src/lvm.c

   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
  35 const 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
  47 int 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
  60 static 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
  80 static 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
  96 static 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
 108 void 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
 134 void 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       /* oldval is nil=> look for newindex, oldval is not nil => look for usedindex */
 142       if (!((ttisnil(oldval) && (tm = fasttm(L, h->metatable, TM_NEWINDEX))) ||
 143          ((!ttisnil(oldval)) && (tm = fasttm(L, h->metatable, TM_USEDINDEX))))) {
 144         setobj2t(L, oldval, val);
 145         luaC_barriert(L, h, val);
 146         return;
 147       }
 148       /* else will try the tag method */
 149     }
 150     else if (ttisnil(tm = luaT_gettmbyobj(L, t, TM_NEWINDEX)))
 151       luaG_typeerror(L, t, "index");
 152     if (ttisfunction(tm)) {
 153       callTM(L, tm, t, key, val);
 154       return;
 155     }
 156     t = tm;  /* else repeat with `tm' */
 157   }
 158   luaG_runerror(L, "loop in settable");
 159 }
 160
 161
 162 static int call_binTM (lua_State *L, const TValue *p1, const TValue *p2,
 163                        StkId res, TMS event) {
 164   const TValue *tm = luaT_gettmbyobj(L, p1, event);  /* try first operand */
 165   if (ttisnil(tm))
 166     tm = luaT_gettmbyobj(L, p2, event);  /* try second operand */
 167   if (ttisnil(tm)) return 0;
 168   callTMres(L, res, tm, p1, p2);
 169   return 1;
 170 }
 171
 172
 173 static const TValue *get_compTM (lua_State *L, Table *mt1, Table *mt2,
 174                                   TMS event) {
 175   const TValue *tm1 = fasttm(L, mt1, event);
 176   const TValue *tm2;
 177   if (tm1 == NULL) return NULL;  /* no metamethod */
 178   if (mt1 == mt2) return tm1;  /* same metatables => same metamethods */
 179   tm2 = fasttm(L, mt2, event);
 180   if (tm2 == NULL) return NULL;  /* no metamethod */
 181   if (luaO_rawequalObj(tm1, tm2))  /* same metamethods? */
 182     return tm1;
 183   return NULL;
 184 }
 185
 186
 187 static int call_orderTM (lua_State *L, const TValue *p1, const TValue *p2,
 188                          TMS event) {
 189   const TValue *tm1 = luaT_gettmbyobj(L, p1, event);
 190   const TValue *tm2;
 191   if (ttisnil(tm1)) return -1;  /* no metamethod? */
 192   tm2 = luaT_gettmbyobj(L, p2, event);
 193   if (!luaO_rawequalObj(tm1, tm2))  /* different metamethods? */
 194     return -1;
 195   callTMres(L, L->top, tm1, p1, p2);
 196   return !l_isfalse(L->top);
 197 }
 198
 199
 200 static int l_strcmp (const TString *ls, const TString *rs) {
 201   const char *l = getstr(ls);
 202   size_t ll = ls->tsv.len;
 203   const char *r = getstr(rs);
 204   size_t lr = rs->tsv.len;
 205   for (;;) {
 206     int temp = strcoll(l, r);
 207     if (temp != 0) return temp;
 208     else {  /* strings are equal up to a `\0' */
 209       size_t len = strlen(l);  /* index of first `\0' in both strings */
 210       if (len == lr)  /* r is finished? */
 211         return (len == ll) ? 0 : 1;
 212       else if (len == ll)  /* l is finished? */
 213         return -1;  /* l is smaller than r (because r is not finished) */
 214       /* both strings longer than `len'; go on comparing (after the `\0') */
 215       len++;
 216       l += len; ll -= len; r += len; lr -= len;
 217     }
 218   }
 219 }
 220
 221
 222 int luaV_lessthan (lua_State *L, const TValue *l, const TValue *r) {
 223   int res;
