/*

 ** $Id: lvm.c,v 2.63.1.3 2007/12/28 15:32:23 roberto Exp $

 ** Lua virtual machine

 ** See Copyright Notice in lua.h

 */

 

 

 #include <stdio.h>

 #include <stdlib.h>

 #include <string.h>

 

 #define lvm_c

 #define LUA_CORE

 

 #include "lua.h"

 

 #include "ldebug.h"

 #include "ldo.h"

 #include "lfunc.h"

 #include "lgc.h"

 #include "lobject.h"

 #include "lopcodes.h"

 #include "lstate.h"

 #include "lstring.h"

 #include "ltable.h"

 #include "ltm.h"

 #include "lvm.h"

 

 

 

 /* limit for table tag-method chains (to avoid loops) */

 #define MAXTAGLOOP	100

 

 

 const TValue *luaV_tonumber (const TValue *obj, TValue *n) {

   lua_Number num;

   if (ttisnumber(obj)) return obj;

   if (ttisstring(obj) && luaO_str2d(svalue(obj), &num)) {

     setnvalue(n, num);

     return n;

   }

   else

     return NULL;

 }

 

 

 int luaV_tostring (lua_State *L, StkId obj) {

   if (!ttisnumber(obj))

     return 0;

   else {

     char s[LUAI_MAXNUMBER2STR];

     lua_Number n = nvalue(obj);

     lua_number2str(s, n);

     setsvalue2s(L, obj, luaS_new(L, s));

     return 1;

   }

 }

 

 

 static void traceexec (lua_State *L, const Instruction *pc) {

   lu_byte mask = L->hookmask;

   const Instruction *oldpc = L->savedpc;

   L->savedpc = pc;

   if ((mask & LUA_MASKCOUNT) && L->hookcount == 0) {

     resethookcount(L);

     luaD_callhook(L, LUA_HOOKCOUNT, -1);

   }

   if (mask & LUA_MASKLINE) {

     Proto *p = ci_func(L->ci)->l.p;

     int npc = pcRel(pc, p);

     int newline = getline(p, npc);

     /* call linehook when enter a new function, when jump back (loop),

        or when enter a new line */

     if (npc == 0 || pc <= oldpc || newline != getline(p, pcRel(oldpc, p)))

       luaD_callhook(L, LUA_HOOKLINE, newline);

   }

 }

 

 

 static void callTMres (lua_State *L, StkId res, const TValue *f,

                         const TValue *p1, const TValue *p2) {

   ptrdiff_t result = savestack(L, res);

   setobj2s(L, L->top, f);  /* push function */

   setobj2s(L, L->top+1, p1);  /* 1st argument */

   setobj2s(L, L->top+2, p2);  /* 2nd argument */

   luaD_checkstack(L, 3);

   L->top += 3;

   luaD_call(L, L->top - 3, 1);

   res = restorestack(L, result);

   L->top--;

   setobjs2s(L, res, L->top);

 }

 

 

 

 static void callTM (lua_State *L, const TValue *f, const TValue *p1,

                     const TValue *p2, const TValue *p3) {

   setobj2s(L, L->top, f);  /* push function */

   setobj2s(L, L->top+1, p1);  /* 1st argument */

   setobj2s(L, L->top+2, p2);  /* 2nd argument */

   setobj2s(L, L->top+3, p3);  /* 3th argument */

   luaD_checkstack(L, 4);

   L->top += 4;

   luaD_call(L, L->top - 4, 0);

 }

 

 

 void luaV_gettable (lua_State *L, const TValue *t, TValue *key, StkId val) {

   int loop;

   for (loop = 0; loop < MAXTAGLOOP; loop++) {

     const TValue *tm;

     if (ttistable(t)) {  /* `t' is a table? */

       Table *h = hvalue(t);

       const TValue *res = luaH_get(h, key); /* do a primitive get */

       if (!ttisnil(res) ||  /* result is no nil? */

           (tm = fasttm(L, h->metatable, TM_INDEX)) == NULL) { /* or no TM? */

         setobj2s(L, val, res);

         return;

