lua

lvm.c (59757B)

---

 /*
 ** $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 "lapi.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 {
     TString *st = tsvalue(obj);
     size_t stlen;
     const char *s = getlstr(st, stlen);
     return (luaO_str2num(s, result) == stlen + 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 ceiling? */
       f += 1;  /* convert floor to ceiling (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).
 ** Before execution, stack is as follows:
 **   ra     : initial value
 **   ra + 1 : limit
 **   ra + 2 : step
 ** Return true to skip the loop. Otherwise,
 ** after preparation, stack will be as follows:
 **   ra     : loop counter (integer loops) or limit (float loops)
 **   ra + 1 : step
 **   ra + 2 : 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");
     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;
       }
       /* use 'chgivalue' for places that for sure had integers */
       chgivalue(s2v(ra), l_castU2S(count));  /* change init to count */
       setivalue(s2v(ra + 1), step);  /* change limit to step */
       chgivalue(s2v(ra + 2), init);  /* change step to init */
     }
   }
   else {  /* try making all values floats */
     lua_Number init; lua_Number limit; lua_Number step;
     if (l_unlikely(!tonumber(plimit, &limit)))
       luaG_forerror(L, plimit, "limit");
     if (l_unlikely(!tonumber(pstep, &step)))
       luaG_forerror(L, pstep, "step");
     if (l_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 all values are floats */
       setfltvalue(s2v(ra), limit);
       setfltvalue(s2v(ra + 1), step);
       setfltvalue(s2v(ra + 2), 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 + 1));
   lua_Number limit = fltvalue(s2v(ra));
   lua_Number idx = fltvalue(s2v(ra + 2));  /* control variable */
   idx = luai_numadd(L, idx, step);  /* increment index */
   if (luai_numlt(0, step) ? luai_numle(idx, limit)
                           : luai_numle(limit, idx)) {
     chgfltvalue(s2v(ra + 2), idx);  /* update control variable */
     return 1;  /* jump back */
   }
   else
     return 0;  /* finish the loop */
 }
 
 
 /*
 ** Finish the table access 'val = t[key]' and return the tag of the result.
 */
 lu_byte luaV_finishget (lua_State *L, const TValue *t, TValue *key,
                                       StkId val, lu_byte tag) {
   int loop;  /* counter to avoid infinite loops */
   const TValue *tm;  /* metamethod */
   for (loop = 0; loop < MAXTAGLOOP; loop++) {
     if (tag == LUA_VNOTABLE) {  /* 't' is not a table? */
       lua_assert(!ttistable(t));
       tm = luaT_gettmbyobj(L, t, TM_INDEX);
       if (l_unlikely(notm(tm)))
         luaG_typeerror(L, t, "index");  /* no metamethod */
       /* else will try the metamethod */
     }
     else {  /* 't' is a table */
       tm = fasttm(L, hvalue(t)->metatable, TM_INDEX);  /* table's metamethod */
       if (tm == NULL) {  /* no metamethod? */
         setnilvalue(s2v(val));  /* result is nil */
         return LUA_VNIL;
       }
       /* else will try the metamethod */
     }
     if (ttisfunction(tm)) {  /* is metamethod a function? */
       tag = luaT_callTMres(L, tm, t, key, val);  /* call it */
       return tag;  /* return tag of the result */
     }
     t = tm;  /* else try to access 'tm[key]' */
     luaV_fastget(t, key, s2v(val), luaH_get, tag);
     if (!tagisempty(tag))
       return tag;  /* done */
     /* else repeat (tail call 'luaV_finishget') */
   }
   luaG_runerror(L, "'__index' chain too long; possible loop");
   return 0;  /* to avoid warnings */
 }
 
