/*
** $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"
#include "llex.h"
#include "lnum.h"

/* limit for table tag-method chains (to avoid loops) */
#define MAXTAGLOOP	100

#ifdef __GNUC__
#define COMPUTED_GOTO 1
#endif

/*
 * If 'obj' is a string, it is tried to be interpreted as a number.
 */
const TValue *luaV_tonumber ( const TValue *obj, TValue *n) {
  lua_Number d;
  lua_Integer i;
  
  if (ttisnumber(obj)) return obj;

  if (ttisstring(obj)) {
    switch( luaO_str2d( svalue(obj), &d, &i ) ) {
        case TK_INT:
            setivalue(n,i); return n;
        case TK_NUMBER: 
            setnvalue(n,d); return n;
#ifdef LNUM_COMPLEX
        case TK_NUMBER2:    /* "N.NNNi", != 0 */
            setnvalue_complex_fast(n, d*I); return n;
#endif
        }
    }
  return NULL;
}


int luaV_tostring (lua_State *L, StkId obj) {
  if (!ttisnumber(obj))
    return 0;
  else {
    char s[LUAI_MAXNUMBER2STR];
    luaO_num2buf(s,obj);
    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;
    }
  }
}


#ifdef LNUM_COMPLEX
void error_complex( lua_State *L, const TValue *l, const TValue *r )
{
  char buf1[ LUAI_MAXNUMBER2STR ];
  char buf2[ LUAI_MAXNUMBER2STR ];
  luaO_num2buf( buf1, l );
  luaO_num2buf( buf2, r );
  luaG_runerror( L, "unable to compare: %s with %s", buf1, buf2 );
  /* no return */
}
#endif


int luaV_lessthan (lua_State *L, const TValue *l, const TValue *r) {
  int res;
  int tl,tr;
  lua_Integer tmp;

  if (!ttype_ext_same(l,r))
    return luaG_ordererror(L, l, r);
#ifdef LNUM_COMPLEX
  if ( (nvalue_img(l)!=0) || (nvalue_img(r)!=0) )
    error_complex( L, l, r );
#endif
  tl= ttype(l); tr= ttype(r);
  if (tl==tr) {  /* clear arithmetics */
    switch(tl) {
      case LUA_TINT:      return ivalue(l) < ivalue(r);
      case LUA_TNUMBER:   return luai_numlt(nvalue_fast(l), nvalue_fast(r));
      case LUA_TSTRING:   return l_strcmp(rawtsvalue(l), rawtsvalue(r)) < 0;
    }
  } else if (tl==LUA_TINT) {  /* l:int, r:num */
    /* Avoid accuracy losing casts: if 'r' is integer by value, do comparisons
     * in integer realm. Only otherwise cast 'l' to FP (which might change its
     * value).
     */
    if (tt_integer_valued(r,&tmp)) 
        return ivalue(l) < tmp;
    else 
        return luai_numlt( cast_num(ivalue(l)), nvalue_fast(r) );

  } else if (tl==LUA_TNUMBER) {  /* l:num, r:int */
    if (tt_integer_valued(l,&tmp)) 
        return tmp < ivalue(r);
    else
        return luai_numlt( nvalue_fast(l), cast_num(ivalue(r)) );

  } 
  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;
  int tl, tr;
  lua_Integer tmp;

  if (!ttype_ext_same(l,r))
    return luaG_ordererror(L, l, r);
#ifdef LNUM_COMPLEX
  if ( (nvalue_img(l)!=0) || (nvalue_img(r)!=0) )
    error_complex( L, l, r );
#endif
  tl= ttype(l); tr= ttype(r);
  if (tl==tr) {  /* clear arithmetics */
    switch(tl) {
      case LUA_TINT:      return ivalue(l) <= ivalue(r);
      case LUA_TNUMBER:   return luai_numle(nvalue_fast(l), nvalue_fast(r));
      case LUA_TSTRING:   return l_strcmp(rawtsvalue(l), rawtsvalue(r)) <= 0;
    }
  }
  if (tl==LUA_TINT) {  /* l:int, r:num */
    if (tt_integer_valued(r,&tmp)) 
        return ivalue(l) <= tmp;
    else
        return luai_numle( cast_num(ivalue(l)), nvalue_fast(r) );

  } else if (tl==LUA_TNUMBER) {  /* l:num, r:int */
    if (tt_integer_valued(l,&tmp)) 
        return tmp <= ivalue(r);
    else
        return luai_numle( nvalue_fast(l), cast_num(ivalue(r)) );