       }

       /* else will try the tag method */

     }

     else if (ttisnil(tm = luaT_gettmbyobj(L, t, TM_INDEX)))

       luaG_typeerror(L, t, "index");

     if (ttisfunction(tm)) {

       callTMres(L, val, tm, t, key);

       return;

     }

     t = tm;  /* else repeat with `tm' */ 

   }

   luaG_runerror(L, "loop in gettable");

 }

 

 

 void luaV_settable (lua_State *L, const TValue *t, TValue *key, StkId val) {

   int loop;

   for (loop = 0; loop < MAXTAGLOOP; loop++) {

     const TValue *tm;

     if (ttistable(t)) {  /* `t' is a table? */

       Table *h = hvalue(t);

       TValue *oldval = luaH_set(L, h, key); /* do a primitive set */

       if (!ttisnil(oldval) ||  /* result is no nil? */

           (tm = fasttm(L, h->metatable, TM_NEWINDEX)) == NULL) { /* or no TM? */

         setobj2t(L, oldval, val);

         luaC_barriert(L, h, val);

         return;

       }

       /* else will try the tag method */

     }

     else if (ttisnil(tm = luaT_gettmbyobj(L, t, TM_NEWINDEX)))

       luaG_typeerror(L, t, "index");

     if (ttisfunction(tm)) {

       callTM(L, tm, t, key, val);

       return;

     }

     t = tm;  /* else repeat with `tm' */ 

   }

   luaG_runerror(L, "loop in settable");

 }

 

 

 static int call_binTM (lua_State *L, const TValue *p1, const TValue *p2,

                        StkId res, TMS event) {

   const TValue *tm = luaT_gettmbyobj(L, p1, event);  /* try first operand */

   if (ttisnil(tm))

     tm = luaT_gettmbyobj(L, p2, event);  /* try second operand */

   if (ttisnil(tm)) return 0;

   callTMres(L, res, tm, p1, p2);

   return 1;

 }

 

 

 static const TValue *get_compTM (lua_State *L, Table *mt1, Table *mt2,

                                   TMS event) {

   const TValue *tm1 = fasttm(L, mt1, event);

   const TValue *tm2;

   if (tm1 == NULL) return NULL;  /* no metamethod */

   if (mt1 == mt2) return tm1;  /* same metatables => same metamethods */

   tm2 = fasttm(L, mt2, event);

   if (tm2 == NULL) return NULL;  /* no metamethod */

   if (luaO_rawequalObj(tm1, tm2))  /* same metamethods? */

     return tm1;

   return NULL;

 }

 

 

 static int call_orderTM (lua_State *L, const TValue *p1, const TValue *p2,

                          TMS event) {

   const TValue *tm1 = luaT_gettmbyobj(L, p1, event);

   const TValue *tm2;

   if (ttisnil(tm1)) return -1;  /* no metamethod? */

   tm2 = luaT_gettmbyobj(L, p2, event);

   if (!luaO_rawequalObj(tm1, tm2))  /* different metamethods? */

     return -1;

   callTMres(L, L->top, tm1, p1, p2);

   return !l_isfalse(L->top);

 }

 

 

 static int l_strcmp (const TString *ls, const TString *rs) {

   const char *l = getstr(ls);

   size_t ll = ls->tsv.len;

   const char *r = getstr(rs);

   size_t lr = rs->tsv.len;

   for (;;) {

     int temp = strcoll(l, r);

     if (temp != 0) return temp;

     else {  /* strings are equal up to a `\0' */

       size_t len = strlen(l);  /* index of first `\0' in both strings */

       if (len == lr)  /* r is finished? */

         return (len == ll) ? 0 : 1;

       else if (len == ll)  /* l is finished? */

         return -1;  /* l is smaller than r (because r is not finished) */

       /* both strings longer than `len'; go on comparing (after the `\0') */

       len++;

       l += len; ll -= len; r += len; lr -= len;

     }

   }

 }

 

