= ivalue(r);  /* both are integers */
      else  /* 'l' is int and 'r' is float */
        return LEintfloat(li, fltvalue(r));  /* l <= r ? */
    }
    else {
      lua_Number lf = fltvalue(l);  /* 'l' must be float */
      if (ttisfloat(r))
        return luai_numle(lf, fltvalue(r));  /* both are float */
      else  /* 'l' is float and 'r' is int */
        return LEfloatint(lf, ivalue(r));
    }
  }
  
  
  /*
  ** return 'l < r' for non-numbers.
  */
  static int lessthanothers (lua_State *L, const TValue *l, const TValue *r) {
    lua_assert(!ttisnumber(l) || !ttisnumber(r));
    if (ttisstring(l) && ttisstring(r))  /* both are strings? */
      return l_strcmp(tsvalue(l), tsvalue(r)) < 0;
    else
      return luaT_callorderTM(L, l, r, TM_LT);
  }
  
  
  /*
  ** Main operation less than; return 'l < r'.
  */
  int luaV_lessthan (lua_State *L, const TValue *l, const TValue *r) {
    if (ttisnumber(l) && ttisnumber(r))  /* both operands are numbers? */
      return LTnum(l, r);
    else return lessthanothers(L, l, r);
  }
  
  
  /*
  ** return 'l <= r' for non-numbers.
  */
  static int lessequalothers (lua_State *L, const TValue *l, const TValue *r) {
    lua_assert(!ttisnumber(l) || !ttisnumber(r));
    if (ttisstring(l) && ttisstring(r))  /* both are strings? */
      return l_strcmp(tsvalue(l), tsvalue(r)) <= 0;
    else
      return luaT_callorderTM(L, l, r, TM_LE);
  }
  
  
  /*
  ** Main operation less than or equal to; return 'l <= r'.
  */
  int luaV_lessequal (lua_State *L, const TValue *l, const TValue *r) {
    if (ttisnumber(l) && ttisnumber(r))  /* both operands are numbers? */
      return LEnum(l, r);
    else return lessequalothers(L, l, r);
  }
  
  
  /*
  ** Main operation for equality of Lua values; return 't1 == t2'.
  ** L == NULL means raw equality (no metamethods)
  */
  int luaV_equalobj (lua_State *L, const TValue *t1, const TValue *t2) {
    const TValue *tm;
    if (ttypetag(t1) != ttypetag(t2)) {  /* not the same variant? */
      if (ttype(t1) != ttype(t2) || ttype(t1) != LUA_TNUMBER)
        return 0;  /* only numbers can be equal with different variants */
      else {  /* two numbers with different variants */
        lua_Integer i1, i2;  /* compare them as integers */
        return (tointegerns(t1, &i1) && tointegerns(t2, &i2) && i1 == i2);
      }
    }
    /* values have same type and same variant */
    switch (ttypetag(t1)) {
      case LUA_VNIL: case LUA_VFALSE: case LUA_VTRUE: return 1;
      case LUA_VNUMINT: return (ivalue(t1) == ivalue(t2));
      case LUA_VNUMFLT: return luai_numeq(fltvalue(t1), fltvalue(t2));
      case LUA_VLIGHTUSERDATA: return pvalue(t1) == pvalue(t2);
      case LUA_VLCF: return fvalue(t1) == fvalue(t2);
      case LUA_VSHRSTR: return eqshrstr(tsvalue(t1), tsvalue(t2));
      case LUA_VLNGSTR: return luaS_eqlngstr(tsvalue(t1), tsvalue(t2));
      case LUA_VUSERDATA: {
        if (uvalue(t1) == uvalue(t2)) return 1;
        else if (L == NULL) return 0;
        tm = fasttm(L, uvalue(t1)->metatable, TM_EQ);
        if (tm == NULL)
          tm = fasttm(L, uvalue(t2)->metatable, TM_EQ);
        break;  /* will try TM */
      }
      case LUA_VTABLE: {
        if (hvalue(t1) == hvalue(t2)) return 1;
        else if (L == NULL) return 0;
        tm = fasttm(L, hvalue(t1)->metatable, TM_EQ);
        if (tm == NULL)
          tm = fasttm(L, hvalue(t2)->metatable, TM_EQ);
        break;  /* will try TM */
      }
      default:
        return gcvalue(t1) == gcvalue(t2);
    }
    if (tm == NULL)  /* no TM? */
      return 0;  /* objects are different */
    else {
      luaT_callTMres(L, tm, t1, t2, L->top);  /* call TM */
      return !l_isfalse(s2v(L->top));
    }
  }
  
  
  /* macro used by 'luaV_concat' to ensure that element at 'o' is a string */
  #define tostring(L,o)  \
  	(ttisstring(o) || (cvt2str(o) && (luaO_tostring(L, o), 1)))
  
  #define isemptystr(o)	(ttisshrstring(o) && tsvalue(o)->shrlen == 0)
  
  /* copy strings in stack from top - n up to top - 1 to buffer */
  static void copy2buff (StkId top, int n, char *buff) {
    size_t tl = 0;  /* size already copied */
    do {
      size_t l = vslen(s2v(top - n));  /* length of string being copied */
      memcpy(buff + tl, svalue(s2v(top - n)), l * sizeof(char));
      tl += l;
    } while (--n > 0);
  }
  