  } 
  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);
}


/* Note: 'luaV_equalval()' and 'luaO_rawequalObj()' have largely overlapping
 *       implementation. LUA_TNIL..LUA_TLIGHTUSERDATA cases could be handled
 *       simply by the 'default' case here.
 */
int luaV_equalval (lua_State *L, const TValue *l, const TValue *r) {
  const TValue *tm;
  lua_assert(ttype_ext_same(l,r));
  switch (ttype(l)) {
    case LUA_TNIL: return 1;
    case LUA_TINT:
    case LUA_TNUMBER: return luaO_rawequalObj(l,r);
    case LUA_TBOOLEAN: return bvalue(l) == bvalue(r);  /* true must be 1 !! */
    case LUA_TLIGHTUSERDATA: return pvalue(l) == pvalue(r);
    case LUA_TUSERDATA: {
      if (uvalue(l) == uvalue(r)) return 1;
      tm = get_compTM(L, uvalue(l)->metatable, uvalue(r)->metatable, TM_EQ);
      break;  /* will try TM */
    }
    case LUA_TTABLE: {
      if (hvalue(l) == hvalue(r)) return 1;
      tm = get_compTM(L, hvalue(l)->metatable, hvalue(r)->metatable, TM_EQ);
      break;  /* will try TM */
    }
    default: return gcvalue(l) == gcvalue(r);
  }
  if (tm == NULL) return 0;  /* no TM? */
  callTMres(L, L->top, tm, l, r);  /* 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 */
}


/*
** 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; }


/* Note: if called for unary operations, 'rc'=='rb'.
 */
static void Arith (lua_State *L, StkId ra, const TValue *rb,
                   const TValue *rc, TMS op) {
  TValue tempb, tempc;
  const TValue *b, *c;
  lua_Number nb,nc;

  if ((b = luaV_tonumber(rb, &tempb)) != NULL &&
      (c = luaV_tonumber(rc, &tempc)) != NULL) {

    /* Keep integer arithmetics in the integer realm, if possible.
     */
    if (ttisint(b) && ttisint(c)) {
      lua_Integer ib = ivalue(b), ic = ivalue(c);
      lua_Integer *ri = &ra->value.i;
      ra->tt= LUA_TINT;  /* part of 'setivalue(ra)' */
      switch (op) {
        case TM_ADD: if (try_addint( ri, ib, ic)) return; break;
        case TM_SUB: if (try_subint( ri, ib, ic)) return; break;
        case TM_MUL: if (try_mulint( ri, ib, ic)) return; break;
        case TM_DIV: if (try_divint( ri, ib, ic)) return; break;
        case TM_MOD: if (try_modint( ri, ib, ic)) return; break;
        case TM_POW: if (try_powint( ri, ib, ic)) return; break;
        case TM_UNM: if (try_unmint( ri, ib)) return; break;
        default: lua_assert(0);
      }
    }
    /* Fallback to floating point, when leaving range. */

#ifdef LNUM_COMPLEX
    if ((nvalue_img(b)!=0) || (nvalue_img(c)!=0)) {
      lua_Complex r;
      if (op==TM_UNM) {
        r= -nvalue_complex_fast(b);     /* never an integer (or scalar) */
        setnvalue_complex_fast( ra, r );
      } else {
        lua_Complex bb= nvalue_complex(b), cc= nvalue_complex(c);
        switch (op) {
          case TM_ADD: r= bb + cc; break;
          case TM_SUB: r= bb - cc; break;
          case TM_MUL: r= bb * cc; break;
          case TM_DIV: r= bb / cc; break;
          case TM_MOD: 
            luaG_runerror(L, "attempt to use %% on complex numbers");  /* no return */
          case TM_POW: r= luai_vectpow( bb, cc ); break;
          default: lua_assert(0); r=0;
        }
        setnvalue_complex( ra, r );
      }
      return;
    }
#endif
    nb = nvalue(b); nc = nvalue(c);
    switch (op) {
      case TM_ADD: setnvalue(ra, luai_numadd(nb, nc)); return;
      case TM_SUB: setnvalue(ra, luai_numsub(nb, nc)); return;
      case TM_MUL: setnvalue(ra, luai_nummul(nb, nc)); return;
      case TM_DIV: setnvalue(ra, luai_numdiv(nb, nc)); return;
      case TM_MOD: setnvalue(ra, luai_nummod(nb, nc)); return;
      case TM_POW: setnvalue(ra, luai_numpow(nb, nc)); return;
      case TM_UNM: setnvalue(ra, luai_numunm(nb)); return;
      default: lua_assert(0);
    }
  }
  
