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    1 /*
    2 ** $Id: lvm.c $
    3 ** Lua virtual machine
    4 ** See Copyright Notice in lua.h
    5 */
    6 
    7 #define lvm_c
    8 #define LUA_CORE
    9 
   10 #include "lprefix.h"
   11 
   12 #include <float.h>
   13 #include <limits.h>
   14 #include <math.h>
   15 #include <stdio.h>
   16 #include <stdlib.h>
   17 #include <string.h>
   18 
   19 #include "lua.h"
   20 
   21 #include "ldebug.h"
   22 #include "ldo.h"
   23 #include "lfunc.h"
   24 #include "lgc.h"
   25 #include "lobject.h"
   26 #include "lopcodes.h"
   27 #include "lstate.h"
   28 #include "lstring.h"
   29 #include "ltable.h"
   30 #include "ltm.h"
   31 #include "lvm.h"
   32 
   33 
   34 /*
   35 ** By default, use jump tables in the main interpreter loop on gcc
   36 ** and compatible compilers.
   37 */
   38 #if !defined(LUA_USE_JUMPTABLE)
   39 #if defined(__GNUC__)
   40 #define LUA_USE_JUMPTABLE   1
   41 #else
   42 #define LUA_USE_JUMPTABLE   0
   43 #endif
   44 #endif
   45 
   46 
   47 
   48 /* limit for table tag-method chains (to avoid infinite loops) */
   49 #define MAXTAGLOOP  2000
   50 
   51 
   52 /*
   53 ** 'l_intfitsf' checks whether a given integer is in the range that
   54 ** can be converted to a float without rounding. Used in comparisons.
   55 */
   56 
   57 /* number of bits in the mantissa of a float */
   58 #define NBM     (l_floatatt(MANT_DIG))
   59 
   60 /*
   61 ** Check whether some integers may not fit in a float, testing whether
   62 ** (maxinteger >> NBM) > 0. (That implies (1 << NBM) <= maxinteger.)
   63 ** (The shifts are done in parts, to avoid shifting by more than the size
   64 ** of an integer. In a worst case, NBM == 113 for long double and
   65 ** sizeof(long) == 32.)
   66 */
   67 #if ((((LUA_MAXINTEGER >> (NBM / 4)) >> (NBM / 4)) >> (NBM / 4)) \
   68     >> (NBM - (3 * (NBM / 4))))  >  0
   69 
   70 /* limit for integers that fit in a float */
   71 #define MAXINTFITSF ((lua_Unsigned)1 << NBM)
   72 
   73 /* check whether 'i' is in the interval [-MAXINTFITSF, MAXINTFITSF] */
   74 #define l_intfitsf(i)   ((MAXINTFITSF + l_castS2U(i)) <= (2 * MAXINTFITSF))
   75 
   76 #else  /* all integers fit in a float precisely */
   77 
   78 #define l_intfitsf(i)   1
   79 
   80 #endif
   81 
   82 
   83 /*
   84 ** Try to convert a value from string to a number value.
   85 ** If the value is not a string or is a string not representing
   86 ** a valid numeral (or if coercions from strings to numbers
   87 ** are disabled via macro 'cvt2num'), do not modify 'result'
   88 ** and return 0.
   89 */
   90 static int l_strton (const TValue *obj, TValue *result) {
   91   lua_assert(obj != result);
   92   if (!cvt2num(obj))  /* is object not a string? */
   93     return 0;
   94   else
   95     return (luaO_str2num(svalue(obj), result) == vslen(obj) + 1);
   96 }
   97 
   98 
   99 /*
  100 ** Try to convert a value to a float. The float case is already handled
  101 ** by the macro 'tonumber'.
  102 */
  103 int luaV_tonumber_ (const TValue *obj, lua_Number *n) {
  104   TValue v;
  105   if (ttisinteger(obj)) {
  106     *n = cast_num(ivalue(obj));
  107     return 1;
  108   }
  109   else if (l_strton(obj, &v)) {  /* string coercible to number? */
  110     *n = nvalue(&v);  /* convert result of 'luaO_str2num' to a float */
  111     return 1;
  112   }
  113   else
  114     return 0;  /* conversion failed */
  115 }
  116 
  117 
  118 /*
  119 ** try to convert a float to an integer, rounding according to 'mode'.
  120 */
  121 int luaV_flttointeger (lua_Number n, lua_Integer *p, F2Imod mode) {
  122   lua_Number f = l_floor(n);
  123   if (n != f) {  /* not an integral value? */
  124     if (mode == F2Ieq) return 0;  /* fails if mode demands integral value */
  125     else if (mode == F2Iceil)  /* needs ceil? */
  126       f += 1;  /* convert floor to ceil (remember: n != f) */
  127   }
  128   return lua_numbertointeger(f, p);
  129 }
  130 
  131 
  132 /*
  133 ** try to convert a value to an integer, rounding according to 'mode',
  134 ** without string coercion.
  135 ** ("Fast track" handled by macro 'tointegerns'.)
  136 */
  137 int luaV_tointegerns (const TValue *obj, lua_Integer *p, F2Imod mode) {
  138   if (ttisfloat(obj))
  139     return luaV_flttointeger(fltvalue(obj), p, mode);
  140   else if (ttisinteger(obj)) {
  141     *p = ivalue(obj);
  142     return 1;
  143   }
  144   else
  145     return 0;
  146 }
  147 
  148 
  149 /*
  150 ** try to convert a value to an integer.
  151 */
  152 int luaV_tointeger (const TValue *obj, lua_Integer *p, F2Imod mode) {
  153   TValue v;
  154   if (l_strton(obj, &v))  /* does 'obj' point to a numerical string? */
  155     obj = &v;  /* change it to point to its corresponding number */
  156   return luaV_tointegerns(obj, p, mode);
  157 }
  158 
  159 
  160 /*
  161 ** Try to convert a 'for' limit to an integer, preserving the semantics
  162 ** of the loop. Return true if the loop must not run; otherwise, '*p'
  163 ** gets the integer limit.
  164 ** (The following explanation assumes a positive step; it is valid for
  165 ** negative steps mutatis mutandis.)
  166 ** If the limit is an integer or can be converted to an integer,
  167 ** rounding down, that is the limit.
  168 ** Otherwise, check whether the limit can be converted to a float. If
  169 ** the float is too large, clip it to LUA_MAXINTEGER.  If the float
  170 ** is too negative, the loop should not run, because any initial
  171 ** integer value is greater than such limit; so, the function returns
  172 ** true to signal that. (For this latter case, no integer limit would be
  173 ** correct; even a limit of LUA_MININTEGER would run the loop once for
  174 ** an initial value equal to LUA_MININTEGER.)
  175 */
  176 static int forlimit (lua_State *L, lua_Integer init, const TValue *lim,
  177                                    lua_Integer *p, lua_Integer step) {
  178   if (!luaV_tointeger(lim, p, (step < 0 ? F2Iceil : F2Ifloor))) {
  179     /* not coercible to in integer */
  180     lua_Number flim;  /* try to convert to float */
  181     if (!tonumber(lim, &flim)) /* cannot convert to float? */
  182       luaG_forerror(L, lim, "limit");
  183     /* else 'flim' is a float out of integer bounds */
  184     if (luai_numlt(0, flim)) {  /* if it is positive, it is too large */
  185       if (step < 0) return 1;  /* initial value must be less than it */
  186       *p = LUA_MAXINTEGER;  /* truncate */
  187     }
  188     else {  /* it is less than min integer */
  189       if (step > 0) return 1;  /* initial value must be greater than it */
  190       *p = LUA_MININTEGER;  /* truncate */
  191     }
  192   }
  193   return (step > 0 ? init > *p : init < *p);  /* not to run? */
  194 }
  195 
  196 
  197 /*
  198 ** Prepare a numerical for loop (opcode OP_FORPREP).
  199 ** Return true to skip the loop. Otherwise,
  200 ** after preparation, stack will be as follows:
  201 **   ra : internal index (safe copy of the control variable)
  202 **   ra + 1 : loop counter (integer loops) or limit (float loops)
  203 **   ra + 2 : step
  204 **   ra + 3 : control variable
  205 */
  206 static int forprep (lua_State *L, StkId ra) {
  207   TValue *pinit = s2v(ra);
  208   TValue *plimit = s2v(ra + 1);
  209   TValue *pstep = s2v(ra + 2);
  210   if (ttisinteger(pinit) && ttisinteger(pstep)) { /* integer loop? */
  211     lua_Integer init = ivalue(pinit);
  212     lua_Integer step = ivalue(pstep);
  213     lua_Integer limit;
  214     if (step == 0)
  215       luaG_runerror(L, "'for' step is zero");
  216     setivalue(s2v(ra + 3), init);  /* control variable */
  217     if (forlimit(L, init, plimit, &limit, step))
  218       return 1;  /* skip the loop */
  219     else {  /* prepare loop counter */
  220       lua_Unsigned count;
  221       if (step > 0) {  /* ascending loop? */
  222         count = l_castS2U(limit) - l_castS2U(init);
  223         if (step != 1)  /* avoid division in the too common case */
  224           count /= l_castS2U(step);
  225       }
  226       else {  /* step < 0; descending loop */
  227         count = l_castS2U(init) - l_castS2U(limit);
  228         /* 'step+1' avoids negating 'mininteger' */
  229         count /= l_castS2U(-(step + 1)) + 1u;
  230       }
  231       /* store the counter in place of the limit (which won't be
  232          needed anymore) */
  233       setivalue(plimit, l_castU2S(count));
  234     }
  235   }
  236   else {  /* try making all values floats */
  237     lua_Number init; lua_Number limit; lua_Number step;
  238     if (l_unlikely(!tonumber(plimit, &limit)))
  239       luaG_forerror(L, plimit, "limit");
  240     if (l_unlikely(!tonumber(pstep, &step)))
  241       luaG_forerror(L, pstep, "step");
  242     if (l_unlikely(!tonumber(pinit, &init)))
  243       luaG_forerror(L, pinit, "initial value");
  244     if (step == 0)
  245       luaG_runerror(L, "'for' step is zero");
  246     if (luai_numlt(0, step) ? luai_numlt(limit, init)
  247                             : luai_numlt(init, limit))
  248       return 1;  /* skip the loop */
  249     else {
  250       /* make sure internal values are all floats */
  251       setfltvalue(plimit, limit);
  252       setfltvalue(pstep, step);
  253       setfltvalue(s2v(ra), init);  /* internal index */
  254       setfltvalue(s2v(ra + 3), init);  /* control variable */
  255     }
  256   }
  257   return 0;
  258 }
  259 
  260 
  261 /*
  262 ** Execute a step of a float numerical for loop, returning
  263 ** true iff the loop must continue. (The integer case is
  264 ** written online with opcode OP_FORLOOP, for performance.)