  
  /*
  ** Main operation for concatenation: concat 'total' values in the stack,
  ** from 'L->top - total' up to 'L->top - 1'.
  */
  void luaV_concat (lua_State *L, int total) {
    if (total == 1)
      return;  /* "all" values already concatenated */
    do {
      StkId top = L->top;
      int n = 2;  /* number of elements handled in this pass (at least 2) */
      if (!(ttisstring(s2v(top - 2)) || cvt2str(s2v(top - 2))) ||
          !tostring(L, s2v(top - 1)))
        luaT_tryconcatTM(L);
      else if (isemptystr(s2v(top - 1)))  /* second operand is empty? */
        cast_void(tostring(L, s2v(top - 2)));  /* result is first operand */
      else if (isemptystr(s2v(top - 2))) {  /* first operand is empty string? */
        setobjs2s(L, top - 2, top - 1);  /* result is second op. */
      }
      else {
        /* at least two non-empty string values; get as many as possible */
        size_t tl = vslen(s2v(top - 1));
        TString *ts;
        /* collect total length and number of strings */
        for (n = 1; n < total && tostring(L, s2v(top - n - 1)); n++) {
          size_t l = vslen(s2v(top - n - 1));
          if (unlikely(l >= (MAX_SIZE/sizeof(char)) - tl))
            luaG_runerror(L, "string length overflow");
          tl += l;
        }
        if (tl <= LUAI_MAXSHORTLEN) {  /* is result a short string? */
          char buff[LUAI_MAXSHORTLEN];
          copy2buff(top, n, buff);  /* copy strings to buffer */
          ts = luaS_newlstr(L, buff, tl);
        }
        else {  /* long string; copy strings directly to final result */
          ts = luaS_createlngstrobj(L, tl);
          copy2buff(top, n, getstr(ts));
        }
        setsvalue2s(L, top - n, ts);  /* create result */
      }
      total -= n-1;  /* got 'n' strings to create 1 new */
      L->top -= n-1;  /* popped 'n' strings and pushed one */
    } while (total > 1);  /* repeat until only 1 result left */
  }
  
  
  /*
  ** Main operation 'ra = #rb'.
  */
  void luaV_objlen (lua_State *L, StkId ra, const TValue *rb) {
    const TValue *tm;
    switch (ttypetag(rb)) {
      case LUA_VTABLE: {
        Table *h = hvalue(rb);
        tm = fasttm(L, h->metatable, TM_LEN);
        if (tm) break;  /* metamethod? break switch to call it */
        setivalue(s2v(ra), luaH_getn(h));  /* else primitive len */
        return;
      }
      case LUA_VSHRSTR: {
        setivalue(s2v(ra), tsvalue(rb)->shrlen);
        return;
      }
      case LUA_VLNGSTR: {
        setivalue(s2v(ra), tsvalue(rb)->u.lnglen);
        return;
      }
      default: {  /* try metamethod */
        tm = luaT_gettmbyobj(L, rb, TM_LEN);
        if (unlikely(notm(tm)))  /* no metamethod? */
          luaG_typeerror(L, rb, "get length of");
        break;
      }
    }
    luaT_callTMres(L, tm, rb, rb, ra);
  }
  
  
  /*
  ** Integer division; return 'm // n', that is, floor(m/n).
  ** C division truncates its result (rounds towards zero).
  ** 'floor(q) == trunc(q)' when 'q >= 0' or when 'q' is integer,
  ** otherwise 'floor(q) == trunc(q) - 1'.
  */
  lua_Integer luaV_idiv (lua_State *L, lua_Integer m, lua_Integer n) {
    if (unlikely(l_castS2U(n) + 1u <= 1u)) {  /* special cases: -1 or 0 */
      if (n == 0)
        luaG_runerror(L, "attempt to divide by zero");
      return intop(-, 0, m);   /* n==-1; avoid overflow with 0x80000...//-1 */
    }
    else {
      lua_Integer q = m / n;  /* perform C division */
      if ((m ^ n) < 0 && m % n != 0)  /* 'm/n' would be negative non-integer? */
        q -= 1;  /* correct result for different rounding */
      return q;
    }
  }
  
  
  /*
  ** Integer modulus; return 'm % n'. (Assume that C '%' with
  ** negative operands follows C99 behavior. See previous comment
  ** about luaV_idiv.)
  */
  lua_Integer luaV_mod (lua_State *L, lua_Integer m, lua_Integer n) {
    if (unlikely(l_castS2U(n) + 1u <= 1u)) {  /* special cases: -1 or 0 */
      if (n == 0)
        luaG_runerror(L, "attempt to perform 'n%%0'");
      return 0;   /* m % -1 == 0; avoid overflow with 0x80000...%-1 */
    }
    else {
      lua_Integer r = m % n;
      if (r != 0 && (r ^ n) < 0)  /* 'm/n' would be non-integer negative? */
        r += n;  /* correct result for different rounding */
      return r;
    }
  }
  
  
  /*
  ** Float modulus
  */
  lua_Number luaV_modf (lua_State *L, lua_Number m, lua_Number n) {
    lua_Number r;
    luai_nummod(L, m, n, r);
    return r;
  }
  
  
  /* number of bits in an integer */
  #define NBITS	cast_int(sizeof(lua_Integer) * CHAR_BIT)
  
  /*
  ** Shift left operation. (Shift right just negates 'y'.)
  */
  #define luaV_shiftr(x,y)	luaV_shiftl(x,-(y))
  
  lua_Integer luaV_shiftl (lua_Integer x, lua_Integer y) {
    if (y < 0) {  /* shift right? */
      if (y <= -NBITS) return 0;
      else return intop(>>, x, -y);
    }
    else {  /* shift left */
      if (y >= NBITS) return 0;
      else return intop(<<, x, y);
    }
  }
  
  
  /*
  ** create a new Lua closure, push it in the stack, and initialize
  ** its upvalues.
  */
  static void pushclosure (lua_State *L, Proto *p, UpVal **encup, StkId base,
                           StkId ra) {
    int nup = p->sizeupvalues;
    Upvaldesc *uv = p->upvalues;
    int i;
    LClosure *ncl = luaF_newLclosure(L, nup);
    ncl->p = p;
    setclLvalue2s(L, ra, ncl);  /* anchor new closure in stack */
    for (i = 0; i < nup; i++) {  /* fill in its upvalues */
      if (uv[i].instack)  /* upvalue refers to local variable? */
        ncl->upvals[i] = luaF_findupval(L, base + uv[i].idx);
      else  /* get upvalue from enclosing function */
        ncl->upvals[i] = encup[uv[i].idx];
      luaC_objbarrier(L, ncl, ncl->upvals[i]);
    }
  }
  