 224   if (ttype(l) != ttype(r))
 225     return luaG_ordererror(L, l, r);
 226   else if (ttisnumber(l))
 227     return luai_numlt(nvalue(l), nvalue(r));
 228   else if (ttisstring(l))
 229     return l_strcmp(rawtsvalue(l), rawtsvalue(r)) < 0;
 230   else if ((res = call_orderTM(L, l, r, TM_LT)) != -1)
 231     return res;
 232   return luaG_ordererror(L, l, r);
 233 }
 234
 235
 236 static int lessequal (lua_State *L, const TValue *l, const TValue *r) {
 237   int res;
 238   if (ttype(l) != ttype(r))
 239     return luaG_ordererror(L, l, r);
 240   else if (ttisnumber(l))
 241     return luai_numle(nvalue(l), nvalue(r));
 242   else if (ttisstring(l))
 243     return l_strcmp(rawtsvalue(l), rawtsvalue(r)) <= 0;
 244   else if ((res = call_orderTM(L, l, r, TM_LE)) != -1)  /* first try `le' */
 245     return res;
 246   else if ((res = call_orderTM(L, r, l, TM_LT)) != -1)  /* else try `lt' */
 247     return !res;
 248   return luaG_ordererror(L, l, r);
 249 }
 250
 251
 252 int luaV_equalval (lua_State *L, const TValue *t1, const TValue *t2) {
 253   const TValue *tm;
 254   lua_assert(ttype(t1) == ttype(t2));
 255   switch (ttype(t1)) {
 256     case LUA_TNIL: return 1;
 257     case LUA_TNUMBER: return luai_numeq(nvalue(t1), nvalue(t2));
 258     case LUA_TBOOLEAN: return bvalue(t1) == bvalue(t2);  /* true must be 1 !! */
 259     case LUA_TLIGHTUSERDATA: return pvalue(t1) == pvalue(t2);
 260     case LUA_TUSERDATA: {
 261       if (uvalue(t1) == uvalue(t2)) return 1;
 262       tm = get_compTM(L, uvalue(t1)->metatable, uvalue(t2)->metatable,
 263                          TM_EQ);
 264       break;  /* will try TM */
 265     }
 266     case LUA_TTABLE: {
 267       if (hvalue(t1) == hvalue(t2)) return 1;
 268       tm = get_compTM(L, hvalue(t1)->metatable, hvalue(t2)->metatable, TM_EQ);
 269       break;  /* will try TM */
 270     }
 271     default: return gcvalue(t1) == gcvalue(t2);
 272   }
 273   if (tm == NULL) return 0;  /* no TM? */
 274   callTMres(L, L->top, tm, t1, t2);  /* call TM */
 275   return !l_isfalse(L->top);
 276 }
 277
 278
 279 void luaV_concat (lua_State *L, int total, int last) {
 280   do {
 281     StkId top = L->base + last + 1;
 282     int n = 2;  /* number of elements handled in this pass (at least 2) */
 283     if (!(ttisstring(top-2) || ttisnumber(top-2)) || !tostring(L, top-1)) {
 284       if (!call_binTM(L, top-2, top-1, top-2, TM_CONCAT))
 285         luaG_concaterror(L, top-2, top-1);
 286     } else if (tsvalue(top-1)->len == 0)  /* second op is empty? */
 287       (void)tostring(L, top - 2);  /* result is first op (as string) */
 288     else {
 289       /* at least two string values; get as many as possible */
 290       size_t tl = tsvalue(top-1)->len;
 291       char *buffer;
 292       int i;
 293       /* collect total length */
 294       for (n = 1; n < total && tostring(L, top-n-1); n++) {
 295         size_t l = tsvalue(top-n-1)->len;
 296         if (l >= MAX_SIZET - tl) luaG_runerror(L, "string length overflow");
 297         tl += l;
 298       }
 299       buffer = luaZ_openspace(L, &G(L)->buff, tl);
 300       tl = 0;
 301       for (i=n; i>0; i--) {  /* concat all strings */
 302         size_t l = tsvalue(top-i)->len;
 303         memcpy(buffer+tl, svalue(top-i), l);
 304         tl += l;
 305       }
 306       setsvalue2s(L, top-n, luaS_newlstr(L, buffer, tl));
 307     }
 308     total -= n-1;  /* got `n' strings to create 1 new */
 309     last -= n-1;
 310   } while (total > 1);  /* repeat until only 1 result left */
 311 }
 312
 313
 314 static void Arith (lua_State *L, StkId ra, const TValue *rb,
 315                    const TValue *rc, TMS op) {