 
 /*
 ** Finish a table assignment 't[key] = val'.
 */
 void luaV_finishset (lua_State *L, const TValue *t, TValue *key,
                       TValue *val, int hres) {
   int loop;  /* counter to avoid infinite loops */
   for (loop = 0; loop < MAXTAGLOOP; loop++) {
     const TValue *tm;  /* '__newindex' metamethod */
     if (hres != HNOTATABLE) {  /* is 't' a table? */
       Table *h = hvalue(t);  /* save 't' table */
       tm = fasttm(L, h->metatable, TM_NEWINDEX);  /* get metamethod */
       if (tm == NULL) {  /* no metamethod? */
         luaH_finishset(L, h, key, val, hres);  /* set 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 (l_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' */
     luaV_fastset(t, key, val, hres, luaH_pset);
     if (hres == HOK)
       return;  /* done */
     /* else 'return luaV_finishset(L, t, key, val, slot)' (loop) */
   }
   luaG_runerror(L, "'__newindex' chain too long; possible loop");
 }
 
 
 /*
 ** Compare two strings 'ts1' x 'ts2', returning an integer less-equal-
 ** -greater than zero if 'ts1' is less-equal-greater than 'ts2'.
 ** The code is a little tricky because it allows '\0' in the strings
 ** and it uses 'strcoll' (to respect locales) for each segment
 ** of the strings. Note that segments can compare equal but still
 ** have different lengths.
 */
 static int l_strcmp (const TString *ts1, const TString *ts2) {
   size_t rl1;  /* real length */
   const char *s1 = getlstr(ts1, rl1);
   size_t rl2;
   const char *s2 = getlstr(ts2, rl2);
   for (;;) {  /* for each segment */
     int temp = strcoll(s1, s2);
     if (temp != 0)  /* not equal? */
       return temp;  /* done */
     else {  /* strings are equal up to a '\0' */
       size_t zl1 = strlen(s1);  /* index of first '\0' in 's1' */
       size_t zl2 = strlen(s2);  /* index of first '\0' in 's2' */
       if (zl2 == rl2)  /* 's2' is finished? */
         return (zl1 == rl1) ? 0 : 1;  /* check 's1' */
       else if (zl1 == rl1)  /* 's1' is finished? */
         return -1;  /* 's1' is less than 's2' ('s2' is not finished) */
       /* both strings longer than 'zl'; go on comparing after the '\0' */
       zl1++; zl2++;
       s1 += zl1; rl1 -= zl1; s2 += zl2; rl2 -= zl2;
     }
   }
 }
 
 
 /*
 ** 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.
 */
 l_sinline 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.
 */
 l_sinline 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.
 */
 l_sinline 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.
 */
 l_sinline 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.
 */
 l_sinline 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.
 */
 l_sinline 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 */
       /* One of them is an integer. If the other does not have an
          integer value, they cannot be equal; otherwise, compare their
          integer values. */
       lua_Integer i1, i2;
       return (luaV_tointegerns(t1, &i1, F2Ieq) &&
               luaV_tointegerns(t2, &i2, F2Ieq) &&
               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 {
     int tag = luaT_callTMres(L, tm, t1, t2, L->top.p);  /* call TM */
     return !tagisfalse(tag);
   }
 }
 
 
 /* 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 {
     TString *st = tsvalue(s2v(top - n));
     size_t l;  /* length of string being copied */
     const char *s = getlstr(st, l);
     memcpy(buff + tl, s, l * sizeof(char));
     tl += l;
   } while (--n > 0);
 }
 