  265 */
  266 static int floatforloop (StkId ra) {
  267   lua_Number step = fltvalue(s2v(ra + 2));
  268   lua_Number limit = fltvalue(s2v(ra + 1));
  269   lua_Number idx = fltvalue(s2v(ra));  /* internal index */
  270   idx = luai_numadd(L, idx, step);  /* increment index */
  271   if (luai_numlt(0, step) ? luai_numle(idx, limit)
  272                           : luai_numle(limit, idx)) {
  273     chgfltvalue(s2v(ra), idx);  /* update internal index */
  274     setfltvalue(s2v(ra + 3), idx);  /* and control variable */
  275     return 1;  /* jump back */
  276   }
  277   else
  278     return 0;  /* finish the loop */
  279 }
  280 
  281 
  282 /*
  283 ** Finish the table access 'val = t[key]'.
  284 ** if 'slot' is NULL, 't' is not a table; otherwise, 'slot' points to
  285 ** t[k] entry (which must be empty).
  286 */
  287 void luaV_finishget (lua_State *L, const TValue *t, TValue *key, StkId val,
  288                       const TValue *slot) {
  289   int loop;  /* counter to avoid infinite loops */
  290   const TValue *tm;  /* metamethod */
  291   for (loop = 0; loop < MAXTAGLOOP; loop++) {
  292     if (slot == NULL) {  /* 't' is not a table? */
  293       lua_assert(!ttistable(t));
  294       tm = luaT_gettmbyobj(L, t, TM_INDEX);
  295       if (l_unlikely(notm(tm)))
  296         luaG_typeerror(L, t, "index");  /* no metamethod */
  297       /* else will try the metamethod */
  298     }
  299     else {  /* 't' is a table */
  300       lua_assert(isempty(slot));
  301       tm = fasttm(L, hvalue(t)->metatable, TM_INDEX);  /* table's metamethod */
  302       if (tm == NULL) {  /* no metamethod? */
  303         setnilvalue(s2v(val));  /* result is nil */
  304         return;
  305       }
  306       /* else will try the metamethod */
  307     }
  308     if (ttisfunction(tm)) {  /* is metamethod a function? */
  309       luaT_callTMres(L, tm, t, key, val);  /* call it */
  310       return;
  311     }
  312     t = tm;  /* else try to access 'tm[key]' */
  313     if (luaV_fastget(L, t, key, slot, luaH_get)) {  /* fast track? */
  314       setobj2s(L, val, slot);  /* done */
  315       return;
  316     }
  317     /* else repeat (tail call 'luaV_finishget') */
  318   }
  319   luaG_runerror(L, "'__index' chain too long; possible loop");
  320 }
  321 
  322 
  323 /*
  324 ** Finish a table assignment 't[key] = val'.
  325 ** If 'slot' is NULL, 't' is not a table.  Otherwise, 'slot' points
  326 ** to the entry 't[key]', or to a value with an absent key if there
  327 ** is no such entry.  (The value at 'slot' must be empty, otherwise
  328 ** 'luaV_fastget' would have done the job.)
  329 */
  330 void luaV_finishset (lua_State *L, const TValue *t, TValue *key,
  331                      TValue *val, const TValue *slot) {
  332   int loop;  /* counter to avoid infinite loops */
  333   for (loop = 0; loop < MAXTAGLOOP; loop++) {
  334     const TValue *tm;  /* '__newindex' metamethod */
  335     if (slot != NULL) {  /* is 't' a table? */
  336       Table *h = hvalue(t);  /* save 't' table */
  337       lua_assert(isempty(slot));  /* slot must be empty */
  338       tm = fasttm(L, h->metatable, TM_NEWINDEX);  /* get metamethod */
  339       if (tm == NULL) {  /* no metamethod? */
  340         luaH_finishset(L, h, key, slot, val);  /* set new value */
  341         invalidateTMcache(h);
  342         luaC_barrierback(L, obj2gco(h), val);
  343         return;
  344       }
  345       /* else will try the metamethod */
  346     }
  347     else {  /* not a table; check metamethod */
  348       tm = luaT_gettmbyobj(L, t, TM_NEWINDEX);
  349       if (l_unlikely(notm(tm)))
  350         luaG_typeerror(L, t, "index");
  351     }
  352     /* try the metamethod */
  353     if (ttisfunction(tm)) {
  354       luaT_callTM(L, tm, t, key, val);
  355       return;
  356     }
  357     t = tm;  /* else repeat assignment over 'tm' */
  358     if (luaV_fastget(L, t, key, slot, luaH_get)) {
  359       luaV_finishfastset(L, t, slot, val);
  360       return;  /* done */
  361     }
  362     /* else 'return luaV_finishset(L, t, key, val, slot)' (loop) */
  363   }
  364   luaG_runerror(L, "'__newindex' chain too long; possible loop");
  365 }
  366 
  367 
  368 /*
  369 ** Compare two strings 'ls' x 'rs', returning an integer less-equal-
  370 ** -greater than zero if 'ls' is less-equal-greater than 'rs'.
  371 ** The code is a little tricky because it allows '\0' in the strings
  372 ** and it uses 'strcoll' (to respect locales) for each segments
  373 ** of the strings.
  374 */
  375 static int l_strcmp (const TString *ls, const TString *rs) {
  376   const char *l = getstr(ls);
  377   size_t ll = tsslen(ls);
  378   const char *r = getstr(rs);
  379   size_t lr = tsslen(rs);
  380   for (;;) {  /* for each segment */
  381     int temp = strcoll(l, r);
  382     if (temp != 0)  /* not equal? */
  383       return temp;  /* done */
  384     else {  /* strings are equal up to a '\0' */
  385       size_t len = strlen(l);  /* index of first '\0' in both strings */
  386       if (len == lr)  /* 'rs' is finished? */
  387         return (len == ll) ? 0 : 1;  /* check 'ls' */
  388       else if (len == ll)  /* 'ls' is finished? */
  389         return -1;  /* 'ls' is less than 'rs' ('rs' is not finished) */
  390       /* both strings longer than 'len'; go on comparing after the '\0' */
  391       len++;
  392       l += len; ll -= len; r += len; lr -= len;
  393     }
  394   }
  395 }
  396 
  397 
  398 /*
  399 ** Check whether integer 'i' is less than float 'f'. If 'i' has an
  400 ** exact representation as a float ('l_intfitsf'), compare numbers as
  401 ** floats. Otherwise, use the equivalence 'i < f <=> i < ceil(f)'.
  402 ** If 'ceil(f)' is out of integer range, either 'f' is greater than
  403 ** all integers or less than all integers.
  404 ** (The test with 'l_intfitsf' is only for performance; the else
  405 ** case is correct for all values, but it is slow due to the conversion
  406 ** from float to int.)
  407 ** When 'f' is NaN, comparisons must result in false.
  408 */
  409 static int LTintfloat (lua_Integer i, lua_Number f) {
  410   if (l_intfitsf(i))
  411     return luai_numlt(cast_num(i), f);  /* compare them as floats */
  412   else {  /* i < f <=> i < ceil(f) */
  413     lua_Integer fi;
  414     if (luaV_flttointeger(f, &fi, F2Iceil))  /* fi = ceil(f) */
  415       return i < fi;   /* compare them as integers */
  416     else  /* 'f' is either greater or less than all integers */
  417       return f > 0;  /* greater? */
  418   }
  419 }
  420 
  421 
  422 /*
  423 ** Check whether integer 'i' is less than or equal to float 'f'.
  424 ** See comments on previous function.
  425 */
  426 static int LEintfloat (lua_Integer i, lua_Number f) {
  427   if (l_intfitsf(i))
  428     return luai_numle(cast_num(i), f);  /* compare them as floats */
  429   else {  /* i <= f <=> i <= floor(f) */
  430     lua_Integer fi;
  431     if (luaV_flttointeger(f, &fi, F2Ifloor))  /* fi = floor(f) */
  432       return i <= fi;   /* compare them as integers */
  433     else  /* 'f' is either greater or less than all integers */
  434       return f > 0;  /* greater? */
  435   }
  436 }
  437 
  438 
  439 /*
  440 ** Check whether float 'f' is less than integer 'i'.
  441 ** See comments on previous function.
  442 */
  443 static int LTfloatint (lua_Number f, lua_Integer i) {
  444   if (l_intfitsf(i))
  445     return luai_numlt(f, cast_num(i));  /* compare them as floats */
  446   else {  /* f < i <=> floor(f) < i */
  447     lua_Integer fi;
  448     if (luaV_flttointeger(f, &fi, F2Ifloor))  /* fi = floor(f) */
  449       return fi < i;   /* compare them as integers */
  450     else  /* 'f' is either greater or less than all integers */
  451       return f < 0;  /* less? */
  452   }
  453 }
  454 
  455 
  456 /*
  457 ** Check whether float 'f' is less than or equal to integer 'i'.
  458 ** See comments on previous function.
  459 */
  460 static int LEfloatint (lua_Number f, lua_Integer i) {
  461   if (l_intfitsf(i))
  462     return luai_numle(f, cast_num(i));  /* compare them as floats */
  463   else {  /* f <= i <=> ceil(f) <= i */
  464     lua_Integer fi;
  465     if (luaV_flttointeger(f, &fi, F2Iceil))  /* fi = ceil(f) */
  466       return fi <= i;   /* compare them as integers */
  467     else  /* 'f' is either greater or less than all integers */
  468       return f < 0;  /* less? */
  469   }
  470 }
  471 
  472 
  473 /*
  474 ** Return 'l < r', for numbers.