 316   TValue tempb, tempc;
 317   const TValue *b, *c;
 318   if ((b = luaV_tonumber(rb, &tempb)) != NULL &&
 319       (c = luaV_tonumber(rc, &tempc)) != NULL) {
 320     lua_Number nb = nvalue(b), nc = nvalue(c);
 321     switch (op) {
 322       case TM_ADD: setnvalue(ra, luai_numadd(nb, nc)); break;
 323       case TM_SUB: setnvalue(ra, luai_numsub(nb, nc)); break;
 324       case TM_MUL: setnvalue(ra, luai_nummul(nb, nc)); break;
 325       case TM_DIV: setnvalue(ra, luai_numdiv(nb, nc)); break;
 326       case TM_MOD: setnvalue(ra, luai_nummod(nb, nc)); break;
 327       case TM_POW: setnvalue(ra, luai_numpow(nb, nc)); break;
 328       case TM_UNM: setnvalue(ra, luai_numunm(nb)); break;
 329       case TM_AND: setnvalue(ra, luai_numand(nb, nc)); break;
 330       case TM_OR: setnvalue(ra, luai_numor(nb, nc)); break;
 331       case TM_XOR: setnvalue(ra, luai_numxor(nb, nc)); break;
 332       case TM_SHL: setnvalue(ra, luai_numshl(nb, nc)); break;
 333       case TM_SHR: setnvalue(ra, luai_numshr(nb, nc)); break;
 334       case TM_NOT: setnvalue(ra, luai_numnot(nb)); break;
 335       default: lua_assert(0); break;
 336     }
 337   }
 338   else if (!call_binTM(L, rb, rc, ra, op))
 339     luaG_aritherror(L, rb, rc);
 340 }
 341
 342
 343
 344 /*
 345 ** some macros for common tasks in `luaV_execute'
 346 */
 347
 348 #define runtime_check(L, c)     { if (!(c)) break; }
 349
 350 #define RA(i)   (base+GETARG_A(i))
 351 /* to be used after possible stack reallocation */
 352 #define RB(i)   check_exp(getBMode(GET_OPCODE(i)) == OpArgR, base+GETARG_B(i))
 353 #define RC(i)   check_exp(getCMode(GET_OPCODE(i)) == OpArgR, base+GETARG_C(i))
 354 #define RKB(i)  check_exp(getBMode(GET_OPCODE(i)) == OpArgK, \
 355         ISK(GETARG_B(i)) ? k+INDEXK(GETARG_B(i)) : base+GETARG_B(i))
 356 #define RKC(i)  check_exp(getCMode(GET_OPCODE(i)) == OpArgK, \
 357         ISK(GETARG_C(i)) ? k+INDEXK(GETARG_C(i)) : base+GETARG_C(i))
 358 #define KBx(i)  check_exp(getBMode(GET_OPCODE(i)) == OpArgK, k+GETARG_Bx(i))
 359
 360
 361 #define dojump(L,pc,i)  {(pc) += (i); luai_threadyield(L);}
 362
 363
 364 #define Protect(x)      { L->savedpc = pc; {x;}; base = L->base; }
 365
 366
 367 #define arith_op(op,tm) { \
 368         TValue *rb = RKB(i); \
 369         TValue *rc = RKC(i); \
 370         if (ttisnumber(rb) && ttisnumber(rc)) { \
 371           lua_Number nb = nvalue(rb), nc = nvalue(rc); \
 372           setnvalue(ra, op(nb, nc)); \
 373         } \
 374         else \
 375           Protect(Arith(L, ra, rb, rc, tm)); \
 376       }
 377
 378
 379
 380 void luaV_execute (lua_State *L, int nexeccalls) {
 381   LClosure *cl;
 382   StkId base;
 383   TValue *k;
 384   const Instruction *pc;
 385  reentry:  /* entry point */
 386   lua_assert(isLua(L->ci));
 387   pc = L->savedpc;
 388   cl = &clvalue(L->ci->func)->l;
 389   base = L->base;
 390   k = cl->p->k;
 391   /* main loop of interpreter */
 392   for (;;) {
 393     const Instruction i = *pc++;
 394     StkId ra;
 395     if ((L->hookmask & (LUA_MASKLINE | LUA_MASKCOUNT)) &&
 396         (--L->hookcount == 0 || L->hookmask & LUA_MASKLINE)) {
 397       traceexec(L, pc);
 398       if (L->status == LUA_YIELD) {  /* did hook yield? */
 399         L->savedpc = pc - 1;
 400         return;
 401       }
 402       base = L->base;
 403     }
 404     /* warning!! several calls may realloc the stack and invalidate `ra' */
 405     ra = RA(i);
 406     lua_assert(base == L->base && L->base == L->ci->base);
 407     lua_assert(base <= L->top && L->top <= L->stack + L->stacksize);
 408     lua_assert(L->top == L->ci->top || luaG_checkopenop(i));