 
 /*
 ** Main operation for concatenation: concat 'total' values in the stack,
 ** from 'L->top.p - total' up to 'L->top.p - 1'.
 */
 void luaV_concat (lua_State *L, int total) {
   if (total == 1)
     return;  /* "all" values already concatenated */
   do {
     StkId top = L->top.p;
     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);  /* may invalidate 'top' */
     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 = tsslen(tsvalue(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 = tsslen(tsvalue(s2v(top - n - 1)));
         if (l_unlikely(l >= MAX_SIZE - sizeof(TString) - tl)) {
           L->top.p = top - total;  /* pop strings to avoid wasting stack */
           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, getlngstr(ts));
       }
       setsvalue2s(L, top - n, ts);  /* create result */
     }
     total -= n - 1;  /* got 'n' strings to create one new */
     L->top.p -= 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), l_castU2S(luaH_getn(h)));  /* else primitive len */
       return;
     }
     case LUA_VSHRSTR: {
       setivalue(s2v(ra), tsvalue(rb)->shrlen);
       return;
     }
     case LUA_VLNGSTR: {
       setivalue(s2v(ra), cast_st2S(tsvalue(rb)->u.lnglen));
       return;
     }
     default: {  /* try metamethod */
       tm = luaT_gettmbyobj(L, rb, TM_LEN);
       if (l_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 (l_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 (l_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'.)
 */
 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.p + 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.p);
       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.p);
       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.p - 1));
       L->top.p--;
 #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.p - 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.p = top - 1;  /* top is one after last element (at top-2) */
       luaV_concat(L, total);  /* concat them (may yield again) */
       break;
     }
     case OP_CLOSE: {  /* yielded closing variables */
       ci->u.l.savedpc--;  /* repeat instruction to close other vars. */
       break;
     }
     case OP_RETURN: {  /* yielded closing variables */
       StkId ra = base + GETARG_A(inst);
       /* adjust top to signal correct number of returns, in case the
          return is "up to top" ('isIT') */
       L->top.p = ra + ci->u2.nres;
       /* repeat instruction to close other vars. and complete the return */
       ci->u.l.savedpc--;
       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) {  \
   StkId ra = RA(i); \
   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 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) {  \
   StkId ra = RA(i); \
   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) {  \
   StkId ra = RA(i); \
   TValue *v1 = vRB(i);  \
   TValue *v2 = KC(i); lua_assert(ttisnumber(v2));  \
   op_arithf_aux(L, v1, v2, fop); }
 
 
 /*
 ** Arithmetic operations over integers and floats.
 */
 #define op_arith_aux(L,v1,v2,iop,fop) {  \
   StkId ra = RA(i); \
   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); lua_assert(ttisnumber(v2));  \
   op_arith_aux(L, v1, v2, iop, fop); }
 
 
 /*
 ** Bitwise operations with constant operand.
 */
 #define op_bitwiseK(L,op) {  \
   StkId ra = RA(i); \
   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) {  \
   StkId ra = RA(i); \
   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) {  \
   StkId ra = RA(i); \
   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) {  \
   StkId ra = RA(i); \
   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.p + 1)
 
 
 #define updatestack(ci)  \
 	{ if (l_unlikely(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.p = ci->top.p)
 
 
 /*
 ** 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 can only raise errors. (That is, it cannot change
 ** the stack or hooks.)
 */
 #define halfProtect(exp)  (savestate(L,ci), (exp))
 
 /*
 ** macro executed during Lua functions at points where the
 ** function can yield.
 */
 #if !defined(luai_threadyield)
 #define luai_threadyield(L)	{lua_unlock(L); lua_lock(L);}
 #endif
 
 /* 'c' is the limit of live values in the stack */
 #define checkGC(L,c)  \
 	{ luaC_condGC(L, (savepc(L), L->top.p = (c)), \
                          updatetrap(ci)); \
            luai_threadyield(L); }
 
 
 /* fetch an instruction and prepare its execution */
 #define vmfetch()	{ \
   if (l_unlikely(trap)) {  /* stack reallocation or hooks? */ \
     trap = luaG_traceexec(L, pc);  /* handle hooks */ \
     updatebase(ci);  /* correct stack */ \
   } \
   i = *(pc++); \
 }
 