  475 */
  476 static int LTnum (const TValue *l, const TValue *r) {
  477   lua_assert(ttisnumber(l) && ttisnumber(r));
  478   if (ttisinteger(l)) {
  479     lua_Integer li = ivalue(l);
  480     if (ttisinteger(r))
  481       return li < ivalue(r);  /* both are integers */
  482     else  /* 'l' is int and 'r' is float */
  483       return LTintfloat(li, fltvalue(r));  /* l < r ? */
  484   }
  485   else {
  486     lua_Number lf = fltvalue(l);  /* 'l' must be float */
  487     if (ttisfloat(r))
  488       return luai_numlt(lf, fltvalue(r));  /* both are float */
  489     else  /* 'l' is float and 'r' is int */
  490       return LTfloatint(lf, ivalue(r));
  491   }
  492 }
  493 
  494 
  495 /*
  496 ** Return 'l <= r', for numbers.
  497 */
  498 static int LEnum (const TValue *l, const TValue *r) {
  499   lua_assert(ttisnumber(l) && ttisnumber(r));
  500   if (ttisinteger(l)) {
  501     lua_Integer li = ivalue(l);
  502     if (ttisinteger(r))
  503       return li <= ivalue(r);  /* both are integers */
  504     else  /* 'l' is int and 'r' is float */
  505       return LEintfloat(li, fltvalue(r));  /* l <= r ? */
  506   }
  507   else {
  508     lua_Number lf = fltvalue(l);  /* 'l' must be float */
  509     if (ttisfloat(r))
  510       return luai_numle(lf, fltvalue(r));  /* both are float */
  511     else  /* 'l' is float and 'r' is int */
  512       return LEfloatint(lf, ivalue(r));
  513   }
  514 }
  515 
  516 
  517 /*
  518 ** return 'l < r' for non-numbers.
  519 */
  520 static int lessthanothers (lua_State *L, const TValue *l, const TValue *r) {
  521   lua_assert(!ttisnumber(l) || !ttisnumber(r));
  522   if (ttisstring(l) && ttisstring(r))  /* both are strings? */
  523     return l_strcmp(tsvalue(l), tsvalue(r)) < 0;
  524   else
  525     return luaT_callorderTM(L, l, r, TM_LT);
  526 }
  527 
  528 
  529 /*
  530 ** Main operation less than; return 'l < r'.
  531 */
  532 int luaV_lessthan (lua_State *L, const TValue *l, const TValue *r) {
  533   if (ttisnumber(l) && ttisnumber(r))  /* both operands are numbers? */
  534     return LTnum(l, r);
  535   else return lessthanothers(L, l, r);
  536 }
  537 
  538 
  539 /*
  540 ** return 'l <= r' for non-numbers.
  541 */
  542 static int lessequalothers (lua_State *L, const TValue *l, const TValue *r) {
  543   lua_assert(!ttisnumber(l) || !ttisnumber(r));
  544   if (ttisstring(l) && ttisstring(r))  /* both are strings? */
  545     return l_strcmp(tsvalue(l), tsvalue(r)) <= 0;
  546   else
  547     return luaT_callorderTM(L, l, r, TM_LE);
  548 }
  549 
  550 
  551 /*
  552 ** Main operation less than or equal to; return 'l <= r'.
  553 */
  554 int luaV_lessequal (lua_State *L, const TValue *l, const TValue *r) {
  555   if (ttisnumber(l) && ttisnumber(r))  /* both operands are numbers? */
  556     return LEnum(l, r);
  557   else return lessequalothers(L, l, r);
  558 }
  559 
  560 
  561 /*
  562 ** Main operation for equality of Lua values; return 't1 == t2'.
  563 ** L == NULL means raw equality (no metamethods)
  564 */
  565 int luaV_equalobj (lua_State *L, const TValue *t1, const TValue *t2) {
  566   const TValue *tm;
  567   if (ttypetag(t1) != ttypetag(t2)) {  /* not the same variant? */
  568     if (ttype(t1) != ttype(t2) || ttype(t1) != LUA_TNUMBER)
  569       return 0;  /* only numbers can be equal with different variants */
  570     else {  /* two numbers with different variants */
  571       /* One of them is an integer. If the other does not have an
  572          integer value, they cannot be equal; otherwise, compare their
  573          integer values. */
  574       lua_Integer i1, i2;
  575       return (luaV_tointegerns(t1, &i1, F2Ieq) &&
  576               luaV_tointegerns(t2, &i2, F2Ieq) &&
  577               i1 == i2);
  578     }
  579   }
  580   /* values have same type and same variant */
  581   switch (ttypetag(t1)) {
  582     case LUA_VNIL: case LUA_VFALSE: case LUA_VTRUE: return 1;
  583     case LUA_VNUMINT: return (ivalue(t1) == ivalue(t2));
  584     case LUA_VNUMFLT: return luai_numeq(fltvalue(t1), fltvalue(t2));
  585     case LUA_VLIGHTUSERDATA: return pvalue(t1) == pvalue(t2);
  586     case LUA_VLCF: return fvalue(t1) == fvalue(t2);
  587     case LUA_VSHRSTR: return eqshrstr(tsvalue(t1), tsvalue(t2));
  588     case LUA_VLNGSTR: return luaS_eqlngstr(tsvalue(t1), tsvalue(t2));
  589     case LUA_VUSERDATA: {
  590       if (uvalue(t1) == uvalue(t2)) return 1;
  591       else if (L == NULL) return 0;
  592       tm = fasttm(L, uvalue(t1)->metatable, TM_EQ);
  593       if (tm == NULL)
  594         tm = fasttm(L, uvalue(t2)->metatable, TM_EQ);
  595       break;  /* will try TM */
  596     }
  597     case LUA_VTABLE: {
  598       if (hvalue(t1) == hvalue(t2)) return 1;
  599       else if (L == NULL) return 0;
  600       tm = fasttm(L, hvalue(t1)->metatable, TM_EQ);
  601       if (tm == NULL)
  602         tm = fasttm(L, hvalue(t2)->metatable, TM_EQ);
  603       break;  /* will try TM */
  604     }
  605     default:
  606       return gcvalue(t1) == gcvalue(t2);
  607   }
  608   if (tm == NULL)  /* no TM? */
  609     return 0;  /* objects are different */
  610   else {
  611     luaT_callTMres(L, tm, t1, t2, L->top);  /* call TM */
  612     return !l_isfalse(s2v(L->top));
  613   }
  614 }
  615 
  616 
  617 /* macro used by 'luaV_concat' to ensure that element at 'o' is a string */
  618 #define tostring(L,o)  \
  619     (ttisstring(o) || (cvt2str(o) && (luaO_tostring(L, o), 1)))
  620 
  621 #define isemptystr(o)   (ttisshrstring(o) && tsvalue(o)->shrlen == 0)
  622 
  623 /* copy strings in stack from top - n up to top - 1 to buffer */
  624 static void copy2buff (StkId top, int n, char *buff) {
  625   size_t tl = 0;  /* size already copied */
  626   do {
  627     size_t l = vslen(s2v(top - n));  /* length of string being copied */
  628     memcpy(buff + tl, svalue(s2v(top - n)), l * sizeof(char));
  629     tl += l;
  630   } while (--n > 0);
  631 }
  632 
  633 
  634 /*
  635 ** Main operation for concatenation: concat 'total' values in the stack,
  636 ** from 'L->top - total' up to 'L->top - 1'.
  637 */
  638 void luaV_concat (lua_State *L, int total) {
  639   if (total == 1)
  640     return;  /* "all" values already concatenated */
  641   do {
  642     StkId top = L->top;
  643     int n = 2;  /* number of elements handled in this pass (at least 2) */
  644     if (!(ttisstring(s2v(top - 2)) || cvt2str(s2v(top - 2))) ||
  645         !tostring(L, s2v(top - 1)))
  646       luaT_tryconcatTM(L);
  647     else if (isemptystr(s2v(top - 1)))  /* second operand is empty? */
  648       cast_void(tostring(L, s2v(top - 2)));  /* result is first operand */
  649     else if (isemptystr(s2v(top - 2))) {  /* first operand is empty string? */
  650       setobjs2s(L, top - 2, top - 1);  /* result is second op. */
  651     }
  652     else {
  653       /* at least two non-empty string values; get as many as possible */
  654       size_t tl = vslen(s2v(top - 1));
  655       TString *ts;
  656       /* collect total length and number of strings */
  657       for (n = 1; n < total && tostring(L, s2v(top - n - 1)); n++) {
  658         size_t l = vslen(s2v(top - n - 1));
  659         if (l_unlikely(l >= (MAX_SIZE/sizeof(char)) - tl))
  660           luaG_runerror(L, "string length overflow");
  661         tl += l;
  662       }
  663       if (tl <= LUAI_MAXSHORTLEN) {  /* is result a short string? */
  664         char buff[LUAI_MAXSHORTLEN];
  665         copy2buff(top, n, buff);  /* copy strings to buffer */
  666         ts = luaS_newlstr(L, buff, tl);
  667       }
  668       else {  /* long string; copy strings directly to final result */
  669         ts = luaS_createlngstrobj(L, tl);
  670         copy2buff(top, n, getstr(ts));
  671       }
  672       setsvalue2s(L, top - n, ts);  /* create result */
  673     }
  674     total -= n-1;  /* got 'n' strings to create 1 new */
  675     L->top -= n-1;  /* popped 'n' strings and pushed one */
  676   } while (total > 1);  /* repeat until only 1 result left */
  677 }
  678 
  679 
  680 /*
  681 ** Main operation 'ra = #rb'.