 409     switch (GET_OPCODE(i)) {
 410       case OP_MOVE: {
 411         setobjs2s(L, ra, RB(i));
 412         continue;
 413       }
 414       case OP_LOADK: {
 415         setobj2s(L, ra, KBx(i));
 416         continue;
 417       }
 418       case OP_LOADBOOL: {
 419         setbvalue(ra, GETARG_B(i));
 420         if (GETARG_C(i)) pc++;  /* skip next instruction (if C) */
 421         continue;
 422       }
 423       case OP_LOADNIL: {
 424         TValue *rb = RB(i);
 425         do {
 426           setnilvalue(rb--);
 427         } while (rb >= ra);
 428         continue;
 429       }
 430       case OP_GETUPVAL: {
 431         int b = GETARG_B(i);
 432         setobj2s(L, ra, cl->upvals[b]->v);
 433         continue;
 434       }
 435       case OP_GETGLOBAL: {
 436         TValue g;
 437         TValue *rb = KBx(i);
 438         sethvalue(L, &g, cl->env);
 439         lua_assert(ttisstring(rb));
 440         Protect(luaV_gettable(L, &g, rb, ra));
 441         continue;
 442       }
 443       case OP_GETTABLE: {
 444         Protect(luaV_gettable(L, RB(i), RKC(i), ra));
 445         continue;
 446       }
 447       case OP_SETGLOBAL: {
 448         TValue g;
 449         sethvalue(L, &g, cl->env);
 450         lua_assert(ttisstring(KBx(i)));
 451         Protect(luaV_settable(L, &g, KBx(i), ra));
 452         continue;
 453       }
 454       case OP_SETUPVAL: {
 455         UpVal *uv = cl->upvals[GETARG_B(i)];
 456         setobj(L, uv->v, ra);
 457         luaC_barrier(L, uv, ra);
 458         continue;
 459       }
 460       case OP_SETTABLE: {
 461         Protect(luaV_settable(L, ra, RKB(i), RKC(i)));
 462         continue;
 463       }
 464       case OP_NEWTABLE: {
 465         int b = GETARG_B(i);
 466         int c = GETARG_C(i);
 467         sethvalue(L, ra, luaH_new(L, luaO_fb2int(b), luaO_fb2int(c)));
 468         Protect(luaC_checkGC(L));
 469         continue;
 470       }
 471       case OP_SELF: {
 472         StkId rb = RB(i);
 473         setobjs2s(L, ra+1, rb);
 474         Protect(luaV_gettable(L, rb, RKC(i), ra));
 475         continue;
 476       }
 477       case OP_ADD: {
 478         arith_op(luai_numadd, TM_ADD);
 479         continue;
 480       }
 481       case OP_SUB: {
 482         arith_op(luai_numsub, TM_SUB);
 483         continue;
 484       }
 485       case OP_MUL: {
 486         arith_op(luai_nummul, TM_MUL);
 487         continue;
 488       }
 489       case OP_DIV: {
 490         arith_op(luai_numdiv, TM_DIV);
 491         continue;
 492       }
 493       case OP_MOD: {
 494         arith_op(luai_nummod, TM_MOD);
 495         continue;
 496       }
 497       case OP_POW: {
 498         arith_op(luai_numpow, TM_POW);
 499         continue;
 500       }
 501       case OP_BAND: {
 502         arith_op(luai_numand, TM_AND);
 503         continue;
 504       }
 505       case OP_BOR: {
 506         arith_op(luai_numor, TM_OR);
 507         continue;
 508       }
 509       case OP_BXOR: {
 510         arith_op(luai_numxor, TM_XOR);
 511         continue;
 512       }
 513       case OP_BSHL: {
 514         arith_op(luai_numshl, TM_SHL);
 515         continue;
 516       }
 517       case OP_BSHR: {
 518         arith_op(luai_numshr, TM_SHR);
 519         continue;
 520       }
 521       case OP_BNOT: {
 522         TValue *rb = RB(i);
 523         if (ttisnumber(rb)) {
 524           lua_Number nb = nvalue(rb);
 525           setnvalue(ra, luai_numnot(nb));
 526         }
 527         else {
 528           Protect(Arith(L, ra, rb, rb, TM_NOT));
 529         }
 530         continue;
 531       }
 532       case OP_UNM: {
 533         TValue *rb = RB(i);