  
  /*
  ** finish execution of an opcode interrupted by a yield
  */
  void luaV_finishOp (lua_State *L) {
    CallInfo *ci = L->ci;
    StkId base = ci->func + 1;
    Instruction inst = *(ci->u.l.savedpc - 1);  /* interrupted instruction */
    OpCode op = GET_OPCODE(inst);
    switch (op) {  /* finish its execution */
      case OP_MMBIN: case OP_MMBINI: case OP_MMBINK: {
        setobjs2s(L, base + GETARG_A(*(ci->u.l.savedpc - 2)), --L->top);
        break;
      }
      case OP_UNM: case OP_BNOT: case OP_LEN:
      case OP_GETTABUP: case OP_GETTABLE: case OP_GETI:
      case OP_GETFIELD: case OP_SELF: {
        setobjs2s(L, base + GETARG_A(inst), --L->top);
        break;
      }
      case OP_LT: case OP_LE:
      case OP_LTI: case OP_LEI:
      case OP_GTI: case OP_GEI:
      case OP_EQ: {  /* note that 'OP_EQI'/'OP_EQK' cannot yield */
        int res = !l_isfalse(s2v(L->top - 1));
        L->top--;
  #if defined(LUA_COMPAT_LT_LE)
        if (ci->callstatus & CIST_LEQ) {  /* "<=" using "<" instead? */
          ci->callstatus ^= CIST_LEQ;  /* clear mark */
          res = !res;  /* negate result */
        }
  #endif
        lua_assert(GET_OPCODE(*ci->u.l.savedpc) == OP_JMP);
        if (res != GETARG_k(inst))  /* condition failed? */
          ci->u.l.savedpc++;  /* skip jump instruction */
        break;
      }
      case OP_CONCAT: {
        StkId top = L->top - 1;  /* top when 'luaT_tryconcatTM' was called */
        int a = GETARG_A(inst);      /* first element to concatenate */
        int total = cast_int(top - 1 - (base + a));  /* yet to concatenate */
        setobjs2s(L, top - 2, top);  /* put TM result in proper position */
        L->top = top - 1;  /* top is one after last element (at top-2) */
        luaV_concat(L, total);  /* concat them (may yield again) */
        break;
      }
      default: {
        /* only these other opcodes can yield */
        lua_assert(op == OP_TFORCALL || op == OP_CALL ||
             op == OP_TAILCALL || op == OP_SETTABUP || op == OP_SETTABLE ||
             op == OP_SETI || op == OP_SETFIELD);
        break;
      }
    }
  }
  
  
  
  
  /*
  ** {==================================================================
  ** Macros for arithmetic/bitwise/comparison opcodes in 'luaV_execute'
  ** ===================================================================
  */
  
  #define l_addi(L,a,b)	intop(+, a, b)
  #define l_subi(L,a,b)	intop(-, a, b)
  #define l_muli(L,a,b)	intop(*, a, b)
  #define l_band(a,b)	intop(&, a, b)
  #define l_bor(a,b)	intop(|, a, b)
  #define l_bxor(a,b)	intop(^, a, b)
  
  #define l_lti(a,b)	(a < b)
  #define l_lei(a,b)	(a <= b)
  #define l_gti(a,b)	(a > b)
  #define l_gei(a,b)	(a >= b)
  
  
  /*
  ** Arithmetic operations with immediate operands. 'iop' is the integer
  ** operation, 'fop' is the float operation.
  */
  #define op_arithI(L,iop,fop) {  \
    TValue *v1 = vRB(i);  \
    int imm = GETARG_sC(i);  \
    if (ttisinteger(v1)) {  \
      lua_Integer iv1 = ivalue(v1);  \
      pc++; setivalue(s2v(ra), iop(L, iv1, imm));  \
    }  \
    else if (ttisfloat(v1)) {  \
      lua_Number nb = fltvalue(v1);  \
      lua_Number fimm = cast_num(imm);  \
      pc++; setfltvalue(s2v(ra), fop(L, nb, fimm)); \
    }}
  
  
  /*
  ** Auxiliary function for arithmetic operations over floats and others
  ** with two register operands.
  */
  #define op_arithf_aux(L,v1,v2,fop) {  \
    lua_Number n1; lua_Number n2;  \
    if (tonumberns(v1, n1) && tonumberns(v2, n2)) {  \
      pc++; setfltvalue(s2v(ra), fop(L, n1, n2));  \
    }}
  
  
  /*
  ** Arithmetic operations over floats and others with register operands.
  */
  #define op_arithf(L,fop) {  \
    TValue *v1 = vRB(i);  \
    TValue *v2 = vRC(i);  \
    op_arithf_aux(L, v1, v2, fop); }
  
  
  /*
  ** Arithmetic operations with K operands for floats.
  */
  #define op_arithfK(L,fop) {  \
    TValue *v1 = vRB(i);  \
    TValue *v2 = KC(i);  \
    op_arithf_aux(L, v1, v2, fop); }
  
  
  /*
  ** Arithmetic operations over integers and floats.
  */
  #define op_arith_aux(L,v1,v2,iop,fop) {  \
    if (ttisinteger(v1) && ttisinteger(v2)) {  \
      lua_Integer i1 = ivalue(v1); lua_Integer i2 = ivalue(v2);  \
      pc++; setivalue(s2v(ra), iop(L, i1, i2));  \
    }  \
    else op_arithf_aux(L, v1, v2, fop); }
  
  
  /*
  ** Arithmetic operations with register operands.
  */
  #define op_arith(L,iop,fop) {  \
    TValue *v1 = vRB(i);  \
    TValue *v2 = vRC(i);  \
    op_arith_aux(L, v1, v2, iop, fop); }
  
  
  /*
  ** Arithmetic operations with K operands.
  */
  #define op_arithK(L,iop,fop) {  \
    TValue *v1 = vRB(i);  \
    TValue *v2 = KC(i);  \
    op_arith_aux(L, v1, v2, iop, fop); }
  
  
  /*
  ** Bitwise operations with constant operand.
  */
  #define op_bitwiseK(L,op) {  \
    TValue *v1 = vRB(i);  \
    TValue *v2 = KC(i);  \
    lua_Integer i1;  \
    lua_Integer i2 = ivalue(v2);  \
    if (tointegerns(v1, &i1)) {  \
      pc++; setivalue(s2v(ra), op(i1, i2));  \
    }}
  