 

 int luaV_lessthan (lua_State *L, const TValue *l, const TValue *r) {

   int res;

   if (ttype(l) != ttype(r))

     return luaG_ordererror(L, l, r);

   else if (ttisnumber(l))

     return luai_numlt(nvalue(l), nvalue(r));

   else if (ttisstring(l))

     return l_strcmp(rawtsvalue(l), rawtsvalue(r)) < 0;

   else if ((res = call_orderTM(L, l, r, TM_LT)) != -1)

     return res;

   return luaG_ordererror(L, l, r);

 }

 

 

 static int lessequal (lua_State *L, const TValue *l, const TValue *r) {

   int res;

   if (ttype(l) != ttype(r))

     return luaG_ordererror(L, l, r);

   else if (ttisnumber(l))

     return luai_numle(nvalue(l), nvalue(r));

   else if (ttisstring(l))

     return l_strcmp(rawtsvalue(l), rawtsvalue(r)) <= 0;

   else if ((res = call_orderTM(L, l, r, TM_LE)) != -1)  /* first try `le' */

     return res;

   else if ((res = call_orderTM(L, r, l, TM_LT)) != -1)  /* else try `lt' */

     return !res;

   return luaG_ordererror(L, l, r);

 }

 

 

 int luaV_equalval (lua_State *L, const TValue *t1, const TValue *t2) {

   const TValue *tm;

   lua_assert(ttype(t1) == ttype(t2));

   switch (ttype(t1)) {

     case LUA_TNIL: return 1;

     case LUA_TNUMBER: return luai_numeq(nvalue(t1), nvalue(t2));

     case LUA_TBOOLEAN: return bvalue(t1) == bvalue(t2);  /* true must be 1 !! */

     case LUA_TLIGHTUSERDATA: return pvalue(t1) == pvalue(t2);

     case LUA_TUSERDATA: {

       if (uvalue(t1) == uvalue(t2)) return 1;

       tm = get_compTM(L, uvalue(t1)->metatable, uvalue(t2)->metatable,

                          TM_EQ);

       break;  /* will try TM */

     }

     case LUA_TTABLE: {

       if (hvalue(t1) == hvalue(t2)) return 1;

       tm = get_compTM(L, hvalue(t1)->metatable, hvalue(t2)->metatable, TM_EQ);

       break;  /* will try TM */

     }

     default: return gcvalue(t1) == gcvalue(t2);

   }

   if (tm == NULL) return 0;  /* no TM? */

   callTMres(L, L->top, tm, t1, t2);  /* call TM */

   return !l_isfalse(L->top);

 }

 

 

 void luaV_concat (lua_State *L, int total, int last) {

   do {

     StkId top = L->base + last + 1;

     int n = 2;  /* number of elements handled in this pass (at least 2) */

     if (!(ttisstring(top-2) || ttisnumber(top-2)) || !tostring(L, top-1)) {

       if (!call_binTM(L, top-2, top-1, top-2, TM_CONCAT))

         luaG_concaterror(L, top-2, top-1);

     } else if (tsvalue(top-1)->len == 0)  /* second op is empty? */

       (void)tostring(L, top - 2);  /* result is first op (as string) */

     else {

       /* at least two string values; get as many as possible */

       size_t tl = tsvalue(top-1)->len;

       char *buffer;

       int i;

       /* collect total length */

       for (n = 1; n < total && tostring(L, top-n-1); n++) {

         size_t l = tsvalue(top-n-1)->len;

         if (l >= MAX_SIZET - tl) luaG_runerror(L, "string length overflow");

         tl += l;

       }

       buffer = luaZ_openspace(L, &G(L)->buff, tl);

       tl = 0;

       for (i=n; i>0; i--) {  /* concat all strings */

         size_t l = tsvalue(top-i)->len;

         memcpy(buffer+tl, svalue(top-i), l);

         tl += l;

       }

       setsvalue2s(L, top-n, luaS_newlstr(L, buffer, tl));

     }

     total -= n-1;  /* got `n' strings to create 1 new */

     last -= n-1;

   } while (total > 1);  /* repeat until only 1 result left */

 }

 

