text: /*
  ** $Id: lvm.c,v 2.63.1.4 2009/07/01 21:10:33 roberto Exp $
  ** Lua virtual machine
  ** See Copyright Notice in lua.h
  */
  
  
  #include "c_stdio.h"
  #include "c_stdlib.h"
  #include "c_string.h"
  #include "c_math.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"
  #include "lrotable.h"
  
  
  /* limit for table tag-method chains (to avoid loops) */
  #define MAXTAGLOOP	100
  
  #if defined LUA_NUMBER_INTEGRAL
  LUA_NUMBER luai_ipow(LUA_NUMBER a, LUA_NUMBER b) {
    if (b < 0)
      return 0;
    else if (b == 0)
      return 1;
    else {
      LUA_NUMBER c = 1;
      for (;;) {
        if (b & 1)
  	c *= a;
        b = b >> 1;
        if (b == 0)
  	return c;
        a *= a;
      }
    }
  }
  #endif
  
  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];
      ptrdiff_t objr = savestack(L, obj);
      lua_Number n = nvalue(obj);
      lua_number2str(s, n);
      setsvalue2s(L, restorestack(L, objr), 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;
    TValue temp;
    for (loop = 0; loop < MAXTAGLOOP; loop++) {
      const TValue *tm;
      if (ttistable(t) || ttisrotable(t)) {  /* `t' is a table? */
        void *h = ttistable(t) ? hvalue(t) : rvalue(t);
        const TValue *res = ttistable(t) ? luaH_get((Table*)h, key) : luaH_get_ro(h, key); /* do a primitive get */
        if (!ttisnil(res) ||  /* result is no nil? */
            (tm = fasttm(L, ttistable(t) ? ((Table*)h)->metatable : (Table*)luaR_getmeta(h), 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) || ttislightfunction(tm)) {
        callTMres(L, val, tm, t, key);
        return;
      }
      /* else repeat with `tm' */
      setobj(L, &temp, tm);  /* avoid pointing inside table (may rehash) */
      t = &temp;
    }
    luaG_runerror(L, "loop in gettable");
  }
  
  
  void luaV_settable (lua_State *L, const TValue *t, TValue *key, StkId val) {
    int loop;
    TValue temp;
    setnilvalue(L->top);
    L->top++;
    fixedstack(L);
    for (loop = 0; loop < MAXTAGLOOP; loop++) {
      const TValue *tm;
      if (ttistable(t) || ttisrotable(t)) {  /* `t' is a table? */
        void *h = ttistable(t) ? hvalue(t) : rvalue(t);
        TValue *oldval = ttistable(t) ? luaH_set(L, (Table*)h, key) : NULL; /* do a primitive set */
        if ((oldval && !ttisnil(oldval)) ||  /* result is no nil? */
            (tm = fasttm(L, ttistable(t) ? ((Table*)h)->metatable : (Table*)luaR_getmeta(h), TM_NEWINDEX)) == NULL) { /* or no TM? */
          if(oldval) {
            L->top--;
            unfixedstack(L);
            setobj2t(L, oldval, val);
            ((Table *)h)->flags = 0;
            luaC_barriert(L, (Table*)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) || ttislightfunction(tm)) {
        L->top--;
        unfixedstack(L);
        callTM(L, tm, t, key, val);
        return;
      }
      /* else repeat with `tm' */
      setobj(L, &temp, tm);  /* avoid pointing inside table (may rehash) */
      t = &temp;
      setobj2s(L, L->top-1, t);  /* need to protect value from EGC. */
    }
    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 = c_strcoll(l, r);
      if (temp != 0) return temp;
      else {  /* strings are equal up to a `\0' */
        size_t len = c_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: 
      case LUA_TROTABLE:
      case LUA_TLIGHTFUNCTION:
        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) {
    lu_mem max_sizet = MAX_SIZET;
    if (G(L)->memlimit < max_sizet) max_sizet = G(L)->memlimit;
    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)) {
          /* restore 'top' pointer, since stack might have been reallocted */
          top = L->base + last + 1;
          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;
        fixedstack(L);
        /* 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;
        }
        G(L)->buff.n = tl;
        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;
          c_memcpy(buffer+tl, svalue(top-i), l);
          tl += l;
        }
        setsvalue2s(L, top-n, luaS_newlstr(L, buffer, tl));
        luaZ_resetbuffer(&G(L)->buff);
        unfixedstack(L);
      }
      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_lnumdiv(nb, nc)); break;
        case TM_MOD: setnvalue(ra, luai_lnummod(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 {
      ptrdiff_t br = savestack(L, rb);
      ptrdiff_t cr = savestack(L, rc);
      if (!call_binTM(L, rb, rc, ra, op)) {
        luaG_aritherror(L, restorestack(L, br), restorestack(L, cr));
      }
    }
  }
  
  
  
  /*
  ** 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);
          Table *h;
          Protect(h = luaH_new(L, luaO_fb2int(b), luaO_fb2int(c)));
          sethvalue(L, RA(i), h);
          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_lnumdiv, TM_DIV);
          continue;
        }
        case OP_MOD: {
          arith_op(luai_lnummod, 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: 
            case LUA_TROTABLE: {
              setnvalue(ra, ttistable(rb) ? cast_num(luaH_getn(hvalue(rb))) : cast_num(luaH_getn_ro(rvalue(rb))));
              break;
            }
            case LUA_TSTRING: {
              setnvalue(ra, cast_num(tsvalue(rb)->len));
              break;
            }
            default: {  /* try metamethod */
              ptrdiff_t br = savestack(L, rb);
              Protect(
                if (!call_binTM(L, rb, luaO_nilobject, ra, TM_LEN))
                  luaG_typeerror(L, restorestack(L, br), "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;
          fixedstack(L);
          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);
          }
          unfixedstack(L);
          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;
          fixedstack(L);
          ncl = luaF_newLclosure(L, nup, cl->env);
          setclvalue(L, ra, ncl);
          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));
            }
          }
          unfixedstack(L);
          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;
        }
      }
    }
  }
  
  