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/script_binding/lua/lua/lvm.c

http://ftk.googlecode.com/
C | 763 lines | 686 code | 56 blank | 21 comment | 182 complexity | 009df5dea34190295d8b3c79d6910cc3 MD5 | raw file
  1/*
  2** $Id: lvm.c,v 2.63.1.3 2007/12/28 15:32:23 roberto Exp $
  3** Lua virtual machine
  4** See Copyright Notice in lua.h
  5*/
  6
  7
  8#include <stdio.h>
  9#include <stdlib.h>
 10#include <string.h>
 11
 12#define lvm_c
 13#define LUA_CORE
 14
 15#include "lua.h"
 16
 17#include "ldebug.h"
 18#include "ldo.h"
 19#include "lfunc.h"
 20#include "lgc.h"
 21#include "lobject.h"
 22#include "lopcodes.h"
 23#include "lstate.h"
 24#include "lstring.h"
 25#include "ltable.h"
 26#include "ltm.h"
 27#include "lvm.h"
 28
 29
 30
 31/* limit for table tag-method chains (to avoid loops) */
 32#define MAXTAGLOOP	100
 33
 34
 35const TValue *luaV_tonumber (const TValue *obj, TValue *n) {
 36  lua_Number num;
 37  if (ttisnumber(obj)) return obj;
 38  if (ttisstring(obj) && luaO_str2d(svalue(obj), &num)) {
 39    setnvalue(n, num);
 40    return n;
 41  }
 42  else
 43    return NULL;
 44}
 45
 46
 47int luaV_tostring (lua_State *L, StkId obj) {
 48  if (!ttisnumber(obj))
 49    return 0;
 50  else {
 51    char s[LUAI_MAXNUMBER2STR];
 52    lua_Number n = nvalue(obj);
 53    lua_number2str(s, n);
 54    setsvalue2s(L, obj, luaS_new(L, s));
 55    return 1;
 56  }
 57}
 58
 59
 60static void traceexec (lua_State *L, const Instruction *pc) {
 61  lu_byte mask = L->hookmask;
 62  const Instruction *oldpc = L->savedpc;
 63  L->savedpc = pc;
 64  if ((mask & LUA_MASKCOUNT) && L->hookcount == 0) {
 65    resethookcount(L);
 66    luaD_callhook(L, LUA_HOOKCOUNT, -1);
 67  }
 68  if (mask & LUA_MASKLINE) {
 69    Proto *p = ci_func(L->ci)->l.p;
 70    int npc = pcRel(pc, p);
 71    int newline = getline(p, npc);
 72    /* call linehook when enter a new function, when jump back (loop),
 73       or when enter a new line */
 74    if (npc == 0 || pc <= oldpc || newline != getline(p, pcRel(oldpc, p)))
 75      luaD_callhook(L, LUA_HOOKLINE, newline);
 76  }
 77}
 78
 79
 80static void callTMres (lua_State *L, StkId res, const TValue *f,
 81                        const TValue *p1, const TValue *p2) {
 82  ptrdiff_t result = savestack(L, res);
 83  setobj2s(L, L->top, f);  /* push function */
 84  setobj2s(L, L->top+1, p1);  /* 1st argument */
 85  setobj2s(L, L->top+2, p2);  /* 2nd argument */
 86  luaD_checkstack(L, 3);
 87  L->top += 3;
 88  luaD_call(L, L->top - 3, 1);
 89  res = restorestack(L, result);
 90  L->top--;
 91  setobjs2s(L, res, L->top);
 92}
 93
 94
 95
 96static void callTM (lua_State *L, const TValue *f, const TValue *p1,
 97                    const TValue *p2, const TValue *p3) {
 98  setobj2s(L, L->top, f);  /* push function */
 99  setobj2s(L, L->top+1, p1);  /* 1st argument */
100  setobj2s(L, L->top+2, p2);  /* 2nd argument */
101  setobj2s(L, L->top+3, p3);  /* 3th argument */
102  luaD_checkstack(L, 4);
103  L->top += 4;
104  luaD_call(L, L->top - 4, 0);
105}
106
107
108void luaV_gettable (lua_State *L, const TValue *t, TValue *key, StkId val) {
109  int loop;
110  for (loop = 0; loop < MAXTAGLOOP; loop++) {
111    const TValue *tm;
112    if (ttistable(t)) {  /* `t' is a table? */
113      Table *h = hvalue(t);
114      const TValue *res = luaH_get(h, key); /* do a primitive get */
115      if (!ttisnil(res) ||  /* result is no nil? */
116          (tm = fasttm(L, h->metatable, TM_INDEX)) == NULL) { /* or no TM? */
117        setobj2s(L, val, res);
118        return;
119      }
120      /* else will try the tag method */
121    }