 

 static void Arith (lua_State *L, StkId ra, const TValue *rb,

                    const TValue *rc, TMS op) {

   TValue tempb, tempc;

   const TValue *b, *c;

   if ((b = luaV_tonumber(rb, &tempb)) != NULL &&

       (c = luaV_tonumber(rc, &tempc)) != NULL) {

     lua_Number nb = nvalue(b), nc = nvalue(c);

     switch (op) {

       case TM_ADD: setnvalue(ra, luai_numadd(nb, nc)); break;

       case TM_SUB: setnvalue(ra, luai_numsub(nb, nc)); break;

       case TM_MUL: setnvalue(ra, luai_nummul(nb, nc)); break;

       case TM_DIV: setnvalue(ra, luai_numdiv(nb, nc)); break;

       case TM_MOD: setnvalue(ra, luai_nummod(nb, nc)); break;

       case TM_POW: setnvalue(ra, luai_numpow(nb, nc)); break;

       case TM_UNM: setnvalue(ra, luai_numunm(nb)); break;

       default: lua_assert(0); break;

     }

   }

   else if (!call_binTM(L, rb, rc, ra, op))

     luaG_aritherror(L, rb, rc);

 }

 

 

 

 /*

 ** some macros for common tasks in `luaV_execute'

 */

 

 #define runtime_check(L, c)	{ if (!(c)) break; }

 

 #define RA(i)	(base+GETARG_A(i))

 /* to be used after possible stack reallocation */

 #define RB(i)	check_exp(getBMode(GET_OPCODE(i)) == OpArgR, base+GETARG_B(i))

 #define RC(i)	check_exp(getCMode(GET_OPCODE(i)) == OpArgR, base+GETARG_C(i))

 #define RKB(i)	check_exp(getBMode(GET_OPCODE(i)) == OpArgK, \

 	ISK(GETARG_B(i)) ? k+INDEXK(GETARG_B(i)) : base+GETARG_B(i))

 #define RKC(i)	check_exp(getCMode(GET_OPCODE(i)) == OpArgK, \

 	ISK(GETARG_C(i)) ? k+INDEXK(GETARG_C(i)) : base+GETARG_C(i))

 #define KBx(i)	check_exp(getBMode(GET_OPCODE(i)) == OpArgK, k+GETARG_Bx(i))

 

 

 #define dojump(L,pc,i)	{(pc) += (i); luai_threadyield(L);}

 

 

 #define Protect(x)	{ L->savedpc = pc; {x;}; base = L->base; }

 

 

 #define arith_op(op,tm) { \

         TValue *rb = RKB(i); \

         TValue *rc = RKC(i); \

         if (ttisnumber(rb) && ttisnumber(rc)) { \

           lua_Number nb = nvalue(rb), nc = nvalue(rc); \

           setnvalue(ra, op(nb, nc)); \

         } \

         else \

           Protect(Arith(L, ra, rb, rc, tm)); \

       }

 

 

 

 void luaV_execute (lua_State *L, int nexeccalls) {

   LClosure *cl;

   StkId base;

   TValue *k;

   const Instruction *pc;

  reentry:  /* entry point */

   lua_assert(isLua(L->ci));

   pc = L->savedpc;

   cl = &clvalue(L->ci->func)->l;

   base = L->base;

   k = cl->p->k;

   /* main loop of interpreter */

   for (;;) {

     const Instruction i = *pc++;

     StkId ra;

     if ((L->hookmask & (LUA_MASKLINE | LUA_MASKCOUNT)) &&

         (--L->hookcount == 0 || L->hookmask & LUA_MASKLINE)) {

       traceexec(L, pc);

       if (L->status == LUA_YIELD) {  /* did hook yield? */

         L->savedpc = pc - 1;

         return;

       }

       base = L->base;

     }

     /* warning!! several calls may realloc the stack and invalidate `ra' */

     ra = RA(i);

     lua_assert(base == L->base && L->base == L->ci->base);

     lua_assert(base <= L->top && L->top <= L->stack + L->stacksize);

     lua_assert(L->top == L->ci->top || luaG_checkopenop(i));

     switch (GET_OPCODE(i)) {

       case OP_MOVE: {

         setobjs2s(L, ra, RB(i));

         continue;