  /* Either operand not a number */
  if (!call_binTM(L, rb, rc, ra, op))
    luaG_aritherror(L, rb, rc);
}

/* Helper macro to sort arithmetic operations into four categories:
 *  TK_INT: integer - integer operands
 *  TK_NUMBER: number - number (non complex, either may be integer)
 *  TK_NUMBER2: complex numbers (at least the other)
 *  0: non-numeric (at least the other)
*/
#ifdef LNUM_COMPLEX
static inline int arith_mode( const TValue *rb, const TValue *rc ) {
  if (ttisint(rb) && ttisint(rc)) return TK_INT;
  if (ttiscomplex(rb) || ttiscomplex(rc)) return TK_NUMBER2;
  if (ttisnumber(rb) && ttisnumber(rc)) return TK_NUMBER;
  return 0;
}
#else
# define arith_mode(rb,rc) \
    ( (ttisint(rb) && ttisint(rc)) ? TK_INT : \
      (ttisnumber(rb) && ttisnumber(rc)) ? TK_NUMBER : 0 )
#endif

/* arith_op macro for two operators:
 * automatically chooses, which function (number, integer, complex) to use
 */
#define ARITH_OP2_START( op_num, op_int ) \
  int failed= 0; \
  switch( arith_mode(rb,rc) ) { \
    case TK_INT: \
      if (op_int ( &(ra)->value.i, ivalue(rb), ivalue(rc) )) \
        { ra->tt= LUA_TINT; break; } /* else flow through */ \
    case TK_NUMBER: \
      setnvalue(ra, op_num ( nvalue(rb), nvalue(rc) )); break;

#define ARITH_OP2_END \
    default: \
      failed= 1; break; \
  } if (!failed) continue;

#define arith_op_continue_scalar( op_num, op_int ) \
    ARITH_OP2_START( op_num, op_int ) \
    ARITH_OP2_END

#ifdef LNUM_COMPLEX
# define arith_op_continue( op_num, op_int, op_complex ) \
    ARITH_OP2_START( op_num, op_int ) \
      case TK_NUMBER2: \
        setnvalue_complex( ra, op_complex ( nvalue_complex(rb), nvalue_complex(rc) ) ); break; \
    ARITH_OP2_END
#else
# define arith_op_continue(op_num,op_int,_) arith_op_continue_scalar(op_num,op_int)
#endif

/* arith_op macro for one operator:
 */
#define ARITH_OP1_START( op_num, op_int ) \
  int failed= 0; \
  switch( arith_mode(rb,rb) ) { \
    case TK_INT: \
      if (op_int ( &(ra)->value.i, ivalue(rb) )) \
        { ra->tt= LUA_TINT; break; } /* else flow through */ \
      case TK_NUMBER: \
        setnvalue(ra, op_num (nvalue(rb))); break; \

#define ARITH_OP1_END \
      default: \
        failed= 1; break; \
  } if (!failed) continue;

#ifdef LNUM_COMPLEX
# define arith_op1_continue( op_num, op_int, op_complex ) \
    ARITH_OP1_START( op_num, op_int ) \
      case TK_NUMBER2: \
        setnvalue_complex( ra, op_complex ( nvalue_complex_fast(rb) )); break; \
    ARITH_OP1_END
#else
# define arith_op1_continue( op_num, op_int, _ ) \
    ARITH_OP1_START( op_num, op_int ) \
    ARITH_OP1_END
#endif

#ifdef COMPUTED_GOTO
#define OPCODE_TARGET(op) DO_OP_##op:
#define CALL_OPCODE(op) goto *opcodes[op];
#define OPCODE_PTR(op) [OP_##op] = &&DO_OP_##op
#else
#define OPCODE_TARGET(op) case OP_##op:
#define CALL_OPCODE(op) switch (op)
#endif