 #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
  startfunc:
   trap = L->hookmask;
  returning:  /* trap already set */
   cl = ci_func(ci);
   k = cl->p->k;
   pc = ci->u.l.savedpc;
   if (l_unlikely(trap))
     trap = luaG_tracecall(L);
   base = ci->func.p + 1;
   /* main loop of interpreter */
   for (;;) {
     Instruction i;  /* instruction being executed */
     vmfetch();
     #if 0
     { /* low-level line tracing for debugging Lua */
       #include "lopnames.h"
       int pcrel = pcRel(pc, cl->p);
       printf("line: %d; %s (%d)\n", luaG_getfuncline(cl->p, pcrel),
              opnames[GET_OPCODE(i)], pcrel);
     }
     #endif
     lua_assert(base == ci->func.p + 1);
     lua_assert(base <= L->top.p && L->top.p <= L->stack_last.p);
     /* for tests, invalidate top for instructions not expecting it */
     lua_assert(luaP_isIT(i) || (cast_void(L->top.p = base), 1));
     vmdispatch (GET_OPCODE(i)) {
       vmcase(OP_MOVE) {
         StkId ra = RA(i);
         setobjs2s(L, ra, RB(i));
         vmbreak;
       }
       vmcase(OP_LOADI) {
         StkId ra = RA(i);
         lua_Integer b = GETARG_sBx(i);
         setivalue(s2v(ra), b);
         vmbreak;
       }
       vmcase(OP_LOADF) {
         StkId ra = RA(i);
         int b = GETARG_sBx(i);
         setfltvalue(s2v(ra), cast_num(b));
         vmbreak;
       }
       vmcase(OP_LOADK) {
         StkId ra = RA(i);
         TValue *rb = k + GETARG_Bx(i);
         setobj2s(L, ra, rb);
         vmbreak;
       }
       vmcase(OP_LOADKX) {
         StkId ra = RA(i);
         TValue *rb;
         rb = k + GETARG_Ax(*pc); pc++;
         setobj2s(L, ra, rb);
         vmbreak;
       }
       vmcase(OP_LOADFALSE) {
         StkId ra = RA(i);
         setbfvalue(s2v(ra));
         vmbreak;
       }
       vmcase(OP_LFALSESKIP) {
         StkId ra = RA(i);
         setbfvalue(s2v(ra));
         pc++;  /* skip next instruction */
         vmbreak;
       }
       vmcase(OP_LOADTRUE) {
         StkId ra = RA(i);
         setbtvalue(s2v(ra));
         vmbreak;
       }
       vmcase(OP_LOADNIL) {
         StkId ra = RA(i);
         int b = GETARG_B(i);
         do {
           setnilvalue(s2v(ra++));
         } while (b--);
         vmbreak;
       }
       vmcase(OP_GETUPVAL) {
         StkId ra = RA(i);
         int b = GETARG_B(i);
         setobj2s(L, ra, cl->upvals[b]->v.p);
         vmbreak;
       }
       vmcase(OP_SETUPVAL) {
         StkId ra = RA(i);
         UpVal *uv = cl->upvals[GETARG_B(i)];
         setobj(L, uv->v.p, s2v(ra));
         luaC_barrier(L, uv, s2v(ra));
         vmbreak;
       }
       vmcase(OP_GETTABUP) {
         StkId ra = RA(i);
         TValue *upval = cl->upvals[GETARG_B(i)]->v.p;
         TValue *rc = KC(i);
         TString *key = tsvalue(rc);  /* key must be a short string */
         lu_byte tag;
         luaV_fastget(upval, key, s2v(ra), luaH_getshortstr, tag);
         if (tagisempty(tag))
           Protect(luaV_finishget(L, upval, rc, ra, tag));
         vmbreak;
       }
       vmcase(OP_GETTABLE) {
         StkId ra = RA(i);
         TValue *rb = vRB(i);
         TValue *rc = vRC(i);
         lu_byte tag;
         if (ttisinteger(rc)) {  /* fast track for integers? */
           luaV_fastgeti(rb, ivalue(rc), s2v(ra), tag);
         }
         else
           luaV_fastget(rb, rc, s2v(ra), luaH_get, tag);
         if (tagisempty(tag))
           Protect(luaV_finishget(L, rb, rc, ra, tag));
         vmbreak;
       }
       vmcase(OP_GETI) {
         StkId ra = RA(i);
         TValue *rb = vRB(i);
         int c = GETARG_C(i);
         lu_byte tag;
         luaV_fastgeti(rb, c, s2v(ra), tag);
         if (tagisempty(tag)) {
           TValue key;