122    else if (ttisnil(tm = luaT_gettmbyobj(L, t, TM_INDEX)))
123      luaG_typeerror(L, t, "index");
124    if (ttisfunction(tm)) {
125      callTMres(L, val, tm, t, key);
126      return;
127    }
128    t = tm;  /* else repeat with `tm' */ 
129  }
130  luaG_runerror(L, "loop in gettable");
131}
132
133
134void luaV_settable (lua_State *L, const TValue *t, TValue *key, StkId val) {
135  int loop;
136  for (loop = 0; loop < MAXTAGLOOP; loop++) {
137    const TValue *tm;
138    if (ttistable(t)) {  /* `t' is a table? */
139      Table *h = hvalue(t);
140      TValue *oldval = luaH_set(L, h, key); /* do a primitive set */
141      if (!ttisnil(oldval) ||  /* result is no nil? */
142          (tm = fasttm(L, h->metatable, TM_NEWINDEX)) == NULL) { /* or no TM? */
143        setobj2t(L, oldval, val);
144        luaC_barriert(L, h, val);
145        return;
146      }
147      /* else will try the tag method */
148    }
149    else if (ttisnil(tm = luaT_gettmbyobj(L, t, TM_NEWINDEX)))
150      luaG_typeerror(L, t, "index");
151    if (ttisfunction(tm)) {
152      callTM(L, tm, t, key, val);
153      return;
154    }
155    t = tm;  /* else repeat with `tm' */ 
156  }
157  luaG_runerror(L, "loop in settable");
158}
159
160
161static int call_binTM (lua_State *L, const TValue *p1, const TValue *p2,
162                       StkId res, TMS event) {
163  const TValue *tm = luaT_gettmbyobj(L, p1, event);  /* try first operand */
164  if (ttisnil(tm))
165    tm = luaT_gettmbyobj(L, p2, event);  /* try second operand */
166  if (ttisnil(tm)) return 0;
167  callTMres(L, res, tm, p1, p2);
168  return 1;
169}
170
171
172static const TValue *get_compTM (lua_State *L, Table *mt1, Table *mt2,
173                                  TMS event) {
174  const TValue *tm1 = fasttm(L, mt1, event);
175  const TValue *tm2;
176  if (tm1 == NULL) return NULL;  /* no metamethod */
177  if (mt1 == mt2) return tm1;  /* same metatables => same metamethods */
178  tm2 = fasttm(L, mt2, event);
179  if (tm2 == NULL) return NULL;  /* no metamethod */
180  if (luaO_rawequalObj(tm1, tm2))  /* same metamethods? */
181    return tm1;
182  return NULL;
183}
184
185
186static int call_orderTM (lua_State *L, const TValue *p1, const TValue *p2,
187                         TMS event) {
188  const TValue *tm1 = luaT_gettmbyobj(L, p1, event);
189  const TValue *tm2;
190  if (ttisnil(tm1)) return -1;  /* no metamethod? */
191  tm2 = luaT_gettmbyobj(L, p2, event);
192  if (!luaO_rawequalObj(tm1, tm2))  /* different metamethods? */
193    return -1;
194  callTMres(L, L->top, tm1, p1, p2);
195  return !l_isfalse(L->top);
196}
197
198
199static int l_strcmp (const TString *ls, const TString *rs) {
200  const char *l = getstr(ls);
201  size_t ll = ls->tsv.len;
202  const char *r = getstr(rs);
203  size_t lr = rs->tsv.len;
204  for (;;) {
205    int temp = strcoll(l, r);
206    if (temp != 0) return temp;
207    else {  /* strings are equal up to a `\0' */
208      size_t len = strlen(l);  /* index of first `\0' in both strings */
209      if (len == lr)  /* r is finished? */
210        return (len == ll) ? 0 : 1;
211      else if (len == ll)  /* l is finished? */
212        return -1;  /* l is smaller than r (because r is not finished) */
213      /* both strings longer than `len'; go on comparing (after the `\0') */
214      len++;
215      l += len; ll -= len; r += len; lr -= len;
216    }
217  }
218}
219
220
221int luaV_lessthan (lua_State *L, const TValue *l, const TValue *r) {
222  int res;
223  if (ttype(l) != ttype(r))
224    return luaG_ordererror(L, l, r);
225  else if (ttisnumber(l))
226    return luai_numlt(nvalue(l), nvalue(r));
227  else if (ttisstring(l))