  
  /*
  ** Bitwise operations with register operands.
  */
  #define op_bitwise(L,op) {  \
    TValue *v1 = vRB(i);  \
    TValue *v2 = vRC(i);  \
    lua_Integer i1; lua_Integer i2;  \
    if (tointegerns(v1, &i1) && tointegerns(v2, &i2)) {  \
      pc++; setivalue(s2v(ra), op(i1, i2));  \
    }}
  
  
  /*
  ** Order operations with register operands. 'opn' actually works
  ** for all numbers, but the fast track improves performance for
  ** integers.
  */
  #define op_order(L,opi,opn,other) {  \
          int cond;  \
          TValue *rb = vRB(i);  \
          if (ttisinteger(s2v(ra)) && ttisinteger(rb)) {  \
            lua_Integer ia = ivalue(s2v(ra));  \
            lua_Integer ib = ivalue(rb);  \
            cond = opi(ia, ib);  \
          }  \
          else if (ttisnumber(s2v(ra)) && ttisnumber(rb))  \
            cond = opn(s2v(ra), rb);  \
          else  \
            Protect(cond = other(L, s2v(ra), rb));  \
          docondjump(); }
  
  
  /*
  ** Order operations with immediate operand. (Immediate operand is
  ** always small enough to have an exact representation as a float.)
  */
  #define op_orderI(L,opi,opf,inv,tm) {  \
          int cond;  \
          int im = GETARG_sB(i);  \
          if (ttisinteger(s2v(ra)))  \
            cond = opi(ivalue(s2v(ra)), im);  \
          else if (ttisfloat(s2v(ra))) {  \
            lua_Number fa = fltvalue(s2v(ra));  \
            lua_Number fim = cast_num(im);  \
            cond = opf(fa, fim);  \
          }  \
          else {  \
            int isf = GETARG_C(i);  \
            Protect(cond = luaT_callorderiTM(L, s2v(ra), im, inv, isf, tm));  \
          }  \
          docondjump(); }
  
  /* }================================================================== */
  
  
  /*
  ** {==================================================================
  ** Function 'luaV_execute': main interpreter loop
  ** ===================================================================
  */
  
  /*
  ** some macros for common tasks in 'luaV_execute'
  */
  
  
  #define RA(i)	(base+GETARG_A(i))
  #define RB(i)	(base+GETARG_B(i))
  #define vRB(i)	s2v(RB(i))
  #define KB(i)	(k+GETARG_B(i))
  #define RC(i)	(base+GETARG_C(i))
  #define vRC(i)	s2v(RC(i))
  #define KC(i)	(k+GETARG_C(i))
  #define RKC(i)	((TESTARG_k(i)) ? k + GETARG_C(i) : s2v(base + GETARG_C(i)))
  
  
  
  #define updatetrap(ci)  (trap = ci->u.l.trap)
  
  #define updatebase(ci)	(base = ci->func + 1)
  
  
  #define updatestack(ci) { if (trap) { updatebase(ci); ra = RA(i); } }
  
  
  /*
  ** Execute a jump instruction. The 'updatetrap' allows signals to stop
  ** tight loops. (Without it, the local copy of 'trap' could never change.)
  */
  #define dojump(ci,i,e)	{ pc += GETARG_sJ(i) + e; updatetrap(ci); }
  
  
  /* for test instructions, execute the jump instruction that follows it */
  #define donextjump(ci)	{ Instruction ni = *pc; dojump(ci, ni, 1); }
  
  /*
  ** do a conditional jump: skip next instruction if 'cond' is not what
  ** was expected (parameter 'k'), else do next instruction, which must
  ** be a jump.
  */
  #define docondjump()	if (cond != GETARG_k(i)) pc++; else donextjump(ci);
  
  
  /*
  ** Correct global 'pc'.
  */
  #define savepc(L)	(ci->u.l.savedpc = pc)
  
  
  /*
  ** Whenever code can raise errors, the global 'pc' and the global
  ** 'top' must be correct to report occasional errors.
  */
  #define savestate(L,ci)		(savepc(L), L->top = ci->top)
  
  
  /*
  ** Protect code that, in general, can raise errors, reallocate the
  ** stack, and change the hooks.
  */
  #define Protect(exp)  (savestate(L,ci), (exp), updatetrap(ci))
  
  /* special version that does not change the top */
  #define ProtectNT(exp)  (savepc(L), (exp), updatetrap(ci))
  
  /*
  ** Protect code that will finish the loop (returns) or can only raise
  ** errors. (That is, it will not return to the interpreter main loop
  ** after changing the stack or hooks.)
  */
  #define halfProtect(exp)  (savestate(L,ci), (exp))
  
  /* idem, but without changing the stack */
  #define halfProtectNT(exp)  (savepc(L), (exp))
  
  /* 'c' is the limit of live values in the stack */
  #define checkGC(L,c)  \
  	{ luaC_condGC(L, (savepc(L), L->top = (c)), \
                           updatetrap(ci)); \
             luai_threadyield(L); }
  
  
  /* fetch an instruction and prepare its execution */
  #define vmfetch()	{ \
    if (trap) {  /* stack reallocation or hooks? */ \
      trap = luaG_traceexec(L, pc);  /* handle hooks */ \
      updatebase(ci);  /* correct stack */ \
    } \
    i = *(pc++); \
    ra = RA(i); /* WARNING: any stack reallocation invalidates 'ra' */ \
  }
  