  682 */
  683 void luaV_objlen (lua_State *L, StkId ra, const TValue *rb) {
  684   const TValue *tm;
  685   switch (ttypetag(rb)) {
  686     case LUA_VTABLE: {
  687       Table *h = hvalue(rb);
  688       tm = fasttm(L, h->metatable, TM_LEN);
  689       if (tm) break;  /* metamethod? break switch to call it */
  690       setivalue(s2v(ra), luaH_getn(h));  /* else primitive len */
  691       return;
  692     }
  693     case LUA_VSHRSTR: {
  694       setivalue(s2v(ra), tsvalue(rb)->shrlen);
  695       return;
  696     }
  697     case LUA_VLNGSTR: {
  698       setivalue(s2v(ra), tsvalue(rb)->u.lnglen);
  699       return;
  700     }
  701     default: {  /* try metamethod */
  702       tm = luaT_gettmbyobj(L, rb, TM_LEN);
  703       if (l_unlikely(notm(tm)))  /* no metamethod? */
  704         luaG_typeerror(L, rb, "get length of");
  705       break;
  706     }
  707   }
  708   luaT_callTMres(L, tm, rb, rb, ra);
  709 }
  710 
  711 
  712 /*
  713 ** Integer division; return 'm // n', that is, floor(m/n).
  714 ** C division truncates its result (rounds towards zero).
  715 ** 'floor(q) == trunc(q)' when 'q >= 0' or when 'q' is integer,
  716 ** otherwise 'floor(q) == trunc(q) - 1'.
  717 */
  718 lua_Integer luaV_idiv (lua_State *L, lua_Integer m, lua_Integer n) {
  719   if (l_unlikely(l_castS2U(n) + 1u <= 1u)) {  /* special cases: -1 or 0 */
  720     if (n == 0)
  721       luaG_runerror(L, "attempt to divide by zero");
  722     return intop(-, 0, m);   /* n==-1; avoid overflow with 0x80000...//-1 */
  723   }
  724   else {
  725     lua_Integer q = m / n;  /* perform C division */
  726     if ((m ^ n) < 0 && m % n != 0)  /* 'm/n' would be negative non-integer? */
  727       q -= 1;  /* correct result for different rounding */
  728     return q;
  729   }
  730 }
  731 
  732 
  733 /*
  734 ** Integer modulus; return 'm % n'. (Assume that C '%' with
  735 ** negative operands follows C99 behavior. See previous comment
  736 ** about luaV_idiv.)
  737 */
  738 lua_Integer luaV_mod (lua_State *L, lua_Integer m, lua_Integer n) {
  739   if (l_unlikely(l_castS2U(n) + 1u <= 1u)) {  /* special cases: -1 or 0 */
  740     if (n == 0)
  741       luaG_runerror(L, "attempt to perform 'n%%0'");
  742     return 0;   /* m % -1 == 0; avoid overflow with 0x80000...%-1 */
  743   }
  744   else {
  745     lua_Integer r = m % n;
  746     if (r != 0 && (r ^ n) < 0)  /* 'm/n' would be non-integer negative? */
  747       r += n;  /* correct result for different rounding */
  748     return r;
  749   }
  750 }
  751 
  752 
  753 /*
  754 ** Float modulus
  755 */
  756 lua_Number luaV_modf (lua_State *L, lua_Number m, lua_Number n) {
  757   lua_Number r;
  758   luai_nummod(L, m, n, r);
  759   return r;
  760 }
  761 
  762 
  763 /* number of bits in an integer */
  764 #define NBITS   cast_int(sizeof(lua_Integer) * CHAR_BIT)
  765 
  766 /*
  767 ** Shift left operation. (Shift right just negates 'y'.)
  768 */
  769 #define luaV_shiftr(x,y)    luaV_shiftl(x,-(y))
  770 
  771 lua_Integer luaV_shiftl (lua_Integer x, lua_Integer y) {
  772   if (y < 0) {  /* shift right? */
  773     if (y <= -NBITS) return 0;
  774     else return intop(>>, x, -y);
  775   }
  776   else {  /* shift left */
  777     if (y >= NBITS) return 0;
  778     else return intop(<<, x, y);
  779   }
  780 }
  781 
  782 
  783 /*
  784 ** create a new Lua closure, push it in the stack, and initialize
  785 ** its upvalues.
  786 */
  787 static void pushclosure (lua_State *L, Proto *p, UpVal **encup, StkId base,
  788                          StkId ra) {
  789   int nup = p->sizeupvalues;
  790   Upvaldesc *uv = p->upvalues;
  791   int i;
  792   LClosure *ncl = luaF_newLclosure(L, nup);
  793   ncl->p = p;
  794   setclLvalue2s(L, ra, ncl);  /* anchor new closure in stack */
  795   for (i = 0; i < nup; i++) {  /* fill in its upvalues */
  796     if (uv[i].instack)  /* upvalue refers to local variable? */
  797       ncl->upvals[i] = luaF_findupval(L, base + uv[i].idx);
  798     else  /* get upvalue from enclosing function */
  799       ncl->upvals[i] = encup[uv[i].idx];
  800     luaC_objbarrier(L, ncl, ncl->upvals[i]);
  801   }
  802 }
  803 
  804 
  805 /*
  806 ** finish execution of an opcode interrupted by a yield
  807 */
  808 void luaV_finishOp (lua_State *L) {
  809   CallInfo *ci = L->ci;
  810   StkId base = ci->func + 1;
  811   Instruction inst = *(ci->u.l.savedpc - 1);  /* interrupted instruction */
  812   OpCode op = GET_OPCODE(inst);
  813   switch (op) {  /* finish its execution */
  814     case OP_MMBIN: case OP_MMBINI: case OP_MMBINK: {
  815       setobjs2s(L, base + GETARG_A(*(ci->u.l.savedpc - 2)), --L->top);
  816       break;
  817     }
  818     case OP_UNM: case OP_BNOT: case OP_LEN:
  819     case OP_GETTABUP: case OP_GETTABLE: case OP_GETI:
  820     case OP_GETFIELD: case OP_SELF: {
  821       setobjs2s(L, base + GETARG_A(inst), --L->top);
  822       break;
  823     }
  824     case OP_LT: case OP_LE:
  825     case OP_LTI: case OP_LEI:
  826     case OP_GTI: case OP_GEI:
  827     case OP_EQ: {  /* note that 'OP_EQI'/'OP_EQK' cannot yield */
  828       int res = !l_isfalse(s2v(L->top - 1));
  829       L->top--;
  830 #if defined(LUA_COMPAT_LT_LE)
  831       if (ci->callstatus & CIST_LEQ) {  /* "<=" using "<" instead? */
  832         ci->callstatus ^= CIST_LEQ;  /* clear mark */
  833         res = !res;  /* negate result */
  834       }
  835 #endif
  836       lua_assert(GET_OPCODE(*ci->u.l.savedpc) == OP_JMP);
  837       if (res != GETARG_k(inst))  /* condition failed? */
  838         ci->u.l.savedpc++;  /* skip jump instruction */
  839       break;
  840     }
  841     case OP_CONCAT: {
  842       StkId top = L->top - 1;  /* top when 'luaT_tryconcatTM' was called */
  843       int a = GETARG_A(inst);      /* first element to concatenate */
  844       int total = cast_int(top - 1 - (base + a));  /* yet to concatenate */
  845       setobjs2s(L, top - 2, top);  /* put TM result in proper position */
  846       L->top = top - 1;  /* top is one after last element (at top-2) */
  847       luaV_concat(L, total);  /* concat them (may yield again) */
  848       break;
  849     }
  850     case OP_CLOSE:  case OP_RETURN: {  /* yielded closing variables */
  851       ci->u.l.savedpc--;  /* repeat instruction to close other vars. */
  852       break;
  853     }
  854     default: {
  855       /* only these other opcodes can yield */
  856       lua_assert(op == OP_TFORCALL || op == OP_CALL ||
  857            op == OP_TAILCALL || op == OP_SETTABUP || op == OP_SETTABLE ||
  858            op == OP_SETI || op == OP_SETFIELD);
  859       break;
  860     }
  861   }
  862 }
  863 
  864 
  865 
  866 
  867 /*
  868 ** {==================================================================
  869 ** Macros for arithmetic/bitwise/comparison opcodes in 'luaV_execute'
  870 ** ===================================================================
  871 */
  872 
  873 #define l_addi(L,a,b)   intop(+, a, b)
  874 #define l_subi(L,a,b)   intop(-, a, b)
  875 #define l_muli(L,a,b)   intop(*, a, b)
  876 #define l_band(a,b) intop(&, a, b)
  877 #define l_bor(a,b)  intop(|, a, b)
  878 #define l_bxor(a,b) intop(^, a, b)
  879 
  880 #define l_lti(a,b)  (a < b)
  881 #define l_lei(a,b)  (a <= b)
  882 #define l_gti(a,b)  (a > b)
  883 #define l_gei(a,b)  (a >= b)
  884 
  885 
  886 /*
  887 ** Arithmetic operations with immediate operands. 'iop' is the integer
  888 ** operation, 'fop' is the float operation.
  889 */
  890 #define op_arithI(L,iop,fop) {  \
  891   TValue *v1 = vRB(i);  \
  892   int imm = GETARG_sC(i);  \
  893   if (ttisinteger(v1)) {  \
  894     lua_Integer iv1 = ivalue(v1);  \
  895     pc++; setivalue(s2v(ra), iop(L, iv1, imm));  \
  896   }  \
  897   else if (ttisfloat(v1)) {  \
  898     lua_Number nb = fltvalue(v1);  \
  899     lua_Number fimm = cast_num(imm);  \
  900     pc++; setfltvalue(s2v(ra), fop(L, nb, fimm)); \
  901   }}
  902 
  903 
  904 /*
  905 ** Auxiliary function for arithmetic operations over floats and others
  906 ** with two register operands.
  907 */
  908 #define op_arithf_aux(L,v1,v2,fop) {  \
  909   lua_Number n1; lua_Number n2;  \
  910   if (tonumberns(v1, n1) && tonumberns(v2, n2)) {  \
  911     pc++; setfltvalue(s2v(ra), fop(L, n1, n2));  \
  912   }}
  913 
  914 
  915 /*
  916 ** Arithmetic operations over floats and others with register operands.