       }

       case OP_LOADK: {

         setobj2s(L, ra, KBx(i));

         continue;

       }

       case OP_LOADBOOL: {

         setbvalue(ra, GETARG_B(i));

         if (GETARG_C(i)) pc++;  /* skip next instruction (if C) */

         continue;

       }

       case OP_LOADNIL: {

         TValue *rb = RB(i);

         do {

           setnilvalue(rb--);

         } while (rb >= ra);

         continue;

       }

       case OP_GETUPVAL: {

         int b = GETARG_B(i);

         setobj2s(L, ra, cl->upvals[b]->v);

         continue;

       }

       case OP_GETGLOBAL: {

         TValue g;

         TValue *rb = KBx(i);

         sethvalue(L, &g, cl->env);

         lua_assert(ttisstring(rb));

         Protect(luaV_gettable(L, &g, rb, ra));

         continue;

       }

       case OP_GETTABLE: {

         Protect(luaV_gettable(L, RB(i), RKC(i), ra));

         continue;

       }

       case OP_SETGLOBAL: {

         TValue g;

         sethvalue(L, &g, cl->env);

         lua_assert(ttisstring(KBx(i)));

         Protect(luaV_settable(L, &g, KBx(i), ra));

         continue;

       }

       case OP_SETUPVAL: {

         UpVal *uv = cl->upvals[GETARG_B(i)];

         setobj(L, uv->v, ra);

         luaC_barrier(L, uv, ra);

         continue;

       }

       case OP_SETTABLE: {

         Protect(luaV_settable(L, ra, RKB(i), RKC(i)));

         continue;

       }

       case OP_NEWTABLE: {

         int b = GETARG_B(i);

         int c = GETARG_C(i);

         sethvalue(L, ra, luaH_new(L, luaO_fb2int(b), luaO_fb2int(c)));

         Protect(luaC_checkGC(L));

         continue;

       }

       case OP_SELF: {

         StkId rb = RB(i);

         setobjs2s(L, ra+1, rb);

         Protect(luaV_gettable(L, rb, RKC(i), ra));

         continue;

       }

       case OP_ADD: {

         arith_op(luai_numadd, TM_ADD);

         continue;

       }

       case OP_SUB: {

         arith_op(luai_numsub, TM_SUB);

         continue;

       }

       case OP_MUL: {

         arith_op(luai_nummul, TM_MUL);

         continue;

       }

       case OP_DIV: {

         arith_op(luai_numdiv, TM_DIV);

         continue;

       }

       case OP_MOD: {

         arith_op(luai_nummod, TM_MOD);

         continue;

       }

       case OP_POW: {

         arith_op(luai_numpow, TM_POW);

         continue;

       }

       case OP_UNM: {

         TValue *rb = RB(i);

         if (ttisnumber(rb)) {

           lua_Number nb = nvalue(rb);

           setnvalue(ra, luai_numunm(nb));

         }

         else {

           Protect(Arith(L, ra, rb, rb, TM_UNM));

         }

         continue;

       }

       case OP_NOT: {

         int res = l_isfalse(RB(i));  /* next assignment may change this value */

         setbvalue(ra, res);

         continue;

       }

       case OP_LEN: {

         const TValue *rb = RB(i);

         switch (ttype(rb)) {

           case LUA_TTABLE: {

             setnvalue(ra, cast_num(luaH_getn(hvalue(rb))));

             break;

           }

           case LUA_TSTRING: {

             setnvalue(ra, cast_num(tsvalue(rb)->len));

             break;

           }

           default: {  /* try metamethod */

             Protect(

               if (!call_binTM(L, rb, luaO_nilobject, ra, TM_LEN))

                 luaG_typeerror(L, rb, "get length of");

             )

           }

         }

         continue;

       }

       case OP_CONCAT: {

         int b = GETARG_B(i);

         int c = GETARG_C(i);

         Protect(luaV_concat(L, c-b+1, c); luaC_checkGC(L));

         setobjs2s(L, RA(i), base+b);

         continue;

       }

       case OP_JMP: {

         dojump(L, pc, GETARG_sBx(i));

         continue;