228    return l_strcmp(rawtsvalue(l), rawtsvalue(r)) < 0;
229  else if ((res = call_orderTM(L, l, r, TM_LT)) != -1)
230    return res;
231  return luaG_ordererror(L, l, r);
232}
233
234
235static int lessequal (lua_State *L, const TValue *l, const TValue *r) {
236  int res;
237  if (ttype(l) != ttype(r))
238    return luaG_ordererror(L, l, r);
239  else if (ttisnumber(l))
240    return luai_numle(nvalue(l), nvalue(r));
241  else if (ttisstring(l))
242    return l_strcmp(rawtsvalue(l), rawtsvalue(r)) <= 0;
243  else if ((res = call_orderTM(L, l, r, TM_LE)) != -1)  /* first try `le' */
244    return res;
245  else if ((res = call_orderTM(L, r, l, TM_LT)) != -1)  /* else try `lt' */
246    return !res;
247  return luaG_ordererror(L, l, r);
248}
249
250
251int luaV_equalval (lua_State *L, const TValue *t1, const TValue *t2) {
252  const TValue *tm;
253  lua_assert(ttype(t1) == ttype(t2));
254  switch (ttype(t1)) {
255    case LUA_TNIL: return 1;
256    case LUA_TNUMBER: return luai_numeq(nvalue(t1), nvalue(t2));
257    case LUA_TBOOLEAN: return bvalue(t1) == bvalue(t2);  /* true must be 1 !! */
258    case LUA_TLIGHTUSERDATA: return pvalue(t1) == pvalue(t2);
259    case LUA_TUSERDATA: {
260      if (uvalue(t1) == uvalue(t2)) return 1;
261      tm = get_compTM(L, uvalue(t1)->metatable, uvalue(t2)->metatable,
262                         TM_EQ);
263      break;  /* will try TM */
264    }
265    case LUA_TTABLE: {
266      if (hvalue(t1) == hvalue(t2)) return 1;
267      tm = get_compTM(L, hvalue(t1)->metatable, hvalue(t2)->metatable, TM_EQ);
268      break;  /* will try TM */
269    }
270    default: return gcvalue(t1) == gcvalue(t2);
271  }
272  if (tm == NULL) return 0;  /* no TM? */
273  callTMres(L, L->top, tm, t1, t2);  /* call TM */
274  return !l_isfalse(L->top);
275}
276
277
278void luaV_concat (lua_State *L, int total, int last) {
279  do {
280    StkId top = L->base + last + 1;
281    int n = 2;  /* number of elements handled in this pass (at least 2) */
282    if (!(ttisstring(top-2) || ttisnumber(top-2)) || !tostring(L, top-1)) {
283      if (!call_binTM(L, top-2, top-1, top-2, TM_CONCAT))
284        luaG_concaterror(L, top-2, top-1);
285    } else if (tsvalue(top-1)->len == 0)  /* second op is empty? */
286      (void)tostring(L, top - 2);  /* result is first op (as string) */
287    else {
288      /* at least two string values; get as many as possible */
289      size_t tl = tsvalue(top-1)->len;
290      char *buffer;
291      int i;
292      /* collect total length */
293      for (n = 1; n < total && tostring(L, top-n-1); n++) {
294        size_t l = tsvalue(top-n-1)->len;
295        if (l >= MAX_SIZET - tl) luaG_runerror(L, "string length overflow");
296        tl += l;
297      }
298      buffer = luaZ_openspace(L, &G(L)->buff, tl);
299      tl = 0;
300      for (i=n; i>0; i--) {  /* concat all strings */
301        size_t l = tsvalue(top-i)->len;
302        memcpy(buffer+tl, svalue(top-i), l);
303        tl += l;
304      }
305      setsvalue2s(L, top-n, luaS_newlstr(L, buffer, tl));
306    }
307    total -= n-1;  /* got `n' strings to create 1 new */
308    last -= n-1;
309  } while (total > 1);  /* repeat until only 1 result left */
310}
311
312
313static void Arith (lua_State *L, StkId ra, const TValue *rb,
314                   const TValue *rc, TMS op) {
315  TValue tempb, tempc;
316  const TValue *b, *c;
317  if ((b = luaV_tonumber(rb, &tempb)) != NULL &&
318      (c = luaV_tonumber(rc, &tempc)) != NULL) {
319    lua_Number nb = nvalue(b), nc = nvalue(c);
320    switch (op) {
321      case TM_ADD: setnvalue(ra, luai_numadd(nb, nc)); break;
322      case TM_SUB: setnvalue(ra, luai_numsub(nb, nc)); break;