           setivalue(&key, c);
           Protect(luaV_finishget(L, rb, &key, ra, tag));
         }
         vmbreak;
       }
       vmcase(OP_GETFIELD) {
         StkId ra = RA(i);
         TValue *rb = vRB(i);
         TValue *rc = KC(i);
         TString *key = tsvalue(rc);  /* key must be a short string */
         lu_byte tag;
         luaV_fastget(rb, key, s2v(ra), luaH_getshortstr, tag);
         if (tagisempty(tag))
           Protect(luaV_finishget(L, rb, rc, ra, tag));
         vmbreak;
       }
       vmcase(OP_SETTABUP) {
         int hres;
         TValue *upval = cl->upvals[GETARG_A(i)]->v.p;
         TValue *rb = KB(i);
         TValue *rc = RKC(i);
         TString *key = tsvalue(rb);  /* key must be a short string */
         luaV_fastset(upval, key, rc, hres, luaH_psetshortstr);
         if (hres == HOK)
           luaV_finishfastset(L, upval, rc);
         else
           Protect(luaV_finishset(L, upval, rb, rc, hres));
         vmbreak;
       }
       vmcase(OP_SETTABLE) {
         StkId ra = RA(i);
         int hres;
         TValue *rb = vRB(i);  /* key (table is in 'ra') */
         TValue *rc = RKC(i);  /* value */
         if (ttisinteger(rb)) {  /* fast track for integers? */
           luaV_fastseti(s2v(ra), ivalue(rb), rc, hres);
         }
         else {
           luaV_fastset(s2v(ra), rb, rc, hres, luaH_pset);
         }
         if (hres == HOK)
           luaV_finishfastset(L, s2v(ra), rc);
         else
           Protect(luaV_finishset(L, s2v(ra), rb, rc, hres));
         vmbreak;
       }
       vmcase(OP_SETI) {
         StkId ra = RA(i);
         int hres;
         int b = GETARG_B(i);
         TValue *rc = RKC(i);
         luaV_fastseti(s2v(ra), b, rc, hres);
         if (hres == HOK)
           luaV_finishfastset(L, s2v(ra), rc);
         else {
           TValue key;
           setivalue(&key, b);
           Protect(luaV_finishset(L, s2v(ra), &key, rc, hres));
         }
         vmbreak;
       }
       vmcase(OP_SETFIELD) {
         StkId ra = RA(i);
         int hres;
         TValue *rb = KB(i);
         TValue *rc = RKC(i);
         TString *key = tsvalue(rb);  /* key must be a short string */
         luaV_fastset(s2v(ra), key, rc, hres, luaH_psetshortstr);
         if (hres == HOK)
           luaV_finishfastset(L, s2v(ra), rc);
         else
           Protect(luaV_finishset(L, s2v(ra), rb, rc, hres));
         vmbreak;
       }
       vmcase(OP_NEWTABLE) {
         StkId ra = RA(i);
         unsigned b = cast_uint(GETARG_vB(i));  /* log2(hash size) + 1 */
         unsigned c = cast_uint(GETARG_vC(i));  /* array size */
         Table *t;
         if (b > 0)
           b = 1u << (b - 1);  /* hash size is 2^(b - 1) */
         if (TESTARG_k(i)) {  /* non-zero extra argument? */
           lua_assert(GETARG_Ax(*pc) != 0);
           /* add it to array size */
           c += cast_uint(GETARG_Ax(*pc)) * (MAXARG_vC + 1);
         }
         pc++;  /* skip extra argument */
         L->top.p = 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) {
         StkId ra = RA(i);
         lu_byte tag;
         TValue *rb = vRB(i);
         TValue *rc = KC(i);
         TString *key = tsvalue(rc);  /* key must be a short string */
         setobj2s(L, ra + 1, rb);
         luaV_fastget(rb, key, s2v(ra), luaH_getshortstr, tag);
         if (tagisempty(tag))
           Protect(luaV_finishget(L, rb, rc, ra, tag));
         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) {
         savestate(L, ci);  /* in case of division by 0 */
         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) {
         savestate(L, ci);  /* in case of division by 0 */
         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) {