  917 */
  918 #define op_arithf(L,fop) {  \
  919   TValue *v1 = vRB(i);  \
  920   TValue *v2 = vRC(i);  \
  921   op_arithf_aux(L, v1, v2, fop); }
  922 
  923 
  924 /*
  925 ** Arithmetic operations with K operands for floats.
  926 */
  927 #define op_arithfK(L,fop) {  \
  928   TValue *v1 = vRB(i);  \
  929   TValue *v2 = KC(i); lua_assert(ttisnumber(v2));  \
  930   op_arithf_aux(L, v1, v2, fop); }
  931 
  932 
  933 /*
  934 ** Arithmetic operations over integers and floats.
  935 */
  936 #define op_arith_aux(L,v1,v2,iop,fop) {  \
  937   if (ttisinteger(v1) && ttisinteger(v2)) {  \
  938     lua_Integer i1 = ivalue(v1); lua_Integer i2 = ivalue(v2);  \
  939     pc++; setivalue(s2v(ra), iop(L, i1, i2));  \
  940   }  \
  941   else op_arithf_aux(L, v1, v2, fop); }
  942 
  943 
  944 /*
  945 ** Arithmetic operations with register operands.
  946 */
  947 #define op_arith(L,iop,fop) {  \
  948   TValue *v1 = vRB(i);  \
  949   TValue *v2 = vRC(i);  \
  950   op_arith_aux(L, v1, v2, iop, fop); }
  951 
  952 
  953 /*
  954 ** Arithmetic operations with K operands.
  955 */
  956 #define op_arithK(L,iop,fop) {  \
  957   TValue *v1 = vRB(i);  \
  958   TValue *v2 = KC(i); lua_assert(ttisnumber(v2));  \
  959   op_arith_aux(L, v1, v2, iop, fop); }
  960 
  961 
  962 /*
  963 ** Bitwise operations with constant operand.
  964 */
  965 #define op_bitwiseK(L,op) {  \
  966   TValue *v1 = vRB(i);  \
  967   TValue *v2 = KC(i);  \
  968   lua_Integer i1;  \
  969   lua_Integer i2 = ivalue(v2);  \
  970   if (tointegerns(v1, &i1)) {  \
  971     pc++; setivalue(s2v(ra), op(i1, i2));  \
  972   }}
  973 
  974 
  975 /*
  976 ** Bitwise operations with register operands.
  977 */
  978 #define op_bitwise(L,op) {  \
  979   TValue *v1 = vRB(i);  \
  980   TValue *v2 = vRC(i);  \
  981   lua_Integer i1; lua_Integer i2;  \
  982   if (tointegerns(v1, &i1) && tointegerns(v2, &i2)) {  \
  983     pc++; setivalue(s2v(ra), op(i1, i2));  \
  984   }}
  985 
  986 
  987 /*
  988 ** Order operations with register operands. 'opn' actually works
  989 ** for all numbers, but the fast track improves performance for
  990 ** integers.
  991 */
  992 #define op_order(L,opi,opn,other) {  \
  993         int cond;  \
  994         TValue *rb = vRB(i);  \
  995         if (ttisinteger(s2v(ra)) && ttisinteger(rb)) {  \
  996           lua_Integer ia = ivalue(s2v(ra));  \
  997           lua_Integer ib = ivalue(rb);  \
  998           cond = opi(ia, ib);  \
  999         }  \
 1000         else if (ttisnumber(s2v(ra)) && ttisnumber(rb))  \
 1001           cond = opn(s2v(ra), rb);  \
 1002         else  \
 1003           Protect(cond = other(L, s2v(ra), rb));  \
 1004         docondjump(); }
 1005 
 1006 
 1007 /*
 1008 ** Order operations with immediate operand. (Immediate operand is
 1009 ** always small enough to have an exact representation as a float.)
 1010 */
 1011 #define op_orderI(L,opi,opf,inv,tm) {  \
 1012         int cond;  \
 1013         int im = GETARG_sB(i);  \
 1014         if (ttisinteger(s2v(ra)))  \
 1015           cond = opi(ivalue(s2v(ra)), im);  \
 1016         else if (ttisfloat(s2v(ra))) {  \
 1017           lua_Number fa = fltvalue(s2v(ra));  \
 1018           lua_Number fim = cast_num(im);  \
 1019           cond = opf(fa, fim);  \
 1020         }  \
 1021         else {  \
 1022           int isf = GETARG_C(i);  \
 1023           Protect(cond = luaT_callorderiTM(L, s2v(ra), im, inv, isf, tm));  \
 1024         }  \
 1025         docondjump(); }
 1026 
 1027 /* }================================================================== */
 1028 
 1029 
 1030 /*
 1031 ** {==================================================================
 1032 ** Function 'luaV_execute': main interpreter loop
 1033 ** ===================================================================
 1034 */
 1035 
 1036 /*
 1037 ** some macros for common tasks in 'luaV_execute'
 1038 */
 1039 
 1040 
 1041 #define RA(i)   (base+GETARG_A(i))
 1042 #define RB(i)   (base+GETARG_B(i))
 1043 #define vRB(i)  s2v(RB(i))
 1044 #define KB(i)   (k+GETARG_B(i))
 1045 #define RC(i)   (base+GETARG_C(i))
 1046 #define vRC(i)  s2v(RC(i))
 1047 #define KC(i)   (k+GETARG_C(i))
 1048 #define RKC(i)  ((TESTARG_k(i)) ? k + GETARG_C(i) : s2v(base + GETARG_C(i)))
 1049 
 1050 
 1051 
 1052 #define updatetrap(ci)  (trap = ci->u.l.trap)
 1053 
 1054 #define updatebase(ci)  (base = ci->func + 1)
 1055 
 1056 
 1057 #define updatestack(ci)  \
 1058     { if (l_unlikely(trap)) { updatebase(ci); ra = RA(i); } }
 1059 
 1060 
 1061 /*
 1062 ** Execute a jump instruction. The 'updatetrap' allows signals to stop
 1063 ** tight loops. (Without it, the local copy of 'trap' could never change.)
 1064 */
 1065 #define dojump(ci,i,e)  { pc += GETARG_sJ(i) + e; updatetrap(ci); }
 1066 
 1067 
 1068 /* for test instructions, execute the jump instruction that follows it */
 1069 #define donextjump(ci)  { Instruction ni = *pc; dojump(ci, ni, 1); }
 1070 
 1071 /*
 1072 ** do a conditional jump: skip next instruction if 'cond' is not what
 1073 ** was expected (parameter 'k'), else do next instruction, which must
 1074 ** be a jump.
 1075 */
 1076 #define docondjump()    if (cond != GETARG_k(i)) pc++; else donextjump(ci);
 1077 
 1078 
 1079 /*
 1080 ** Correct global 'pc'.
 1081 */
 1082 #define savepc(L)   (ci->u.l.savedpc = pc)
 1083 
 1084 
 1085 /*
 1086 ** Whenever code can raise errors, the global 'pc' and the global
 1087 ** 'top' must be correct to report occasional errors.
 1088 */
 1089 #define savestate(L,ci)     (savepc(L), L->top = ci->top)
 1090 
 1091 
 1092 /*
 1093 ** Protect code that, in general, can raise errors, reallocate the
 1094 ** stack, and change the hooks.
 1095 */
 1096 #define Protect(exp)  (savestate(L,ci), (exp), updatetrap(ci))
 1097 
 1098 /* special version that does not change the top */
 1099 #define ProtectNT(exp)  (savepc(L), (exp), updatetrap(ci))
 1100 
 1101 /*
 1102 ** Protect code that can only raise errors. (That is, it cannnot change
 1103 ** the stack or hooks.)