323      case TM_MUL: setnvalue(ra, luai_nummul(nb, nc)); break;
324      case TM_DIV: setnvalue(ra, luai_numdiv(nb, nc)); break;
325      case TM_MOD: setnvalue(ra, luai_nummod(nb, nc)); break;
326      case TM_POW: setnvalue(ra, luai_numpow(nb, nc)); break;
327      case TM_UNM: setnvalue(ra, luai_numunm(nb)); break;
328      default: lua_assert(0); break;
329    }
330  }
331  else if (!call_binTM(L, rb, rc, ra, op))
332    luaG_aritherror(L, rb, rc);
333}
334
335
336
337/*
338** some macros for common tasks in `luaV_execute'
339*/
340
341#define runtime_check(L, c)	{ if (!(c)) break; }
342
343#define RA(i)	(base+GETARG_A(i))
344/* to be used after possible stack reallocation */
345#define RB(i)	check_exp(getBMode(GET_OPCODE(i)) == OpArgR, base+GETARG_B(i))
346#define RC(i)	check_exp(getCMode(GET_OPCODE(i)) == OpArgR, base+GETARG_C(i))
347#define RKB(i)	check_exp(getBMode(GET_OPCODE(i)) == OpArgK, \
348	ISK(GETARG_B(i)) ? k+INDEXK(GETARG_B(i)) : base+GETARG_B(i))
349#define RKC(i)	check_exp(getCMode(GET_OPCODE(i)) == OpArgK, \
350	ISK(GETARG_C(i)) ? k+INDEXK(GETARG_C(i)) : base+GETARG_C(i))
351#define KBx(i)	check_exp(getBMode(GET_OPCODE(i)) == OpArgK, k+GETARG_Bx(i))
352
353
354#define dojump(L,pc,i)	{(pc) += (i); luai_threadyield(L);}
355
356
357#define Protect(x)	{ L->savedpc = pc; {x;}; base = L->base; }
358
359
360#define arith_op(op,tm) { \
361        TValue *rb = RKB(i); \
362        TValue *rc = RKC(i); \
363        if (ttisnumber(rb) && ttisnumber(rc)) { \
364          lua_Number nb = nvalue(rb), nc = nvalue(rc); \
365          setnvalue(ra, op(nb, nc)); \
366        } \
367        else \
368          Protect(Arith(L, ra, rb, rc, tm)); \
369      }
370
371
372
373void luaV_execute (lua_State *L, int nexeccalls) {
374  LClosure *cl;
375  StkId base;
376  TValue *k;
377  const Instruction *pc;
378 reentry:  /* entry point */
379  lua_assert(isLua(L->ci));
380  pc = L->savedpc;
381  cl = &clvalue(L->ci->func)->l;
382  base = L->base;
383  k = cl->p->k;
384  /* main loop of interpreter */
385  for (;;) {
386    const Instruction i = *pc++;
387    StkId ra;
388    if ((L->hookmask & (LUA_MASKLINE | LUA_MASKCOUNT)) &&
389        (--L->hookcount == 0 || L->hookmask & LUA_MASKLINE)) {
390      traceexec(L, pc);
391      if (L->status == LUA_YIELD) {  /* did hook yield? */
392        L->savedpc = pc - 1;
393        return;
394      }
395      base = L->base;
396    }
397    /* warning!! several calls may realloc the stack and invalidate `ra' */
398    ra = RA(i);
399    lua_assert(base == L->base && L->base == L->ci->base);
400    lua_assert(base <= L->top && L->top <= L->stack + L->stacksize);
401    lua_assert(L->top == L->ci->top || luaG_checkopenop(i));
402    switch (GET_OPCODE(i)) {
403      case OP_MOVE: {
404        setobjs2s(L, ra, RB(i));
405        continue;
406      }
407      case OP_LOADK: {
408        setobj2s(L, ra, KBx(i));
409        continue;
410      }
411      case OP_LOADBOOL: {
412        setbvalue(ra, GETARG_B(i));
413        if (GETARG_C(i)) pc++;  /* skip next instruction (if C) */
414        continue;
415      }
416      case OP_LOADNIL: {
417        TValue *rb = RB(i);
418        do {
419          setnilvalue(rb--);
420        } while (rb >= ra);
421        continue;
422      }
423      case OP_GETUPVAL: {
424        int b = GETARG_B(i);
425        setobj2s(L, ra, cl->upvals[b]->v);
426        continue;
427      }
428      case OP_GETGLOBAL: {
429        TValue g;
430        TValue *rb = KBx(i);
431        sethvalue(L, &g, cl->env);
432        lua_assert(ttisstring(rb));
433        Protect(luaV_gettable(L, &g, rb, ra));
434        continue;
435      }