  #define vmdispatch(o)	switch(o)
  #define vmcase(l)	case l:
  #define vmbreak		break
  
  
  void luaV_execute (lua_State *L, CallInfo *ci) {
    LClosure *cl;
    TValue *k;
    StkId base;
    const Instruction *pc;
    int trap;
  #if LUA_USE_JUMPTABLE
  #include "ljumptab.h"
  #endif
   tailcall:
    trap = L->hookmask;
    cl = clLvalue(s2v(ci->func));
    k = cl->p->k;
    pc = ci->u.l.savedpc;
    if (trap) {
      if (cl->p->is_vararg)
        trap = 0;  /* hooks will start after VARARGPREP instruction */
      else if (pc == cl->p->code)  /* first instruction (not resuming)? */
        luaD_hookcall(L, ci);
      ci->u.l.trap = 1;  /* there may be other hooks */
    }
    base = ci->func + 1;
    /* main loop of interpreter */
    for (;;) {
      Instruction i;  /* instruction being executed */
      StkId ra;  /* instruction's A register */
      vmfetch();
      lua_assert(base == ci->func + 1);
      lua_assert(base <= L->top && L->top < L->stack + L->stacksize);
      /* invalidate top for instructions not expecting it */
      lua_assert(isIT(i) || (cast_void(L->top = base), 1));
      vmdispatch (GET_OPCODE(i)) {
        vmcase(OP_MOVE) {
          setobjs2s(L, ra, RB(i));
          vmbreak;
        }
        vmcase(OP_LOADI) {
          lua_Integer b = GETARG_sBx(i);
          setivalue(s2v(ra), b);
          vmbreak;
        }
        vmcase(OP_LOADF) {
          int b = GETARG_sBx(i);
          setfltvalue(s2v(ra), cast_num(b));
          vmbreak;
        }
        vmcase(OP_LOADK) {
          TValue *rb = k + GETARG_Bx(i);
          setobj2s(L, ra, rb);
          vmbreak;
        }
        vmcase(OP_LOADKX) {
          TValue *rb;
          rb = k + GETARG_Ax(*pc); pc++;
          setobj2s(L, ra, rb);
          vmbreak;
        }
        vmcase(OP_LOADFALSE) {
          setbfvalue(s2v(ra));
          vmbreak;
        }
        vmcase(OP_LFALSESKIP) {
          setbfvalue(s2v(ra));
          pc++;  /* skip next instruction */
          vmbreak;
        }
        vmcase(OP_LOADTRUE) {
          setbtvalue(s2v(ra));
          vmbreak;
        }
        vmcase(OP_LOADNIL) {
          int b = GETARG_B(i);
          do {
            setnilvalue(s2v(ra++));
          } while (b--);
          vmbreak;
        }
        vmcase(OP_GETUPVAL) {
          int b = GETARG_B(i);
          setobj2s(L, ra, cl->upvals[b]->v);
          vmbreak;
        }
        vmcase(OP_SETUPVAL) {
          UpVal *uv = cl->upvals[GETARG_B(i)];
          setobj(L, uv->v, s2v(ra));
          luaC_barrier(L, uv, s2v(ra));
          vmbreak;
        }
        vmcase(OP_GETTABUP) {
          const TValue *slot;
          TValue *upval = cl->upvals[GETARG_B(i)]->v;
          TValue *rc = KC(i);
          TString *key = tsvalue(rc);  /* key must be a string */
          if (luaV_fastget(L, upval, key, slot, luaH_getshortstr)) {
            setobj2s(L, ra, slot);
          }
          else
            Protect(luaV_finishget(L, upval, rc, ra, slot));
          vmbreak;
        }
        vmcase(OP_GETTABLE) {
          const TValue *slot;
          TValue *rb = vRB(i);
          TValue *rc = vRC(i);
          lua_Unsigned n;
          if (ttisinteger(rc)  /* fast track for integers? */
              ? (cast_void(n = ivalue(rc)), luaV_fastgeti(L, rb, n, slot))
              : luaV_fastget(L, rb, rc, slot, luaH_get)) {
            setobj2s(L, ra, slot);
          }
          else
            Protect(luaV_finishget(L, rb, rc, ra, slot));
          vmbreak;
        }
        vmcase(OP_GETI) {
          const TValue *slot;
          TValue *rb = vRB(i);
          int c = GETARG_C(i);
          if (luaV_fastgeti(L, rb, c, slot)) {
            setobj2s(L, ra, slot);
          }
          else {
            TValue key;
            setivalue(&key, c);
            Protect(luaV_finishget(L, rb, &key, ra, slot));
          }
          vmbreak;
        }
        vmcase(OP_GETFIELD) {
          const TValue *slot;
          TValue *rb = vRB(i);
          TValue *rc = KC(i);
          TString *key = tsvalue(rc);  /* key must be a string */
          if (luaV_fastget(L, rb, key, slot, luaH_getshortstr)) {
            setobj2s(L, ra, slot);
          }
          else
            Protect(luaV_finishget(L, rb, rc, ra, slot));
          vmbreak;
        }
        vmcase(OP_SETTABUP) {
          const TValue *slot;
          TValue *upval = cl->upvals[GETARG_A(i)]->v;
          TValue *rb = KB(i);
          TValue *rc = RKC(i);
          TString *key = tsvalue(rb);  /* key must be a string */
          if (luaV_fastget(L, upval, key, slot, luaH_getshortstr)) {
            luaV_finishfastset(L, upval, slot, rc);
          }
          else
            Protect(luaV_finishset(L, upval, rb, rc, slot));
          vmbreak;
        }
        vmcase(OP_SETTABLE) {
          const TValue *slot;
          TValue *rb = vRB(i);  /* key (table is in 'ra') */
          TValue *rc = RKC(i);  /* value */
          lua_Unsigned n;
          if (ttisinteger(rb)  /* fast track for integers? */
              ? (cast_void(n = ivalue(rb)), luaV_fastgeti(L, s2v(ra), n, slot))
              : luaV_fastget(L, s2v(ra), rb, slot, luaH_get)) {
            luaV_finishfastset(L, s2v(ra), slot, rc);
          }
          else
            Protect(luaV_finishset(L, s2v(ra), rb, rc, slot));
          vmbreak;
        }
        vmcase(OP_SETI) {
          const TValue *slot;
          int c = GETARG_B(i);
          TValue *rc = RKC(i);
          if (luaV_fastgeti(L, s2v(ra), c, slot)) {
            luaV_finishfastset(L, s2v(ra), slot, rc);
          }
          else {
            TValue key;
            setivalue(&key, c);