 1104 */
 1105 #define halfProtect(exp)  (savestate(L,ci), (exp))
 1106 
 1107 /* 'c' is the limit of live values in the stack */
 1108 #define checkGC(L,c)  \
 1109     { luaC_condGC(L, (savepc(L), L->top = (c)), \
 1110                          updatetrap(ci)); \
 1111            luai_threadyield(L); }
 1112 
 1113 
 1114 /* fetch an instruction and prepare its execution */
 1115 #define vmfetch()   { \
 1116   if (l_unlikely(trap)) {  /* stack reallocation or hooks? */ \
 1117     trap = luaG_traceexec(L, pc);  /* handle hooks */ \
 1118     updatebase(ci);  /* correct stack */ \
 1119   } \
 1120   i = *(pc++); \
 1121   ra = RA(i); /* WARNING: any stack reallocation invalidates 'ra' */ \
 1122 }
 1123 
 1124 #define vmdispatch(o)   switch(o)
 1125 #define vmcase(l)   case l:
 1126 #define vmbreak     break
 1127 
 1128 
 1129 void luaV_execute (lua_State *L, CallInfo *ci) {
 1130   LClosure *cl;
 1131   TValue *k;
 1132   StkId base;
 1133   const Instruction *pc;
 1134   int trap;
 1135 #if LUA_USE_JUMPTABLE
 1136 #include "ljumptab.h"
 1137 #endif
 1138  startfunc:
 1139   trap = L->hookmask;
 1140  returning:  /* trap already set */
 1141   cl = clLvalue(s2v(ci->func));
 1142   k = cl->p->k;
 1143   pc = ci->u.l.savedpc;
 1144   if (l_unlikely(trap)) {
 1145     if (pc == cl->p->code) {  /* first instruction (not resuming)? */
 1146       if (cl->p->is_vararg)
 1147         trap = 0;  /* hooks will start after VARARGPREP instruction */
 1148       else  /* check 'call' hook */
 1149         luaD_hookcall(L, ci);
 1150     }
 1151     ci->u.l.trap = 1;  /* assume trap is on, for now */
 1152   }
 1153   base = ci->func + 1;
 1154   /* main loop of interpreter */
 1155   for (;;) {
 1156     Instruction i;  /* instruction being executed */
 1157     StkId ra;  /* instruction's A register */
 1158     vmfetch();
 1159 // low-level line tracing for debugging Lua
 1160 // printf("line: %d\n", luaG_getfuncline(cl->p, pcRel(pc, cl->p)));
 1161     lua_assert(base == ci->func + 1);
 1162     lua_assert(base <= L->top && L->top < L->stack_last);
 1163     /* invalidate top for instructions not expecting it */
 1164     lua_assert(isIT(i) || (cast_void(L->top = base), 1));
 1165     vmdispatch (GET_OPCODE(i)) {
 1166       vmcase(OP_MOVE) {
 1167         setobjs2s(L, ra, RB(i));
 1168         vmbreak;
 1169       }
 1170       vmcase(OP_LOADI) {
 1171         lua_Integer b = GETARG_sBx(i);
 1172         setivalue(s2v(ra), b);
 1173         vmbreak;
 1174       }
 1175       vmcase(OP_LOADF) {
 1176         int b = GETARG_sBx(i);
 1177         setfltvalue(s2v(ra), cast_num(b));
 1178         vmbreak;
 1179       }
 1180       vmcase(OP_LOADK) {
 1181         TValue *rb = k + GETARG_Bx(i);
 1182         setobj2s(L, ra, rb);
 1183         vmbreak;
 1184       }
 1185       vmcase(OP_LOADKX) {
 1186         TValue *rb;
 1187         rb = k + GETARG_Ax(*pc); pc++;
 1188         setobj2s(L, ra, rb);
 1189         vmbreak;
 1190       }
 1191       vmcase(OP_LOADFALSE) {
 1192         setbfvalue(s2v(ra));
 1193         vmbreak;
 1194       }
 1195       vmcase(OP_LFALSESKIP) {
 1196         setbfvalue(s2v(ra));
 1197         pc++;  /* skip next instruction */
 1198         vmbreak;
 1199       }
 1200       vmcase(OP_LOADTRUE) {
 1201         setbtvalue(s2v(ra));
 1202         vmbreak;
 1203       }
 1204       vmcase(OP_LOADNIL) {
 1205         int b = GETARG_B(i);
 1206         do {
 1207           setnilvalue(s2v(ra++));
 1208         } while (b--);
 1209         vmbreak;
 1210       }
 1211       vmcase(OP_GETUPVAL) {
 1212         int b = GETARG_B(i);
 1213         setobj2s(L, ra, cl->upvals[b]->v);
 1214         vmbreak;
 1215       }
 1216       vmcase(OP_SETUPVAL) {
 1217         UpVal *uv = cl->upvals[GETARG_B(i)];
 1218         setobj(L, uv->v, s2v(ra));
 1219         luaC_barrier(L, uv, s2v(ra));
 1220         vmbreak;
 1221       }
 1222       vmcase(OP_GETTABUP) {
 1223         const TValue *slot;
 1224         TValue *upval = cl->upvals[GETARG_B(i)]->v;
 1225         TValue *rc = KC(i);
 1226         TString *key = tsvalue(rc);  /* key must be a string */
 1227         if (luaV_fastget(L, upval, key, slot, luaH_getshortstr)) {
 1228           setobj2s(L, ra, slot);
 1229         }
 1230         else
 1231           Protect(luaV_finishget(L, upval, rc, ra, slot));
 1232         vmbreak;
 1233       }
 1234       vmcase(OP_GETTABLE) {
 1235         const TValue *slot;
 1236         TValue *rb = vRB(i);
 1237         TValue *rc = vRC(i);
 1238         lua_Unsigned n;
 1239         if (ttisinteger(rc)  /* fast track for integers? */
 1240             ? (cast_void(n = ivalue(rc)), luaV_fastgeti(L, rb, n, slot))
 1241             : luaV_fastget(L, rb, rc, slot, luaH_get)) {
 1242           setobj2s(L, ra, slot);
 1243         }
 1244         else
 1245           Protect(luaV_finishget(L, rb, rc, ra, slot));
 1246         vmbreak;
 1247       }
 1248       vmcase(OP_GETI) {
 1249         const TValue *slot;
 1250         TValue *rb = vRB(i);
 1251         int c = GETARG_C(i);
 1252         if (luaV_fastgeti(L, rb, c, slot)) {
 1253           setobj2s(L, ra, slot);
 1254         }
 1255         else {
 1256           TValue key;
 1257           setivalue(&key, c);
 1258           Protect(luaV_finishget(L, rb, &key, ra, slot));
 1259         }
 1260         vmbreak;
 1261       }
 1262       vmcase(OP_GETFIELD) {
 1263         const TValue *slot;
 1264         TValue *rb = vRB(i);
 1265         TValue *rc = KC(i);
 1266         TString *key = tsvalue(rc);  /* key must be a string */
 1267         if (luaV_fastget(L, rb, key, slot, luaH_getshortstr)) {
 1268           setobj2s(L, ra, slot);
 1269         }
 1270         else
 1271           Protect(luaV_finishget(L, rb, rc, ra, slot));
 1272         vmbreak;
 1273       }
 1274       vmcase(OP_SETTABUP) {
 1275         const TValue *slot;
 1276         TValue *upval = cl->upvals[GETARG_A(i)]->v;
 1277         TValue *rb = KB(i);
 1278         TValue *rc = RKC(i);
 1279         TString *key = tsvalue(rb);  /* key must be a string */
 1280         if (luaV_fastget(L, upval, key, slot, luaH_getshortstr)) {
 1281           luaV_finishfastset(L, upval, slot, rc);
 1282         }
 1283         else
 1284           Protect(luaV_finishset(L, upval, rb, rc, slot));
 1285         vmbreak;
 1286       }
 1287       vmcase(OP_SETTABLE) {
 1288         const TValue *slot;
 1289         TValue *rb = vRB(i);  /* key (table is in 'ra') */
 1290         TValue *rc = RKC(i);  /* value */
 1291         lua_Unsigned n;
 1292         if (ttisinteger(rb)  /* fast track for integers? */
 1293             ? (cast_void(n = ivalue(rb)), luaV_fastgeti(L, s2v(ra), n, slot))
 1294             : luaV_fastget(L, s2v(ra), rb, slot, luaH_get)) {
 1295           luaV_finishfastset(L, s2v(ra), slot, rc);
 1296         }
 1297         else
 1298           Protect(luaV_finishset(L, s2v(ra), rb, rc, slot));
 1299         vmbreak;
 1300       }
 1301       vmcase(OP_SETI) {
 1302         const TValue *slot;
 1303         int c = GETARG_B(i);
 1304         TValue *rc = RKC(i);
 1305         if (luaV_fastgeti(L, s2v(ra), c, slot)) {
 1306           luaV_finishfastset(L, s2v(ra), slot, rc);
 1307         }
 1308         else {
 1309           TValue key;
 1310           setivalue(&key, c);
 1311           Protect(luaV_finishset(L, s2v(ra), &key, rc, slot));
 1312         }
 1313         vmbreak;
 1314       }
 1315       vmcase(OP_SETFIELD) {
 1316         const TValue *slot;
 1317         TValue *rb = KB(i);
 1318         TValue *rc = RKC(i);
 1319         TString *key = tsvalue(rb);  /* key must be a string */
 1320         if (luaV_fastget(L, s2v(ra), key, slot, luaH_getshortstr)) {
 1321           luaV_finishfastset(L, s2v(ra), slot, rc);
 1322         }
 1323         else
 1324           Protect(luaV_finishset(L, s2v(ra), rb, rc, slot));
 1325         vmbreak;
 1326       }
 1327       vmcase(OP_NEWTABLE) {
 1328         int b = GETARG_B(i);  /* log2(hash size) + 1 */
 1329         int c = GETARG_C(i);  /* array size */
 1330         Table *t;
 1331         if (b > 0)
 1332           b = 1 << (b - 1);  /* size is 2^(b - 1) */
 1333         lua_assert((!TESTARG_k(i)) == (GETARG_Ax(*pc) == 0));
 1334         if (TESTARG_k(i))  /* non-zero extra argument? */
 1335           c += GETARG_Ax(*pc) * (MAXARG_C + 1);  /* add it to size */
 1336         pc++;  /* skip extra argument */
 1337         L->top = ra + 1;  /* correct top in case of emergency GC */
 1338         t = luaH_new(L);  /* memory allocation */
 1339         sethvalue2s(L, ra, t);
 1340         if (b != 0 || c != 0)
 1341           luaH_resize(L, t, c, b);  /* idem */
 1342         checkGC(L, ra + 1);
 1343         vmbreak;
 1344       }
 1345       vmcase(OP_SELF) {
 1346         const TValue *slot;
 1347         TValue *rb = vRB(i);
 1348         TValue *rc = RKC(i);
 1349         TString *key = tsvalue(rc);  /* key must be a string */
 1350         setobj2s(L, ra + 1, rb);
 1351         if (luaV_fastget(L, rb, key, slot, luaH_getstr)) {
 1352           setobj2s(L, ra, slot);