         StkId ra = RA(i);
         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) {
         StkId ra = RA(i);
         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) {
         savestate(L, ci);  /* in case of division by 0 */
         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 */
         savestate(L, ci);  /* in case of division by 0 */
         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) {
         StkId ra = RA(i);
         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) {
         StkId ra = RA(i);
         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) {
         StkId ra = RA(i);
         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) {
         StkId ra = RA(i);
         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) {
         StkId ra = RA(i);
         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) {
         StkId ra = RA(i);
         TValue *rb = vRB(i);
         if (l_isfalse(rb))
           setbtvalue(s2v(ra));
         else
           setbfvalue(s2v(ra));
         vmbreak;
       }
       vmcase(OP_LEN) {
         StkId ra = RA(i);
         Protect(luaV_objlen(L, ra, vRB(i)));
         vmbreak;
       }
       vmcase(OP_CONCAT) {
         StkId ra = RA(i);
         int n = GETARG_B(i);  /* number of elements to concatenate */
         L->top.p = ra + n;  /* mark the end of concat operands */
         ProtectNT(luaV_concat(L, n));
         checkGC(L, L->top.p); /* 'luaV_concat' ensures correct top */
         vmbreak;
       }
       vmcase(OP_CLOSE) {
         StkId ra = RA(i);
         lua_assert(!GETARG_B(i));  /* 'close must be alive */
         Protect(luaF_close(L, ra, LUA_OK, 1));
         vmbreak;
       }
       vmcase(OP_TBC) {
         StkId ra = RA(i);
         /* create new to-be-closed upvalue */
         halfProtect(luaF_newtbcupval(L, ra));
         vmbreak;
       }
       vmcase(OP_JMP) {
         dojump(ci, i, 0);
         vmbreak;
       }
       vmcase(OP_EQ) {
         StkId ra = RA(i);
         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) {
         StkId ra = RA(i);
         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) {
         StkId ra = RA(i);
         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) {
         StkId ra = RA(i);
         int cond = !l_isfalse(s2v(ra));
         docondjump();
         vmbreak;
       }
       vmcase(OP_TESTSET) {
         StkId ra = RA(i);
         TValue *rb = vRB(i);
         if (l_isfalse(rb) == GETARG_k(i))
           pc++;
         else {
           setobj2s(L, ra, rb);
           donextjump(ci);
         }
         vmbreak;
       }
       vmcase(OP_CALL) {
         StkId ra = RA(i);
         CallInfo *newci;
         int b = GETARG_B(i);
         int nresults = GETARG_C(i) - 1;
         if (b != 0)  /* fixed number of arguments? */
           L->top.p = ra + b;  /* top signals number of arguments */
         /* else previous instruction set top */
         savepc(L);  /* in case of errors */
         if ((newci = luaD_precall(L, ra, nresults)) == NULL)
           updatetrap(ci);  /* C call; nothing else to be done */
         else {  /* Lua call: run function in this same C frame */
           ci = newci;
           goto startfunc;
         }
         vmbreak;
       }
       vmcase(OP_TAILCALL) {
         StkId ra = RA(i);
         int b = GETARG_B(i);  /* number of arguments + 1 (function) */
         int n;  /* number of results when calling a C function */
         int nparams1 = GETARG_C(i);
         /* delta is virtual 'func' - real 'func' (vararg functions) */
         int delta = (nparams1) ? ci->u.l.nextraargs + nparams1 : 0;