       }

       case OP_EQ: {

         TValue *rb = RKB(i);

         TValue *rc = RKC(i);

         Protect(

           if (equalobj(L, rb, rc) == GETARG_A(i))

             dojump(L, pc, GETARG_sBx(*pc));

         )

         pc++;

         continue;

       }

       case OP_LT: {

         Protect(

           if (luaV_lessthan(L, RKB(i), RKC(i)) == GETARG_A(i))

             dojump(L, pc, GETARG_sBx(*pc));

         )

         pc++;

         continue;

       }

       case OP_LE: {

         Protect(

           if (lessequal(L, RKB(i), RKC(i)) == GETARG_A(i))

             dojump(L, pc, GETARG_sBx(*pc));

         )

         pc++;

         continue;

       }

       case OP_TEST: {

         if (l_isfalse(ra) != GETARG_C(i))

           dojump(L, pc, GETARG_sBx(*pc));

         pc++;

         continue;

       }

       case OP_TESTSET: {

         TValue *rb = RB(i);

         if (l_isfalse(rb) != GETARG_C(i)) {

           setobjs2s(L, ra, rb);

           dojump(L, pc, GETARG_sBx(*pc));

         }

         pc++;

         continue;

       }

       case OP_CALL: {

         int b = GETARG_B(i);

         int nresults = GETARG_C(i) - 1;

         if (b != 0) L->top = ra+b;  /* else previous instruction set top */

         L->savedpc = pc;

         switch (luaD_precall(L, ra, nresults)) {

           case PCRLUA: {

             nexeccalls++;

             goto reentry;  /* restart luaV_execute over new Lua function */

           }

           case PCRC: {

             /* it was a C function (`precall' called it); adjust results */

             if (nresults >= 0) L->top = L->ci->top;

             base = L->base;

             continue;

           }

           default: {

             return;  /* yield */

           }

         }

       }

       case OP_TAILCALL: {

         int b = GETARG_B(i);

         if (b != 0) L->top = ra+b;  /* else previous instruction set top */

         L->savedpc = pc;

         lua_assert(GETARG_C(i) - 1 == LUA_MULTRET);

         switch (luaD_precall(L, ra, LUA_MULTRET)) {

           case PCRLUA: {

             /* tail call: put new frame in place of previous one */

             CallInfo *ci = L->ci - 1;  /* previous frame */

             int aux;

             StkId func = ci->func;

             StkId pfunc = (ci+1)->func;  /* previous function index */

             if (L->openupval) luaF_close(L, ci->base);

             L->base = ci->base = ci->func + ((ci+1)->base - pfunc);

             for (aux = 0; pfunc+aux < L->top; aux++)  /* move frame down */

               setobjs2s(L, func+aux, pfunc+aux);

             ci->top = L->top = func+aux;  /* correct top */

             lua_assert(L->top == L->base + clvalue(func)->l.p->maxstacksize);

             ci->savedpc = L->savedpc;

             ci->tailcalls++;  /* one more call lost */

             L->ci--;  /* remove new frame */

             goto reentry;

           }

           case PCRC: {  /* it was a C function (`precall' called it) */

             base = L->base;

             continue;

           }

           default: {

             return;  /* yield */

           }

         }

       }

       case OP_RETURN: {

         int b = GETARG_B(i);

         if (b != 0) L->top = ra+b-1;

         if (L->openupval) luaF_close(L, base);

         L->savedpc = pc;

         b = luaD_poscall(L, ra);

         if (--nexeccalls == 0)  /* was previous function running `here'? */

           return;  /* no: return */

         else {  /* yes: continue its execution */

           if (b) L->top = L->ci->top;

           lua_assert(isLua(L->ci));

           lua_assert(GET_OPCODE(*((L->ci)->savedpc - 1)) == OP_CALL);

           goto reentry;

         }

       }

       case OP_FORLOOP: {

         lua_Number step = nvalue(ra+2);

         lua_Number idx = luai_numadd(nvalue(ra), step); /* increment index */

         lua_Number limit = nvalue(ra+1);

         if (luai_numlt(0, step) ? luai_numle(idx, limit)