 1353         }
 1354         else
 1355           Protect(luaV_finishget(L, rb, rc, ra, slot));
 1356         vmbreak;
 1357       }
 1358       vmcase(OP_ADDI) {
 1359         op_arithI(L, l_addi, luai_numadd);
 1360         vmbreak;
 1361       }
 1362       vmcase(OP_ADDK) {
 1363         op_arithK(L, l_addi, luai_numadd);
 1364         vmbreak;
 1365       }
 1366       vmcase(OP_SUBK) {
 1367         op_arithK(L, l_subi, luai_numsub);
 1368         vmbreak;
 1369       }
 1370       vmcase(OP_MULK) {
 1371         op_arithK(L, l_muli, luai_nummul);
 1372         vmbreak;
 1373       }
 1374       vmcase(OP_MODK) {
 1375         op_arithK(L, luaV_mod, luaV_modf);
 1376         vmbreak;
 1377       }
 1378       vmcase(OP_POWK) {
 1379         op_arithfK(L, luai_numpow);
 1380         vmbreak;
 1381       }
 1382       vmcase(OP_DIVK) {
 1383         op_arithfK(L, luai_numdiv);
 1384         vmbreak;
 1385       }
 1386       vmcase(OP_IDIVK) {
 1387         op_arithK(L, luaV_idiv, luai_numidiv);
 1388         vmbreak;
 1389       }
 1390       vmcase(OP_BANDK) {
 1391         op_bitwiseK(L, l_band);
 1392         vmbreak;
 1393       }
 1394       vmcase(OP_BORK) {
 1395         op_bitwiseK(L, l_bor);
 1396         vmbreak;
 1397       }
 1398       vmcase(OP_BXORK) {
 1399         op_bitwiseK(L, l_bxor);
 1400         vmbreak;
 1401       }
 1402       vmcase(OP_SHRI) {
 1403         TValue *rb = vRB(i);
 1404         int ic = GETARG_sC(i);
 1405         lua_Integer ib;
 1406         if (tointegerns(rb, &ib)) {
 1407           pc++; setivalue(s2v(ra), luaV_shiftl(ib, -ic));
 1408         }
 1409         vmbreak;
 1410       }
 1411       vmcase(OP_SHLI) {
 1412         TValue *rb = vRB(i);
 1413         int ic = GETARG_sC(i);
 1414         lua_Integer ib;
 1415         if (tointegerns(rb, &ib)) {
 1416           pc++; setivalue(s2v(ra), luaV_shiftl(ic, ib));
 1417         }
 1418         vmbreak;
 1419       }
 1420       vmcase(OP_ADD) {
 1421         op_arith(L, l_addi, luai_numadd);
 1422         vmbreak;
 1423       }
 1424       vmcase(OP_SUB) {
 1425         op_arith(L, l_subi, luai_numsub);
 1426         vmbreak;
 1427       }
 1428       vmcase(OP_MUL) {
 1429         op_arith(L, l_muli, luai_nummul);
 1430         vmbreak;
 1431       }
 1432       vmcase(OP_MOD) {
 1433         op_arith(L, luaV_mod, luaV_modf);
 1434         vmbreak;
 1435       }
 1436       vmcase(OP_POW) {
 1437         op_arithf(L, luai_numpow);
 1438         vmbreak;
 1439       }
 1440       vmcase(OP_DIV) {  /* float division (always with floats) */
 1441         op_arithf(L, luai_numdiv);
 1442         vmbreak;
 1443       }
 1444       vmcase(OP_IDIV) {  /* floor division */
 1445         op_arith(L, luaV_idiv, luai_numidiv);
 1446         vmbreak;
 1447       }
 1448       vmcase(OP_BAND) {
 1449         op_bitwise(L, l_band);
 1450         vmbreak;
 1451       }
 1452       vmcase(OP_BOR) {
 1453         op_bitwise(L, l_bor);
 1454         vmbreak;
 1455       }
 1456       vmcase(OP_BXOR) {
 1457         op_bitwise(L, l_bxor);
 1458         vmbreak;
 1459       }
 1460       vmcase(OP_SHR) {
 1461         op_bitwise(L, luaV_shiftr);
 1462         vmbreak;
 1463       }
 1464       vmcase(OP_SHL) {
 1465         op_bitwise(L, luaV_shiftl);
 1466         vmbreak;
 1467       }
 1468       vmcase(OP_MMBIN) {
 1469         Instruction pi = *(pc - 2);  /* original arith. expression */
 1470         TValue *rb = vRB(i);
 1471         TMS tm = (TMS)GETARG_C(i);
 1472         StkId result = RA(pi);
 1473         lua_assert(OP_ADD <= GET_OPCODE(pi) && GET_OPCODE(pi) <= OP_SHR);
 1474         Protect(luaT_trybinTM(L, s2v(ra), rb, result, tm));
 1475         vmbreak;
 1476       }
 1477       vmcase(OP_MMBINI) {
 1478         Instruction pi = *(pc - 2);  /* original arith. expression */
 1479         int imm = GETARG_sB(i);
 1480         TMS tm = (TMS)GETARG_C(i);
 1481         int flip = GETARG_k(i);
 1482         StkId result = RA(pi);
 1483         Protect(luaT_trybiniTM(L, s2v(ra), imm, flip, result, tm));
 1484         vmbreak;
 1485       }
 1486       vmcase(OP_MMBINK) {
 1487         Instruction pi = *(pc - 2);  /* original arith. expression */
 1488         TValue *imm = KB(i);
 1489         TMS tm = (TMS)GETARG_C(i);
 1490         int flip = GETARG_k(i);
 1491         StkId result = RA(pi);
 1492         Protect(luaT_trybinassocTM(L, s2v(ra), imm, flip, result, tm));
 1493         vmbreak;
 1494       }
 1495       vmcase(OP_UNM) {
 1496         TValue *rb = vRB(i);
 1497         lua_Number nb;
 1498         if (ttisinteger(rb)) {
 1499           lua_Integer ib = ivalue(rb);
 1500           setivalue(s2v(ra), intop(-, 0, ib));
 1501         }
 1502         else if (tonumberns(rb, nb)) {
 1503           setfltvalue(s2v(ra), luai_numunm(L, nb));
 1504         }
 1505         else
 1506           Protect(luaT_trybinTM(L, rb, rb, ra, TM_UNM));
 1507         vmbreak;
 1508       }
 1509       vmcase(OP_BNOT) {
 1510         TValue *rb = vRB(i);
 1511         lua_Integer ib;
 1512         if (tointegerns(rb, &ib)) {
 1513           setivalue(s2v(ra), intop(^, ~l_castS2U(0), ib));
 1514         }
 1515         else
 1516           Protect(luaT_trybinTM(L, rb, rb, ra, TM_BNOT));
 1517         vmbreak;
 1518       }
 1519       vmcase(OP_NOT) {
 1520         TValue *rb = vRB(i);
 1521         if (l_isfalse(rb))
 1522           setbtvalue(s2v(ra));
 1523         else
 1524           setbfvalue(s2v(ra));
 1525         vmbreak;
 1526       }
 1527       vmcase(OP_LEN) {
 1528         Protect(luaV_objlen(L, ra, vRB(i)));
 1529         vmbreak;
 1530       }
 1531       vmcase(OP_CONCAT) {
 1532         int n = GETARG_B(i);  /* number of elements to concatenate */
 1533         L->top = ra + n;  /* mark the end of concat operands */
 1534         ProtectNT(luaV_concat(L, n));
 1535         checkGC(L, L->top); /* 'luaV_concat' ensures correct top */
 1536         vmbreak;
 1537       }
 1538       vmcase(OP_CLOSE) {
 1539         Protect(luaF_close(L, ra, LUA_OK, 1));
 1540         vmbreak;
 1541       }
 1542       vmcase(OP_TBC) {
 1543         /* create new to-be-closed upvalue */
 1544         halfProtect(luaF_newtbcupval(L, ra));
 1545         vmbreak;
 1546       }
 1547       vmcase(OP_JMP) {
 1548         dojump(ci, i, 0);
 1549         vmbreak;
 1550       }
 1551       vmcase(OP_EQ) {
 1552         int cond;
 1553         TValue *rb = vRB(i);
 1554         Protect(cond = luaV_equalobj(L, s2v(ra), rb));
 1555         docondjump();
 1556         vmbreak;
 1557       }
 1558       vmcase(OP_LT) {
 1559         op_order(L, l_lti, LTnum, lessthanothers);
 1560         vmbreak;
 1561       }
 1562       vmcase(OP_LE) {
 1563         op_order(L, l_lei, LEnum, lessequalothers);
 1564         vmbreak;
 1565       }
 1566       vmcase(OP_EQK) {
 1567         TValue *rb = KB(i);
 1568         /* basic types do not use '__eq'; we can use raw equality */
 1569         int cond = luaV_rawequalobj(s2v(ra), rb);
 1570         docondjump();
 1571         vmbreak;
 1572       }
 1573       vmcase(OP_EQI) {
 1574         int cond;
 1575         int im = GETARG_sB(i);
 1576         if (ttisinteger(s2v(ra)))
 1577           cond = (ivalue(s2v(ra)) == im);
 1578         else if (ttisfloat(s2v(ra)))
 1579           cond = luai_numeq(fltvalue(s2v(ra)), cast_num(im));
 1580         else
 1581           cond = 0;  /* other types cannot be equal to a number */
 1582         docondjump();
 1583         vmbreak;
 1584       }
 1585       vmcase(OP_LTI) {
 1586         op_orderI(L, l_lti, luai_numlt, 0, TM_LT);
 1587         vmbreak;
 1588       }
 1589       vmcase(OP_LEI) {
 1590         op_orderI(L, l_lei, luai_numle, 0, TM_LE);
 1591         vmbreak;
 1592       }
 1593       vmcase(OP_GTI) {
 1594         op_orderI(L, l_gti, luai_numgt, 1, TM_LT);
 1595         vmbreak;
 1596       }
 1597       vmcase(OP_GEI) {
 1598         op_orderI(L, l_gei, luai_numge, 1, TM_LE);
 1599         vmbreak;
 1600       }
 1601       vmcase(OP_TEST) {
 1602         int cond = !l_isfalse(s2v(ra));
 1603         docondjump();
 1604         vmbreak;
 1605       }
 1606       vmcase(OP_TESTSET) {
 1607         TValue *rb = vRB(i);
 1608         if (l_isfalse(rb) == GETARG_k(i))
 1609           pc++;
 1610         else {
 1611           setobj2s(L, ra, rb);
 1612           donextjump(ci);
 1613         }
 1614         vmbreak;
 1615       }
 1616       vmcase(OP_CALL) {
 1617         CallInfo *newci;
 1618         int b = GETARG_B(i);
 1619         int nresults = GETARG_C(i) - 1;
 1620         if (b != 0)  /* fixed number of arguments? */
 1621           L->top = ra + b;  /* top signals number of arguments */
 1622         /* else previous instruction set top */
 1623         savepc(L);  /* in case of errors */
 1624         if ((newci = luaD_precall(L, ra, nresults)) == NULL)
 1625           updatetrap(ci);  /* C call; nothing else to be done */
 1626         else {  /* Lua call: run function in this same C frame */
 1627           ci = newci;
 1628           ci->callstatus = 0;  /* call re-uses 'luaV_execute' */