            Protect(luaV_finishset(L, s2v(ra), &key, rc, slot));
          }
          vmbreak;
        }
        vmcase(OP_SETFIELD) {
          const TValue *slot;
          TValue *rb = KB(i);
          TValue *rc = RKC(i);
          TString *key = tsvalue(rb);  /* key must be a string */
          if (luaV_fastget(L, s2v(ra), key, slot, luaH_getshortstr)) {
            luaV_finishfastset(L, s2v(ra), slot, rc);
          }
          else
            Protect(luaV_finishset(L, s2v(ra), rb, rc, slot));
          vmbreak;
        }
        vmcase(OP_NEWTABLE) {
          int b = GETARG_B(i);  /* log2(hash size) + 1 */
          int c = GETARG_C(i);  /* array size */
          Table *t;
          if (b > 0)
            b = 1 << (b - 1);  /* size is 2^(b - 1) */
          lua_assert((!TESTARG_k(i)) == (GETARG_Ax(*pc) == 0));
          if (TESTARG_k(i))  /* non-zero extra argument? */
            c += GETARG_Ax(*pc) * (MAXARG_C + 1);  /* add it to size */
          pc++;  /* skip extra argument */
          L->top = ra + 1;  /* correct top in case of emergency GC */
          t = luaH_new(L);  /* memory allocation */
          sethvalue2s(L, ra, t);
          if (b != 0 || c != 0)
            luaH_resize(L, t, c, b);  /* idem */
          checkGC(L, ra + 1);
          vmbreak;
        }
        vmcase(OP_SELF) {
          const TValue *slot;
          TValue *rb = vRB(i);
          TValue *rc = RKC(i);
          TString *key = tsvalue(rc);  /* key must be a string */
          setobj2s(L, ra + 1, rb);
          if (luaV_fastget(L, rb, key, slot, luaH_getstr)) {
            setobj2s(L, ra, slot);
          }
          else
            Protect(luaV_finishget(L, rb, rc, ra, slot));
          vmbreak;
        }
        vmcase(OP_ADDI) {
          op_arithI(L, l_addi, luai_numadd);
          vmbreak;
        }
        vmcase(OP_ADDK) {
          op_arithK(L, l_addi, luai_numadd);
          vmbreak;
        }
        vmcase(OP_SUBK) {
          op_arithK(L, l_subi, luai_numsub);
          vmbreak;
        }
        vmcase(OP_MULK) {
          op_arithK(L, l_muli, luai_nummul);
          vmbreak;
        }
        vmcase(OP_MODK) {
          op_arithK(L, luaV_mod, luaV_modf);
          vmbreak;
        }
        vmcase(OP_POWK) {
          op_arithfK(L, luai_numpow);
          vmbreak;
        }
        vmcase(OP_DIVK) {
          op_arithfK(L, luai_numdiv);
          vmbreak;
        }
        vmcase(OP_IDIVK) {
          op_arithK(L, luaV_idiv, luai_numidiv);
          vmbreak;
        }
        vmcase(OP_BANDK) {
          op_bitwiseK(L, l_band);
          vmbreak;
        }
        vmcase(OP_BORK) {
          op_bitwiseK(L, l_bor);
          vmbreak;
        }
        vmcase(OP_BXORK) {
          op_bitwiseK(L, l_bxor);
          vmbreak;
        }
        vmcase(OP_SHRI) {
          TValue *rb = vRB(i);
          int ic = GETARG_sC(i);
          lua_Integer ib;
          if (tointegerns(rb, &ib)) {
            pc++; setivalue(s2v(ra), luaV_shiftl(ib, -ic));
          }
          vmbreak;
        }
        vmcase(OP_SHLI) {
          TValue *rb = vRB(i);
          int ic = GETARG_sC(i);
          lua_Integer ib;
          if (tointegerns(rb, &ib)) {
            pc++; setivalue(s2v(ra), luaV_shiftl(ic, ib));
          }
          vmbreak;
        }
        vmcase(OP_ADD) {
          op_arith(L, l_addi, luai_numadd);
          vmbreak;
        }
        vmcase(OP_SUB) {
          op_arith(L, l_subi, luai_numsub);
          vmbreak;
        }
        vmcase(OP_MUL) {
          op_arith(L, l_muli, luai_nummul);
          vmbreak;
        }
        vmcase(OP_MOD) {
          op_arith(L, luaV_mod, luaV_modf);
          vmbreak;
        }
        vmcase(OP_POW) {
          op_arithf(L, luai_numpow);
          vmbreak;
        }
        vmcase(OP_DIV) {  /* float division (always with floats) */
          op_arithf(L, luai_numdiv);
          vmbreak;
        }
        vmcase(OP_IDIV) {  /* floor division */
          op_arith(L, luaV_idiv, luai_numidiv);
          vmbreak;
        }
        vmcase(OP_BAND) {
          op_bitwise(L, l_band);
          vmbreak;
        }
        vmcase(OP_BOR) {
          op_bitwise(L, l_bor);
          vmbreak;
        }
        vmcase(OP_BXOR) {
          op_bitwise(L, l_bxor);
          vmbreak;
        }
        vmcase(OP_SHR) {
          op_bitwise(L, luaV_shiftr);
          vmbreak;
        }
        vmcase(OP_SHL) {
          op_bitwise(L, luaV_shiftl);
          vmbreak;
        }
        vmcase(OP_MMBIN) {
          Instruction pi = *(pc - 2);  /* original arith. expression */
          TValue *rb = vRB(i);
          TMS tm = (TMS)GETARG_C(i);
          StkId result = RA(pi);
          lua_assert(OP_ADD <= GET_OPCODE(pi) && GET_OPCODE(pi) <= OP_SHR);
          Protect(luaT_trybinTM(L, s2v(ra), rb, result, tm));
          vmbreak;
        }
        vmcase(OP_MMBINI) {
          Instruction pi = *(pc - 2);  /* original arith. expression */
          int imm = GETARG_sB(i);
          TMS tm = (TMS)GETARG_C(i);
          int flip = GETARG_k(i);
          StkId result = RA(pi);
          Protect(luaT_trybiniTM(L, s2v(ra), imm, flip, result, tm));
          vmbreak;
        }
        vmcase(OP_MMBINK) {
          Instruction pi = *(pc - 2);  /* original arith. expression */
          TValue *imm = KB(i);
          TMS tm = (TMS)GETARG_C(i);
          int flip = GETARG_k(i);
          StkId result = RA(pi);
          Protect(luaT_trybinassocTM(L, s2v(ra), imm, flip, result, tm));
          vmbreak;
        }
        vmcase(OP_UNM) {
          TValue *rb = vRB(i);
          lua_Number nb;