436      case OP_GETTABLE: {
437        Protect(luaV_gettable(L, RB(i), RKC(i), ra));
438        continue;
439      }
440      case OP_SETGLOBAL: {
441        TValue g;
442        sethvalue(L, &g, cl->env);
443        lua_assert(ttisstring(KBx(i)));
444        Protect(luaV_settable(L, &g, KBx(i), ra));
445        continue;
446      }
447      case OP_SETUPVAL: {
448        UpVal *uv = cl->upvals[GETARG_B(i)];
449        setobj(L, uv->v, ra);
450        luaC_barrier(L, uv, ra);
451        continue;
452      }
453      case OP_SETTABLE: {
454        Protect(luaV_settable(L, ra, RKB(i), RKC(i)));
455        continue;
456      }
457      case OP_NEWTABLE: {
458        int b = GETARG_B(i);
459        int c = GETARG_C(i);
460        sethvalue(L, ra, luaH_new(L, luaO_fb2int(b), luaO_fb2int(c)));
461        Protect(luaC_checkGC(L));
462        continue;
463      }
464      case OP_SELF: {
465        StkId rb = RB(i);
466        setobjs2s(L, ra+1, rb);
467        Protect(luaV_gettable(L, rb, RKC(i), ra));
468        continue;
469      }
470      case OP_ADD: {
471        arith_op(luai_numadd, TM_ADD);
472        continue;
473      }
474      case OP_SUB: {
475        arith_op(luai_numsub, TM_SUB);
476        continue;
477      }
478      case OP_MUL: {
479        arith_op(luai_nummul, TM_MUL);
480        continue;
481      }
482      case OP_DIV: {
483        arith_op(luai_numdiv, TM_DIV);
484        continue;
485      }
486      case OP_MOD: {
487        arith_op(luai_nummod, TM_MOD);
488        continue;
489      }
490      case OP_POW: {
491        arith_op(luai_numpow, TM_POW);
492        continue;
493      }
494      case OP_UNM: {
495        TValue *rb = RB(i);
496        if (ttisnumber(rb)) {
497          lua_Number nb = nvalue(rb);
498          setnvalue(ra, luai_numunm(nb));
499        }
500        else {
501          Protect(Arith(L, ra, rb, rb, TM_UNM));
502        }
503        continue;
504      }
505      case OP_NOT: {
506        int res = l_isfalse(RB(i));  /* next assignment may change this value */
507        setbvalue(ra, res);
508        continue;
509      }
510      case OP_LEN: {
511        const TValue *rb = RB(i);
512        switch (ttype(rb)) {
513          case LUA_TTABLE: {
514            setnvalue(ra, cast_num(luaH_getn(hvalue(rb))));
515            break;
516          }
517          case LUA_TSTRING: {
518            setnvalue(ra, cast_num(tsvalue(rb)->len));
519            break;
520          }
521          default: {  /* try metamethod */
522            Protect(
523              if (!call_binTM(L, rb, luaO_nilobject, ra, TM_LEN))
524                luaG_typeerror(L, rb, "get length of");
525            )
526          }
527        }
528        continue;
529      }
530      case OP_CONCAT: {
531        int b = GETARG_B(i);
532        int c = GETARG_C(i);
533        Protect(luaV_concat(L, c-b+1, c); luaC_checkGC(L));
534        setobjs2s(L, RA(i), base+b);
535        continue;
536      }
537      case OP_JMP: {
538        dojump(L, pc, GETARG_sBx(i));
539        continue;
540      }
541      case OP_EQ: {
542        TValue *rb = RKB(i);
543        TValue *rc = RKC(i);
544        Protect(
545          if (equalobj(L, rb, rc) == GETARG_A(i))
546            dojump(L, pc, GETARG_sBx(*pc));
547        )
548        pc++;
549        continue;
550      }
551      case OP_LT: {
552        Protect(
553          if (luaV_lessthan(L, RKB(i), RKC(i)) == GETARG_A(i))
554            dojump(L, pc, GETARG_sBx(*pc));
555        )
556        pc++;
557        continue;
558      }
559      case OP_LE: {
560        Protect(
561          if (lessequal(L, RKB(i), RKC(i)) == GETARG_A(i))