 1629           goto startfunc;
 1630         }
 1631         vmbreak;
 1632       }
 1633       vmcase(OP_TAILCALL) {
 1634         int b = GETARG_B(i);  /* number of arguments + 1 (function) */
 1635         int nparams1 = GETARG_C(i);
 1636         /* delta is virtual 'func' - real 'func' (vararg functions) */
 1637         int delta = (nparams1) ? ci->u.l.nextraargs + nparams1 : 0;
 1638         if (b != 0)
 1639           L->top = ra + b;
 1640         else  /* previous instruction set top */
 1641           b = cast_int(L->top - ra);
 1642         savepc(ci);  /* several calls here can raise errors */
 1643         if (TESTARG_k(i)) {
 1644           luaF_closeupval(L, base);  /* close upvalues from current call */
 1645           lua_assert(L->tbclist < base);  /* no pending tbc variables */
 1646           lua_assert(base == ci->func + 1);
 1647         }
 1648         while (!ttisfunction(s2v(ra))) {  /* not a function? */
 1649           luaD_tryfuncTM(L, ra);  /* try '__call' metamethod */
 1650           b++;  /* there is now one extra argument */
 1651           checkstackGCp(L, 1, ra);
 1652         }
 1653         if (!ttisLclosure(s2v(ra))) {  /* C function? */
 1654           luaD_precall(L, ra, LUA_MULTRET);  /* call it */
 1655           updatetrap(ci);
 1656           updatestack(ci);  /* stack may have been relocated */
 1657           ci->func -= delta;  /* restore 'func' (if vararg) */
 1658           luaD_poscall(L, ci, cast_int(L->top - ra));  /* finish caller */
 1659           updatetrap(ci);  /* 'luaD_poscall' can change hooks */
 1660           goto ret;  /* caller returns after the tail call */
 1661         }
 1662         ci->func -= delta;  /* restore 'func' (if vararg) */
 1663         luaD_pretailcall(L, ci, ra, b);  /* prepare call frame */
 1664         goto startfunc;  /* execute the callee */
 1665       }
 1666       vmcase(OP_RETURN) {
 1667         int n = GETARG_B(i) - 1;  /* number of results */
 1668         int nparams1 = GETARG_C(i);
 1669         if (n < 0)  /* not fixed? */
 1670           n = cast_int(L->top - ra);  /* get what is available */
 1671         savepc(ci);
 1672         if (TESTARG_k(i)) {  /* may there be open upvalues? */
 1673           if (L->top < ci->top)
 1674             L->top = ci->top;
 1675           luaF_close(L, base, CLOSEKTOP, 1);
 1676           updatetrap(ci);
 1677           updatestack(ci);
 1678         }
 1679         if (nparams1)  /* vararg function? */
 1680           ci->func -= ci->u.l.nextraargs + nparams1;
 1681         L->top = ra + n;  /* set call for 'luaD_poscall' */
 1682         luaD_poscall(L, ci, n);
 1683         updatetrap(ci);  /* 'luaD_poscall' can change hooks */
 1684         goto ret;
 1685       }
 1686       vmcase(OP_RETURN0) {
 1687         if (l_unlikely(L->hookmask)) {
 1688           L->top = ra;
 1689           savepc(ci);
 1690           luaD_poscall(L, ci, 0);  /* no hurry... */
 1691           trap = 1;
 1692         }
 1693         else {  /* do the 'poscall' here */
 1694           int nres;
 1695           L->ci = ci->previous;  /* back to caller */
 1696           L->top = base - 1;
 1697           for (nres = ci->nresults; l_unlikely(nres > 0); nres--)
 1698             setnilvalue(s2v(L->top++));  /* all results are nil */
 1699         }
 1700         goto ret;
 1701       }
 1702       vmcase(OP_RETURN1) {
 1703         if (l_unlikely(L->hookmask)) {
 1704           L->top = ra + 1;
 1705           savepc(ci);
 1706           luaD_poscall(L, ci, 1);  /* no hurry... */
 1707           trap = 1;
 1708         }
 1709         else {  /* do the 'poscall' here */
 1710           int nres = ci->nresults;
 1711           L->ci = ci->previous;  /* back to caller */
 1712           if (nres == 0)
 1713             L->top = base - 1;  /* asked for no results */
 1714           else {
 1715             setobjs2s(L, base - 1, ra);  /* at least this result */
 1716             L->top = base;
 1717             for (; l_unlikely(nres > 1); nres--)
 1718               setnilvalue(s2v(L->top++));  /* complete missing results */
 1719           }
 1720         }
 1721        ret:  /* return from a Lua function */
 1722         if (ci->callstatus & CIST_FRESH)
 1723           return;  /* end this frame */
 1724         else {
 1725           ci = ci->previous;
 1726           goto returning;  /* continue running caller in this frame */
 1727         }
 1728       }
 1729       vmcase(OP_FORLOOP) {
 1730         if (ttisinteger(s2v(ra + 2))) {  /* integer loop? */
 1731           lua_Unsigned count = l_castS2U(ivalue(s2v(ra + 1)));
 1732           if (count > 0) {  /* still more iterations? */
 1733             lua_Integer step = ivalue(s2v(ra + 2));
 1734             lua_Integer idx = ivalue(s2v(ra));  /* internal index */
 1735             chgivalue(s2v(ra + 1), count - 1);  /* update counter */
 1736             idx = intop(+, idx, step);  /* add step to index */
 1737             chgivalue(s2v(ra), idx);  /* update internal index */
 1738             setivalue(s2v(ra + 3), idx);  /* and control variable */
 1739             pc -= GETARG_Bx(i);  /* jump back */
 1740           }
 1741         }
 1742         else if (floatforloop(ra))  /* float loop */
 1743           pc -= GETARG_Bx(i);  /* jump back */
 1744         updatetrap(ci);  /* allows a signal to break the loop */
 1745         vmbreak;
 1746       }
 1747       vmcase(OP_FORPREP) {
 1748         savestate(L, ci);  /* in case of errors */
 1749         if (forprep(L, ra))
 1750           pc += GETARG_Bx(i) + 1;  /* skip the loop */
 1751         vmbreak;
 1752       }
 1753       vmcase(OP_TFORPREP) {
 1754         /* create to-be-closed upvalue (if needed) */
 1755         halfProtect(luaF_newtbcupval(L, ra + 3));
 1756         pc += GETARG_Bx(i);
 1757         i = *(pc++);  /* go to next instruction */
 1758         lua_assert(GET_OPCODE(i) == OP_TFORCALL && ra == RA(i));
 1759         goto l_tforcall;
 1760       }
 1761       vmcase(OP_TFORCALL) {
 1762        l_tforcall:
 1763         /* 'ra' has the iterator function, 'ra + 1' has the state,
 1764            'ra + 2' has the control variable, and 'ra + 3' has the
 1765            to-be-closed variable. The call will use the stack after
 1766            these values (starting at 'ra + 4')
 1767         */
 1768         /* push function, state, and control variable */
 1769         memcpy(ra + 4, ra, 3 * sizeof(*ra));
 1770         L->top = ra + 4 + 3;
 1771         ProtectNT(luaD_call(L, ra + 4, GETARG_C(i)));  /* do the call */
 1772         updatestack(ci);  /* stack may have changed */
 1773         i = *(pc++);  /* go to next instruction */
 1774         lua_assert(GET_OPCODE(i) == OP_TFORLOOP && ra == RA(i));
 1775         goto l_tforloop;
 1776       }
 1777       vmcase(OP_TFORLOOP) {
 1778         l_tforloop:
 1779         if (!ttisnil(s2v(ra + 4))) {  /* continue loop? */
 1780           setobjs2s(L, ra + 2, ra + 4);  /* save control variable */
 1781           pc -= GETARG_Bx(i);  /* jump back */
 1782         }
 1783         vmbreak;
 1784       }
 1785       vmcase(OP_SETLIST) {
 1786         int n = GETARG_B(i);
 1787         unsigned int last = GETARG_C(i);
 1788         Table *h = hvalue(s2v(ra));
 1789         if (n == 0)
 1790           n = cast_int(L->top - ra) - 1;  /* get up to the top */
 1791         else
 1792           L->top = ci->top;  /* correct top in case of emergency GC */
 1793         last += n;
 1794         if (TESTARG_k(i)) {
 1795           last += GETARG_Ax(*pc) * (MAXARG_C + 1);
 1796           pc++;
 1797         }
 1798         if (last > luaH_realasize(h))  /* needs more space? */
 1799           luaH_resizearray(L, h, last);  /* preallocate it at once */
 1800         for (; n > 0; n--) {
 1801           TValue *val = s2v(ra + n);
 1802           setobj2t(L, &h->array[last - 1], val);
 1803           last--;
 1804           luaC_barrierback(L, obj2gco(h), val);
 1805         }
 1806         vmbreak;
 1807       }
 1808       vmcase(OP_CLOSURE) {
 1809         Proto *p = cl->p->p[GETARG_Bx(i)];
 1810         halfProtect(pushclosure(L, p, cl->upvals, base, ra));
 1811         checkGC(L, ra + 1);
 1812         vmbreak;
 1813       }
 1814       vmcase(OP_VARARG) {
 1815         int n = GETARG_C(i) - 1;  /* required results */
 1816         Protect(luaT_getvarargs(L, ci, ra, n));
 1817         vmbreak;
 1818       }
 1819       vmcase(OP_VARARGPREP) {
 1820         ProtectNT(luaT_adjustvarargs(L, GETARG_A(i), ci, cl->p));
 1821         if (l_unlikely(trap)) {  /* previous "Protect" updated trap */
 1822           luaD_hookcall(L, ci);
 1823           L->oldpc = 1;  /* next opcode will be seen as a "new" line */
 1824         }
 1825         updatebase(ci);  /* function has new base after adjustment */
 1826         vmbreak;
 1827       }
 1828       vmcase(OP_EXTRAARG) {
 1829         lua_assert(0);
 1830         vmbreak;
 1831       }
 1832     }
 1833   }
 1834 }
 1835 
 1836 /* }================================================================== */