          if (ttisinteger(rb)) {
            lua_Integer ib = ivalue(rb);
            setivalue(s2v(ra), intop(-, 0, ib));
          }
          else if (tonumberns(rb, nb)) {
            setfltvalue(s2v(ra), luai_numunm(L, nb));
          }
          else
            Protect(luaT_trybinTM(L, rb, rb, ra, TM_UNM));
          vmbreak;
        }
        vmcase(OP_BNOT) {
          TValue *rb = vRB(i);
          lua_Integer ib;
          if (tointegerns(rb, &ib)) {
            setivalue(s2v(ra), intop(^, ~l_castS2U(0), ib));
          }
          else
            Protect(luaT_trybinTM(L, rb, rb, ra, TM_BNOT));
          vmbreak;
        }
        vmcase(OP_NOT) {
          TValue *rb = vRB(i);
          if (l_isfalse(rb))
            setbtvalue(s2v(ra));
          else
            setbfvalue(s2v(ra));
          vmbreak;
        }
        vmcase(OP_LEN) {
          Protect(luaV_objlen(L, ra, vRB(i)));
          vmbreak;
        }
        vmcase(OP_CONCAT) {
          int n = GETARG_B(i);  /* number of elements to concatenate */
          L->top = ra + n;  /* mark the end of concat operands */
          ProtectNT(luaV_concat(L, n));
          checkGC(L, L->top); /* 'luaV_concat' ensures correct top */
          vmbreak;
        }
        vmcase(OP_CLOSE) {
          Protect(luaF_close(L, ra, LUA_OK));
          vmbreak;
        }
        vmcase(OP_TBC) {
          /* create new to-be-closed upvalue */
          halfProtect(luaF_newtbcupval(L, ra));
          vmbreak;
        }
        vmcase(OP_JMP) {
          dojump(ci, i, 0);
          vmbreak;
        }
        vmcase(OP_EQ) {
          int cond;
          TValue *rb = vRB(i);
          Protect(cond = luaV_equalobj(L, s2v(ra), rb));
          docondjump();
          vmbreak;
        }
        vmcase(OP_LT) {
          op_order(L, l_lti, LTnum, lessthanothers);
          vmbreak;
        }
        vmcase(OP_LE) {
          op_order(L, l_lei, LEnum, lessequalothers);
          vmbreak;
        }
        vmcase(OP_EQK) {
          TValue *rb = KB(i);
          /* basic types do not use '__eq'; we can use raw equality */
          int cond = luaV_rawequalobj(s2v(ra), rb);
          docondjump();
          vmbreak;
        }
        vmcase(OP_EQI) {
          int cond;
          int im = GETARG_sB(i);
          if (ttisinteger(s2v(ra)))
            cond = (ivalue(s2v(ra)) == im);
          else if (ttisfloat(s2v(ra)))
            cond = luai_numeq(fltvalue(s2v(ra)), cast_num(im));
          else
            cond = 0;  /* other types cannot be equal to a number */
          docondjump();
          vmbreak;
        }
        vmcase(OP_LTI) {
          op_orderI(L, l_lti, luai_numlt, 0, TM_LT);
          vmbreak;
        }
        vmcase(OP_LEI) {
          op_orderI(L, l_lei, luai_numle, 0, TM_LE);
          vmbreak;
        }
        vmcase(OP_GTI) {
          op_orderI(L, l_gti, luai_numgt, 1, TM_LT);
          vmbreak;
        }
        vmcase(OP_GEI) {
          op_orderI(L, l_gei, luai_numge, 1, TM_LE);
          vmbreak;
        }
        vmcase(OP_TEST) {
          int cond = !l_isfalse(s2v(ra));
          docondjump();
          vmbreak;
        }
        vmcase(OP_TESTSET) {
          TValue *rb = vRB(i);
          if (l_isfalse(rb) == GETARG_k(i))
            pc++;
          else {
            setobj2s(L, ra, rb);
            donextjump(ci);
          }
          vmbreak;
        }
        vmcase(OP_CALL) {
          int b = GETARG_B(i);
          int nresults = GETARG_C(i) - 1;
          if (b != 0)  /* fixed number of arguments? */
            L->top = ra + b;  /* top signals number of arguments */
          /* else previous instruction set top */
          ProtectNT(luaD_call(L, ra, nresults));
          vmbreak;
        }
        vmcase(OP_TAILCALL) {
          int b = GETARG_B(i);  /* number of arguments + 1 (function) */
          int nparams1 = GETARG_C(i);
          /* delat is virtual 'func' - real 'func' (vararg functions) */
          int delta = (nparams1) ? ci->u.l.nextraargs + nparams1 : 0;
          if (b != 0)
            L->top = ra + b;
          else  /* previous instruction set top */
            b = cast_int(L->top - ra);
          savepc(ci);  /* some calls here can raise errors */
          if (TESTARG_k(i)) {
            /* close upvalues from current call; the compiler ensures
               that there are no to-be-closed variables here, so this
               call cannot change the stack */
            luaF_close(L, base, NOCLOSINGMETH);
            lua_assert(base == ci->func + 1);
          }
          while (!ttisfunction(s2v(ra))) {  /* not a function? */
            luaD_tryfuncTM(L, ra);  /* try '__call' metamethod */
            b++;  /* there is now one extra argument */
            checkstackGCp(L, 1, ra);
          }
          if (!ttisLclosure(s2v(ra))) {  /* C function? */
            luaD_call(L, ra, LUA_MULTRET);  /* call it */
            updatetrap(ci);
            updatestack(ci);  /* stack may have been relocated */
            ci->func -= delta;
            luaD_poscall(L, ci, cast_int(L->top - ra));
            return;
          }
          ci->func -= delta;
          luaD_pretailcall(L, ci, ra, b);  /* prepare call frame */
          goto tailcall;
        }
        vmcase(OP_RETURN) {
          int n = GETARG_B(i) - 1;  /* number of results */
          int nparams1 = GETARG_C(i);
          if (n < 0)  /* not fixed? */
            n = cast_int(L->top - ra);  /* get what is available */
          savepc(ci);
          if (TESTARG_k(i)) {  /* may there be open upvalues? */
            if (L->top < ci->top)
              L->top = ci->top;