         if (b != 0)
           L->top.p = ra + b;
         else  /* previous instruction set top */
           b = cast_int(L->top.p - ra);
         savepc(ci);  /* several calls here can raise errors */
         if (TESTARG_k(i)) {
           luaF_closeupval(L, base);  /* close upvalues from current call */
           lua_assert(L->tbclist.p < base);  /* no pending tbc variables */
           lua_assert(base == ci->func.p + 1);
         }
         if ((n = luaD_pretailcall(L, ci, ra, b, delta)) < 0)  /* Lua function? */
           goto startfunc;  /* execute the callee */
         else {  /* C function? */
           ci->func.p -= delta;  /* restore 'func' (if vararg) */
           luaD_poscall(L, ci, n);  /* finish caller */
           updatetrap(ci);  /* 'luaD_poscall' can change hooks */
           goto ret;  /* caller returns after the tail call */
         }
       }
       vmcase(OP_RETURN) {
         StkId ra = RA(i);
         int n = GETARG_B(i) - 1;  /* number of results */
         int nparams1 = GETARG_C(i);
         if (n < 0)  /* not fixed? */
           n = cast_int(L->top.p - ra);  /* get what is available */
         savepc(ci);
         if (TESTARG_k(i)) {  /* may there be open upvalues? */
           ci->u2.nres = n;  /* save number of returns */
           if (L->top.p < ci->top.p)
             L->top.p = ci->top.p;
           luaF_close(L, base, CLOSEKTOP, 1);
           updatetrap(ci);
           updatestack(ci);
         }
         if (nparams1)  /* vararg function? */
           ci->func.p -= ci->u.l.nextraargs + nparams1;
         L->top.p = ra + n;  /* set call for 'luaD_poscall' */
         luaD_poscall(L, ci, n);
         updatetrap(ci);  /* 'luaD_poscall' can change hooks */
         goto ret;
       }
       vmcase(OP_RETURN0) {
         if (l_unlikely(L->hookmask)) {
           StkId ra = RA(i);
           L->top.p = ra;
           savepc(ci);
           luaD_poscall(L, ci, 0);  /* no hurry... */
           trap = 1;
         }
         else {  /* do the 'poscall' here */
           int nres = get_nresults(ci->callstatus);
           L->ci = ci->previous;  /* back to caller */
           L->top.p = base - 1;
           for (; l_unlikely(nres > 0); nres--)
             setnilvalue(s2v(L->top.p++));  /* all results are nil */
         }
         goto ret;
       }
       vmcase(OP_RETURN1) {
         if (l_unlikely(L->hookmask)) {
           StkId ra = RA(i);
           L->top.p = ra + 1;
           savepc(ci);
           luaD_poscall(L, ci, 1);  /* no hurry... */
           trap = 1;
         }
         else {  /* do the 'poscall' here */
           int nres = get_nresults(ci->callstatus);
           L->ci = ci->previous;  /* back to caller */
           if (nres == 0)
             L->top.p = base - 1;  /* asked for no results */
           else {
             StkId ra = RA(i);
             setobjs2s(L, base - 1, ra);  /* at least this result */
             L->top.p = base;
             for (; l_unlikely(nres > 1); nres--)
               setnilvalue(s2v(L->top.p++));  /* complete missing results */
           }
         }
        ret:  /* return from a Lua function */
         if (ci->callstatus & CIST_FRESH)
           return;  /* end this frame */
         else {
           ci = ci->previous;
           goto returning;  /* continue running caller in this frame */
         }
       }
       vmcase(OP_FORLOOP) {
         StkId ra = RA(i);
         if (ttisinteger(s2v(ra + 1))) {  /* integer loop? */
           lua_Unsigned count = l_castS2U(ivalue(s2v(ra)));
           if (count > 0) {  /* still more iterations? */
             lua_Integer step = ivalue(s2v(ra + 1));
             lua_Integer idx = ivalue(s2v(ra + 2));  /* control variable */