562            dojump(L, pc, GETARG_sBx(*pc));
563        )
564        pc++;
565        continue;
566      }
567      case OP_TEST: {
568        if (l_isfalse(ra) != GETARG_C(i))
569          dojump(L, pc, GETARG_sBx(*pc));
570        pc++;
571        continue;
572      }
573      case OP_TESTSET: {
574        TValue *rb = RB(i);
575        if (l_isfalse(rb) != GETARG_C(i)) {
576          setobjs2s(L, ra, rb);
577          dojump(L, pc, GETARG_sBx(*pc));
578        }
579        pc++;
580        continue;
581      }
582      case OP_CALL: {
583        int b = GETARG_B(i);
584        int nresults = GETARG_C(i) - 1;
585        if (b != 0) L->top = ra+b;  /* else previous instruction set top */
586        L->savedpc = pc;
587        switch (luaD_precall(L, ra, nresults)) {
588          case PCRLUA: {
589            nexeccalls++;
590            goto reentry;  /* restart luaV_execute over new Lua function */
591          }
592          case PCRC: {
593            /* it was a C function (`precall' called it); adjust results */
594            if (nresults >= 0) L->top = L->ci->top;
595            base = L->base;
596            continue;
597          }
598          default: {
599            return;  /* yield */
600          }
601        }
602      }
603      case OP_TAILCALL: {
604        int b = GETARG_B(i);
605        if (b != 0) L->top = ra+b;  /* else previous instruction set top */
606        L->savedpc = pc;
607        lua_assert(GETARG_C(i) - 1 == LUA_MULTRET);
608        switch (luaD_precall(L, ra, LUA_MULTRET)) {
609          case PCRLUA: {
610            /* tail call: put new frame in place of previous one */
611            CallInfo *ci = L->ci - 1;  /* previous frame */
612            int aux;
613            StkId func = ci->func;
614            StkId pfunc = (ci+1)->func;  /* previous function index */
615            if (L->openupval) luaF_close(L, ci->base);
616            L->base = ci->base = ci->func + ((ci+1)->base - pfunc);
617            for (aux = 0; pfunc+aux < L->top; aux++)  /* move frame down */
618              setobjs2s(L, func+aux, pfunc+aux);
619            ci->top = L->top = func+aux;  /* correct top */
620            lua_assert(L->top == L->base + clvalue(func)->l.p->maxstacksize);
621            ci->savedpc = L->savedpc;
622            ci->tailcalls++;  /* one more call lost */
623            L->ci--;  /* remove new frame */
624            goto reentry;
625          }
626          case PCRC: {  /* it was a C function (`precall' called it) */
627            base = L->base;
628            continue;
629          }
630          default: {
631            return;  /* yield */
632          }
633        }
634      }
635      case OP_RETURN: {
636        int b = GETARG_B(i);
637        if (b != 0) L->top = ra+b-1;
638        if (L->openupval) luaF_close(L, base);
639        L->savedpc = pc;
640        b = luaD_poscall(L, ra);
641        if (--nexeccalls == 0)  /* was previous function running `here'? */
642          return;  /* no: return */
643        else {  /* yes: continue its execution */
644          if (b) L->top = L->ci->top;
645          lua_assert(isLua(L->ci));
646          lua_assert(GET_OPCODE(*((L->ci)->savedpc - 1)) == OP_CALL);
647          goto reentry;
648        }
649      }
650      case OP_FORLOOP: {
651        lua_Number step = nvalue(ra+2);
652        lua_Number idx = luai_numadd(nvalue(ra), step); /* increment index */
653        lua_Number limit = nvalue(ra+1);
654        if (luai_numlt(0, step) ? luai_numle(idx, limit)
655                                : luai_numle(limit, idx)) {
656          dojump(L, pc, GETARG_sBx(i));  /* jump back */