            luaF_close(L, base, LUA_OK);
            updatetrap(ci);
            updatestack(ci);
          }
          if (nparams1)  /* vararg function? */
            ci->func -= ci->u.l.nextraargs + nparams1;
          L->top = ra + n;  /* set call for 'luaD_poscall' */
          luaD_poscall(L, ci, n);
          return;
        }
        vmcase(OP_RETURN0) {
          if (L->hookmask) {
            L->top = ra;
            halfProtectNT(luaD_poscall(L, ci, 0));  /* no hurry... */
          }
          else {  /* do the 'poscall' here */
            int nres = ci->nresults;
            L->ci = ci->previous;  /* back to caller */
            L->top = base - 1;
            while (nres-- > 0)
              setnilvalue(s2v(L->top++));  /* all results are nil */
          }
          return;
        }
        vmcase(OP_RETURN1) {
          if (L->hookmask) {
            L->top = ra + 1;
            halfProtectNT(luaD_poscall(L, ci, 1));  /* no hurry... */
          }
          else {  /* do the 'poscall' here */
            int nres = ci->nresults;
            L->ci = ci->previous;  /* back to caller */
            if (nres == 0)
              L->top = base - 1;  /* asked for no results */
            else {
              setobjs2s(L, base - 1, ra);  /* at least this result */
              L->top = base;
              while (--nres > 0)  /* complete missing results */
                setnilvalue(s2v(L->top++));
            }
          }
          return;
        }
        vmcase(OP_FORLOOP) {
          if (ttisinteger(s2v(ra + 2))) {  /* integer loop? */
            lua_Unsigned count = l_castS2U(ivalue(s2v(ra + 1)));
            if (count > 0) {  /* still more iterations? */
              lua_Integer step = ivalue(s2v(ra + 2));
              lua_Integer idx = ivalue(s2v(ra));  /* internal index */
              chgivalue(s2v(ra + 1), count - 1);  /* update counter */
              idx = intop(+, idx, step);  /* add step to index */
              chgivalue(s2v(ra), idx);  /* update internal index */
              setivalue(s2v(ra + 3), idx);  /* and control variable */
              pc -= GETARG_Bx(i);  /* jump back */
            }
          }
          else if (floatforloop(ra))  /* float loop */
            pc -= GETARG_Bx(i);  /* jump back */
          updatetrap(ci);  /* allows a signal to break the loop */
          vmbreak;
        }
        vmcase(OP_FORPREP) {
          savestate(L, ci);  /* in case of errors */
          if (forprep(L, ra))
            pc += GETARG_Bx(i) + 1;  /* skip the loop */
          vmbreak;
        }
        vmcase(OP_TFORPREP) {
          /* create to-be-closed upvalue (if needed) */
          halfProtect(luaF_newtbcupval(L, ra + 3));
          pc += GETARG_Bx(i);
          i = *(pc++);  /* go to next instruction */
          lua_assert(GET_OPCODE(i) == OP_TFORCALL && ra == RA(i));
          goto l_tforcall;
        }
        vmcase(OP_TFORCALL) {
         l_tforcall:
          /* 'ra' has the iterator function, 'ra + 1' has the state,
             'ra + 2' has the control variable, and 'ra + 3' has the
             to-be-closed variable. The call will use the stack after
             these values (starting at 'ra + 4')
          */
          /* push function, state, and control variable */
          memcpy(ra + 4, ra, 3 * sizeof(*ra));
          L->top = ra + 4 + 3;
          ProtectNT(luaD_call(L, ra + 4, GETARG_C(i)));  /* do the call */
          updatestack(ci);  /* stack may have changed */
          i = *(pc++);  /* go to next instruction */
          lua_assert(GET_OPCODE(i) == OP_TFORLOOP && ra == RA(i));
          goto l_tforloop;
        }
        vmcase(OP_TFORLOOP) {
          l_tforloop:
          if (!ttisnil(s2v(ra + 4))) {  /* continue loop? */
            setobjs2s(L, ra + 2, ra + 4);  /* save control variable */
            pc -= GETARG_Bx(i);  /* jump back */
          }
          vmbreak;
        }
        vmcase(OP_SETLIST) {
          int n = GETARG_B(i);
          unsigned int last = GETARG_C(i);
          Table *h = hvalue(s2v(ra));
          if (n == 0)
            n = cast_int(L->top - ra) - 1;  /* get up to the top */
          else
            L->top = ci->top;  /* correct top in case of emergency GC */
          last += n;
          if (TESTARG_k(i)) {
            last += GETARG_Ax(*pc) * (MAXARG_C + 1);
            pc++;
          }
          if (last > luaH_realasize(h))  /* needs more space? */
            luaH_resizearray(L, h, last);  /* preallocate it at once */
          for (; n > 0; n--) {
            TValue *val = s2v(ra + n);
            setobj2t(L, &h->array[last - 1], val);
            last--;
            luaC_barrierback(L, obj2gco(h), val);
          }
          vmbreak;
        }
        vmcase(OP_CLOSURE) {
          Proto *p = cl->p->p[GETARG_Bx(i)];
          halfProtect(pushclosure(L, p, cl->upvals, base, ra));
          checkGC(L, ra + 1);
          vmbreak;
        }
        vmcase(OP_VARARG) {
          int n = GETARG_C(i) - 1;  /* required results */
          Protect(luaT_getvarargs(L, ci, ra, n));
          vmbreak;
        }
        vmcase(OP_VARARGPREP) {
          ProtectNT(luaT_adjustvarargs(L, GETARG_A(i), ci, cl->p));
          if (trap) {
            luaD_hookcall(L, ci);
            L->oldpc = pc + 1;  /* next opcode will be seen as a "new" line */
          }
          updatebase(ci);  /* function has new base after adjustment */
          vmbreak;
        }
        vmcase(OP_EXTRAARG) {
          lua_assert(0);
          vmbreak;
        }
      }
    }
  }
  
  /* }================================================================== */
  