                                 : luai_numle(limit, idx)) {

           dojump(L, pc, GETARG_sBx(i));  /* jump back */

           setnvalue(ra, idx);  /* update internal index... */

           setnvalue(ra+3, idx);  /* ...and external index */

         }

         continue;

       }

       case OP_FORPREP: {

         const TValue *init = ra;

         const TValue *plimit = ra+1;

         const TValue *pstep = ra+2;

         L->savedpc = pc;  /* next steps may throw errors */

         if (!tonumber(init, ra))

           luaG_runerror(L, LUA_QL("for") " initial value must be a number");

         else if (!tonumber(plimit, ra+1))

           luaG_runerror(L, LUA_QL("for") " limit must be a number");

         else if (!tonumber(pstep, ra+2))

           luaG_runerror(L, LUA_QL("for") " step must be a number");

         setnvalue(ra, luai_numsub(nvalue(ra), nvalue(pstep)));

         dojump(L, pc, GETARG_sBx(i));

         continue;

       }

       case OP_TFORLOOP: {

         StkId cb = ra + 3;  /* call base */

         setobjs2s(L, cb+2, ra+2);

         setobjs2s(L, cb+1, ra+1);

         setobjs2s(L, cb, ra);

         L->top = cb+3;  /* func. + 2 args (state and index) */

         Protect(luaD_call(L, cb, GETARG_C(i)));

         L->top = L->ci->top;

         cb = RA(i) + 3;  /* previous call may change the stack */

         if (!ttisnil(cb)) {  /* continue loop? */

           setobjs2s(L, cb-1, cb);  /* save control variable */

           dojump(L, pc, GETARG_sBx(*pc));  /* jump back */

         }

         pc++;

         continue;

       }

       case OP_SETLIST: {

         int n = GETARG_B(i);

         int c = GETARG_C(i);

         int last;

         Table *h;

         if (n == 0) {

           n = cast_int(L->top - ra) - 1;

           L->top = L->ci->top;

         }

         if (c == 0) c = cast_int(*pc++);

         runtime_check(L, ttistable(ra));

         h = hvalue(ra);

         last = ((c-1)*LFIELDS_PER_FLUSH) + n;

         if (last > h->sizearray)  /* needs more space? */

           luaH_resizearray(L, h, last);  /* pre-alloc it at once */

         for (; n > 0; n--) {

           TValue *val = ra+n;

           setobj2t(L, luaH_setnum(L, h, last--), val);

           luaC_barriert(L, h, val);

         }

         continue;

       }

       case OP_CLOSE: {

         luaF_close(L, ra);

         continue;

       }

       case OP_CLOSURE: {

         Proto *p;

         Closure *ncl;

         int nup, j;

         p = cl->p->p[GETARG_Bx(i)];

         nup = p->nups;

         ncl = luaF_newLclosure(L, nup, cl->env);

         ncl->l.p = p;

         for (j=0; j<nup; j++, pc++) {

           if (GET_OPCODE(*pc) == OP_GETUPVAL)

             ncl->l.upvals[j] = cl->upvals[GETARG_B(*pc)];

           else {

             lua_assert(GET_OPCODE(*pc) == OP_MOVE);

             ncl->l.upvals[j] = luaF_findupval(L, base + GETARG_B(*pc));

           }

         }

         setclvalue(L, ra, ncl);

         Protect(luaC_checkGC(L));

         continue;

       }

       case OP_VARARG: {

         int b = GETARG_B(i) - 1;

         int j;

         CallInfo *ci = L->ci;

         int n = cast_int(ci->base - ci->func) - cl->p->numparams - 1;

         if (b == LUA_MULTRET) {

           Protect(luaD_checkstack(L, n));

           ra = RA(i);  /* previous call may change the stack */

           b = n;

           L->top = ra + n;

         }

         for (j = 0; j < b; j++) {

           if (j < n) {

             setobjs2s(L, ra + j, ci->base - n + j);

           }

           else {

             setnilvalue(ra + j);

           }

         }

         continue;

       }

     }

   }

 }