657          setnvalue(ra, idx);  /* update internal index... */
658          setnvalue(ra+3, idx);  /* ...and external index */
659        }
660        continue;
661      }
662      case OP_FORPREP: {
663        const TValue *init = ra;
664        const TValue *plimit = ra+1;
665        const TValue *pstep = ra+2;
666        L->savedpc = pc;  /* next steps may throw errors */
667        if (!tonumber(init, ra))
668          luaG_runerror(L, LUA_QL("for") " initial value must be a number");
669        else if (!tonumber(plimit, ra+1))
670          luaG_runerror(L, LUA_QL("for") " limit must be a number");
671        else if (!tonumber(pstep, ra+2))
672          luaG_runerror(L, LUA_QL("for") " step must be a number");
673        setnvalue(ra, luai_numsub(nvalue(ra), nvalue(pstep)));
674        dojump(L, pc, GETARG_sBx(i));
675        continue;
676      }
677      case OP_TFORLOOP: {
678        StkId cb = ra + 3;  /* call base */
679        setobjs2s(L, cb+2, ra+2);
680        setobjs2s(L, cb+1, ra+1);
681        setobjs2s(L, cb, ra);
682        L->top = cb+3;  /* func. + 2 args (state and index) */
683        Protect(luaD_call(L, cb, GETARG_C(i)));
684        L->top = L->ci->top;
685        cb = RA(i) + 3;  /* previous call may change the stack */
686        if (!ttisnil(cb)) {  /* continue loop? */
687          setobjs2s(L, cb-1, cb);  /* save control variable */
688          dojump(L, pc, GETARG_sBx(*pc));  /* jump back */
689        }
690        pc++;
691        continue;
692      }
693      case OP_SETLIST: {
694        int n = GETARG_B(i);
695        int c = GETARG_C(i);
696        int last;
697        Table *h;
698        if (n == 0) {
699          n = cast_int(L->top - ra) - 1;
700          L->top = L->ci->top;
701        }
702        if (c == 0) c = cast_int(*pc++);
703        runtime_check(L, ttistable(ra));
704        h = hvalue(ra);
705        last = ((c-1)*LFIELDS_PER_FLUSH) + n;
706        if (last > h->sizearray)  /* needs more space? */
707          luaH_resizearray(L, h, last);  /* pre-alloc it at once */
708        for (; n > 0; n--) {
709          TValue *val = ra+n;
710          setobj2t(L, luaH_setnum(L, h, last--), val);
711          luaC_barriert(L, h, val);
712        }
713        continue;
714      }
715      case OP_CLOSE: {
716        luaF_close(L, ra);
717        continue;
718      }
719      case OP_CLOSURE: {
720        Proto *p;
721        Closure *ncl;
722        int nup, j;
723        p = cl->p->p[GETARG_Bx(i)];
724        nup = p->nups;
725        ncl = luaF_newLclosure(L, nup, cl->env);
726        ncl->l.p = p;
727        for (j=0; j<nup; j++, pc++) {
728          if (GET_OPCODE(*pc) == OP_GETUPVAL)
729            ncl->l.upvals[j] = cl->upvals[GETARG_B(*pc)];
730          else {
731            lua_assert(GET_OPCODE(*pc) == OP_MOVE);
732            ncl->l.upvals[j] = luaF_findupval(L, base + GETARG_B(*pc));
733          }
734        }
735        setclvalue(L, ra, ncl);
736        Protect(luaC_checkGC(L));
737        continue;
738      }
739      case OP_VARARG: {
740        int b = GETARG_B(i) - 1;
741        int j;
742        CallInfo *ci = L->ci;
743        int n = cast_int(ci->base - ci->func) - cl->p->numparams - 1;
744        if (b == LUA_MULTRET) {
745          Protect(luaD_checkstack(L, n));
746          ra = RA(i);  /* previous call may change the stack */
747          b = n;
748          L->top = ra + n;
749        }
750        for (j = 0; j < b; j++) {
751          if (j < n) {
752            setobjs2s(L, ra + j, ci->base - n + j);
753          }
754          else {
755            setnilvalue(ra + j);
756          }
757        }
758        continue;
759      }
760    }
761  }
762}
763