void luaV_execute (lua_State *L, int nexeccalls) {
  LClosure *cl;
  StkId base;
  TValue *k;
  const Instruction *pc;
#ifdef COMPUTED_GOTO
  static const void *opcodes[] = {
   OPCODE_PTR(MOVE),
   OPCODE_PTR(LOADK),
   OPCODE_PTR(LOADBOOL),
   OPCODE_PTR(LOADNIL),
   OPCODE_PTR(GETUPVAL),
   OPCODE_PTR(GETGLOBAL),
   OPCODE_PTR(GETTABLE),
   OPCODE_PTR(SETGLOBAL),
   OPCODE_PTR(SETUPVAL),
   OPCODE_PTR(SETTABLE),
   OPCODE_PTR(NEWTABLE),
   OPCODE_PTR(SELF),
   OPCODE_PTR(ADD),
   OPCODE_PTR(SUB),
   OPCODE_PTR(MUL),
   OPCODE_PTR(DIV),
   OPCODE_PTR(MOD),
   OPCODE_PTR(POW),
   OPCODE_PTR(UNM),
   OPCODE_PTR(NOT),
   OPCODE_PTR(LEN),
   OPCODE_PTR(CONCAT),
   OPCODE_PTR(JMP),
   OPCODE_PTR(EQ),
   OPCODE_PTR(LT),
   OPCODE_PTR(LE),
   OPCODE_PTR(TEST),
   OPCODE_PTR(TESTSET),
   OPCODE_PTR(CALL),
   OPCODE_PTR(TAILCALL),
   OPCODE_PTR(RETURN),
   OPCODE_PTR(FORLOOP),
   OPCODE_PTR(FORPREP),
   OPCODE_PTR(TFORLOOP),
   OPCODE_PTR(SETLIST),
   OPCODE_PTR(CLOSE),
   OPCODE_PTR(CLOSURE),
   OPCODE_PTR(VARARG)
  };
#endif
 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));
    CALL_OPCODE(GET_OPCODE(i)) {
      OPCODE_TARGET(MOVE) {
        setobjs2s(L, ra, RB(i));
        continue;
      }
      OPCODE_TARGET(LOADK) {
        setobj2s(L, ra, KBx(i));
        continue;
      }
      OPCODE_TARGET(LOADBOOL) {
        setbvalue(ra, GETARG_B(i));
        if (GETARG_C(i)) pc++;  /* skip next instruction (if C) */
        continue;
      }
      OPCODE_TARGET(LOADNIL) {
        TValue *rb = RB(i);
        do {
          setnilvalue(rb--);
        } while (rb >= ra);
        continue;
      }
      OPCODE_TARGET(GETUPVAL) {
        int b = GETARG_B(i);
        setobj2s(L, ra, cl->upvals[b]->v);
        continue;
      }
      OPCODE_TARGET(GETGLOBAL) {
        TValue g;
        TValue *rb = KBx(i);
        sethvalue(L, &g, cl->env);
        lua_assert(ttisstring(rb));
        Protect(luaV_gettable(L, &g, rb, ra));
        continue;
      }
      OPCODE_TARGET(GETTABLE) {
        Protect(luaV_gettable(L, RB(i), RKC(i), ra));
        continue;
      }
      OPCODE_TARGET(SETGLOBAL) {
        TValue g;
        sethvalue(L, &g, cl->env);
        lua_assert(ttisstring(KBx(i)));
        Protect(luaV_settable(L, &g, KBx(i), ra));
        continue;
      }
      OPCODE_TARGET(SETUPVAL) {
        UpVal *uv = cl->upvals[GETARG_B(i)];
        setobj(L, uv->v, ra);
        luaC_barrier(L, uv, ra);
        continue;
      }
      OPCODE_TARGET(SETTABLE) {
        Protect(luaV_settable(L, ra, RKB(i), RKC(i)));
        continue;
      }
      OPCODE_TARGET(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;
      }
      OPCODE_TARGET(SELF) {
        StkId rb = RB(i);
        setobjs2s(L, ra+1, rb);
        Protect(luaV_gettable(L, rb, RKC(i), ra));
        continue;
      }
      OPCODE_TARGET(ADD) {
        TValue *rb = RKB(i), *rc= RKC(i);
        arith_op_continue( luai_numadd, try_addint, luai_vectadd );
        Protect(Arith(L, ra, rb, rc, TM_ADD)); \
        continue;
      }
      OPCODE_TARGET(SUB) {
        TValue *rb = RKB(i), *rc= RKC(i);
        arith_op_continue( luai_numsub, try_subint, luai_vectsub );
        Protect(Arith(L, ra, rb, rc, TM_SUB));
        continue;
      }
      OPCODE_TARGET(MUL) {
        TValue *rb = RKB(i), *rc= RKC(i);
        arith_op_continue(luai_nummul, try_mulint, luai_vectmul);
        Protect(Arith(L, ra, rb, rc, TM_MUL));
        continue;
      }
      OPCODE_TARGET(DIV) {
        TValue *rb = RKB(i), *rc= RKC(i);
        arith_op_continue(luai_numdiv, try_divint, luai_vectdiv);
        Protect(Arith(L, ra, rb, rc, TM_DIV));
        continue;
      }
      OPCODE_TARGET(MOD) {
        TValue *rb = RKB(i), *rc= RKC(i);
        arith_op_continue_scalar(luai_nummod, try_modint);  /* scalars only */
        Protect(Arith(L, ra, rb, rc, TM_MOD));
        continue;
      }
      OPCODE_TARGET(POW) {
        TValue *rb = RKB(i), *rc= RKC(i);
        arith_op_continue(luai_numpow, try_powint, luai_vectpow);
        Protect(Arith(L, ra, rb, rc, TM_POW));
        continue;
      }
      OPCODE_TARGET(UNM) {