             chgivalue(s2v(ra), l_castU2S(count - 1));  /* update counter */
             idx = intop(+, idx, step);  /* add step to index */
             chgivalue(s2v(ra + 2), idx);  /* update 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) {
         StkId ra = RA(i);
         savestate(L, ci);  /* in case of errors */
         if (forprep(L, ra))
           pc += GETARG_Bx(i) + 1;  /* skip the loop */
         vmbreak;
       }
       vmcase(OP_TFORPREP) {
        /* before: 'ra' has the iterator function, 'ra + 1' has the state,
           'ra + 2' has the initial value for the control variable, and
           'ra + 3' has the closing variable. This opcode then swaps the
           control and the closing variables and marks the closing variable
           as to-be-closed.
        */
        StkId ra = RA(i);
        TValue temp;  /* to swap control and closing variables */
        setobj(L, &temp, s2v(ra + 3));
        setobjs2s(L, ra + 3, ra + 2);
        setobj2s(L, ra + 2, &temp);
         /* create to-be-closed upvalue (if closing var. is not nil) */
         halfProtect(luaF_newtbcupval(L, ra + 2));
         pc += GETARG_Bx(i);  /* go to end of the loop */
         i = *(pc++);  /* fetch 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 closing variable, and 'ra + 3' has the control
            variable. The call will use the stack starting at 'ra + 3',
            so that it preserves the first three values, and the first
            return will be the new value for the control variable.
         */
         StkId ra = RA(i);
         setobjs2s(L, ra + 5, ra + 3);  /* copy the control variable */
         setobjs2s(L, ra + 4, ra + 1);  /* copy state */
         setobjs2s(L, ra + 3, ra);  /* copy function */
         L->top.p = ra + 3 + 3;
         ProtectNT(luaD_call(L, ra + 3, 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: {
         StkId ra = RA(i);
         if (!ttisnil(s2v(ra + 3)))  /* continue loop? */
           pc -= GETARG_Bx(i);  /* jump back */
         vmbreak;
       }}
       vmcase(OP_SETLIST) {
         StkId ra = RA(i);
         unsigned n = cast_uint(GETARG_vB(i));
         unsigned int last = cast_uint(GETARG_vC(i));
         Table *h = hvalue(s2v(ra));
         if (n == 0)
           n = cast_uint(L->top.p - ra) - 1;  /* get up to the top */
         else
           L->top.p = ci->top.p;  /* correct top in case of emergency GC */
         last += n;
         if (TESTARG_k(i)) {
           last += cast_uint(GETARG_Ax(*pc)) * (MAXARG_vC + 1);
           pc++;
         }
         /* when 'n' is known, table should have proper size */
         if (last > h->asize) {  /* needs more space? */
           /* fixed-size sets should have space preallocated */
           lua_assert(GETARG_vB(i) == 0);
           luaH_resizearray(L, h, last);  /* preallocate it at once */
         }
         for (; n > 0; n--) {
           TValue *val = s2v(ra + n);
           obj2arr(h, last - 1, val);
           last--;
           luaC_barrierback(L, obj2gco(h), val);
         }
         vmbreak;
       }
       vmcase(OP_CLOSURE) {
         StkId ra = RA(i);
         Proto *p = cl->p->p[GETARG_Bx(i)];
         halfProtect(pushclosure(L, p, cl->upvals, base, ra));
         checkGC(L, ra + 1);
         vmbreak;
       }
       vmcase(OP_VARARG) {
         StkId ra = RA(i);
         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 (l_unlikely(trap)) {  /* previous "Protect" updated trap */
           luaD_hookcall(L, ci);
           L->oldpc = 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;
       }
     }
   }
 }
 
 /* }================================================================== */