LICENSE


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MIT/X Consortium License

(C)opyright MMVI-MMVII Anselm R. Garbe <garbeam at gmail dot com>
(C)opyright MMVI-MMVII Sander van Dijk <a dot h dot vandijk at gmail dot com>

Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and associated documentation files (the "Software"),
to deal in the Software without restriction, including without limitation
the rights to use, copy, modify, merge, publish, distribute, sublicense,
and/or sell copies of the Software, and to permit persons to whom the 
Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in 
all copies or substantial portions of the Software. 

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL 
THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
DEALINGS IN THE SOFTWARE.
/*
** $Id: lvm.c,v 2.63.1.5 2011/08/17 20:43:11 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;
  TValue temp;
  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);
        h->flags = 0;
        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;
    }
    /* else repeat with `tm' */
    setobj(L, &temp, tm);  /* avoid pointing inside table (may rehash) */
    t = &temp;
  }
  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;
      }
    }
  }
}