        TValue *rb = RB(i);
        arith_op1_continue(luai_numunm, try_unmint, luai_vectunm);
        Protect(Arith(L, ra, rb, rb, TM_UNM));
        continue;
      }
      OPCODE_TARGET(NOT) {
        int res = l_isfalse(RB(i));  /* next assignment may change this value */
        setbvalue(ra, res);
        continue;
      }
      OPCODE_TARGET(LEN) {
        const TValue *rb = RB(i);
        switch (ttype(rb)) {
          case LUA_TTABLE: {
            setivalue(ra, luaH_getn(hvalue(rb)));
            break;
          }
          case LUA_TSTRING: {
            setivalue(ra, 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;
      }
      OPCODE_TARGET(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;
      }
      OPCODE_TARGET(JMP) {
        dojump(L, pc, GETARG_sBx(i));
        continue;
      }
      OPCODE_TARGET(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;
      }
      OPCODE_TARGET(LT) {
        Protect(
          if (luaV_lessthan(L, RKB(i), RKC(i)) == GETARG_A(i))
            dojump(L, pc, GETARG_sBx(*pc));
        )
        pc++;
        continue;
      }
      OPCODE_TARGET(LE) {
        Protect(
          if (lessequal(L, RKB(i), RKC(i)) == GETARG_A(i))
            dojump(L, pc, GETARG_sBx(*pc));
        )
        pc++;
        continue;
      }
      OPCODE_TARGET(TEST) {
        if (l_isfalse(ra) != GETARG_C(i))
          dojump(L, pc, GETARG_sBx(*pc));
        pc++;
        continue;
      }
      OPCODE_TARGET(TESTSET) {
        TValue *rb = RB(i);
        if (l_isfalse(rb) != GETARG_C(i)) {
          setobjs2s(L, ra, rb);
          dojump(L, pc, GETARG_sBx(*pc));
        }
        pc++;
        continue;
      }
      OPCODE_TARGET(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 */
          }
        }
      }
      OPCODE_TARGET(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 */
          }
        }
      }
      OPCODE_TARGET(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;
        }
      }
      OPCODE_TARGET(FORLOOP) {
        /* If start,step and limit are all integers, we don't need to check
         * against overflow in the looping.
         */
        if (ttisint(ra) && ttisint(ra+1) && ttisint(ra+2)) {
          lua_Integer step = ivalue(ra+2);
          lua_Integer idx = ivalue(ra) + step; /* increment index */
          lua_Integer limit = ivalue(ra+1);
          if (step > 0 ? (idx <= limit) : (limit <= idx)) {
            dojump(L, pc, GETARG_sBx(i));  /* jump back */
            setivalue(ra, idx);  /* update internal index... */
            setivalue(ra+3, idx);  /* ...and external index */
          }
        } else {
          /* non-integer looping (don't use 'nvalue_fast', some may be integer!) 
          */
          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;
      }
      OPCODE_TARGET(FORPREP) {
        const TValue *init = ra;
        const TValue *plimit = ra+1;
        const TValue *pstep = ra+2;
        L->savedpc = pc;  /* next steps may throw errors */
        /* Using same location for tonumber's both arguments, effectively does
         * in-place modification (string->number). */
        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");
        /* Step back one value (keep within integers if we can)
         */
        if (!( ttisint(ra) && ttisint(pstep) &&
               try_subint( &ra->value.i, ivalue(ra), ivalue(pstep) ) )) {
            /* don't use 'nvalue_fast()', values may be integer */
            setnvalue(ra, luai_numsub(nvalue(ra), nvalue(pstep)));
        }
        dojump(L, pc, GETARG_sBx(i));
        continue;
      }
      OPCODE_TARGET(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;
      }
      OPCODE_TARGET(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_setint(L, h, last--), val);
          luaC_barriert(L, h, val);
        }
        continue;
      }
      OPCODE_TARGET(CLOSE) {
        luaF_close(L, ra);
        continue;
      }
      OPCODE_TARGET(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;
      }
      OPCODE_TARGET(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;
      }
    }
  }
}