 534         if (ttisnumber(rb)) {
 535           lua_Number nb = nvalue(rb);
 536           setnvalue(ra, luai_numunm(nb));
 537         }
 538         else {
 539           Protect(Arith(L, ra, rb, rb, TM_UNM));
 540         }
 541         continue;
 542       }
 543       case OP_NOT: {
 544         int res = l_isfalse(RB(i));  /* next assignment may change this value */
 545         setbvalue(ra, res);
 546         continue;
 547       }
 548       case OP_LEN: {
 549         const TValue *rb = RB(i);
 550         switch (ttype(rb)) {
 551           case LUA_TTABLE: {
 552             setnvalue(ra, cast_num(luaH_getn(hvalue(rb))));
 553             break;
 554           }
 555           case LUA_TSTRING: {
 556             setnvalue(ra, cast_num(tsvalue(rb)->len));
 557             break;
 558           }
 559           default: {  /* try metamethod */
 560             Protect(
 561               if (!call_binTM(L, rb, luaO_nilobject, ra, TM_LEN))
 562                 luaG_typeerror(L, rb, "get length of");
 563             )
 564           }
 565         }
 566         continue;
 567       }
 568       case OP_CONCAT: {
 569         int b = GETARG_B(i);
 570         int c = GETARG_C(i);
 571         Protect(luaV_concat(L, c-b+1, c); luaC_checkGC(L));
 572         setobjs2s(L, RA(i), base+b);
 573         continue;
 574       }
 575       case OP_JMP: {
 576         dojump(L, pc, GETARG_sBx(i));
 577         continue;
 578       }
 579       case OP_EQ: {
 580         TValue *rb = RKB(i);
 581         TValue *rc = RKC(i);
 582         Protect(
 583           if (equalobj(L, rb, rc) == GETARG_A(i))
 584             dojump(L, pc, GETARG_sBx(*pc));
 585         )
 586         pc++;
 587         continue;
 588       }
 589       case OP_LT: {
 590         Protect(
 591           if (luaV_lessthan(L, RKB(i), RKC(i)) == GETARG_A(i))
 592             dojump(L, pc, GETARG_sBx(*pc));
 593         )
 594         pc++;
 595         continue;
 596       }
 597       case OP_LE: {
 598         Protect(
 599           if (lessequal(L, RKB(i), RKC(i)) == GETARG_A(i))
 600             dojump(L, pc, GETARG_sBx(*pc));
 601         )
 602         pc++;
 603         continue;
 604       }
 605       case OP_TEST: {
 606         if (l_isfalse(ra) != GETARG_C(i))
 607           dojump(L, pc, GETARG_sBx(*pc));
 608         pc++;
 609         continue;
 610       }
 611       case OP_TESTSET: {
 612         TValue *rb = RB(i);
 613         if (l_isfalse(rb) != GETARG_C(i)) {
 614           setobjs2s(L, ra, rb);
 615           dojump(L, pc, GETARG_sBx(*pc));
 616         }
 617         pc++;
 618         continue;
 619       }
 620       case OP_CALL: {
 621         int b = GETARG_B(i);
 622         int nresults = GETARG_C(i) - 1;
 623         if (b != 0) L->top = ra+b;  /* else previous instruction set top */
 624         L->savedpc = pc;
 625         switch (luaD_precall(L, ra, nresults)) {
 626           case PCRLUA: {
 627             nexeccalls++;
 628             goto reentry;  /* restart luaV_execute over new Lua function */
 629           }
 630           case PCRC: {
 631             /* it was a C function (`precall' called it); adjust results */
 632             if (nresults >= 0) L->top = L->ci->top;
 633             base = L->base;
 634             continue;
 635           }
 636           default: {
 637             return;  /* yield */
 638           }
 639         }
 640       }
 641       case OP_TAILCALL: {
 642         int b = GETARG_B(i);
 643         if (b != 0) L->top = ra+b;  /* else previous instruction set top */
 644         L->savedpc = pc;
 645         lua_assert(GETARG_C(i) - 1 == LUA_MULTRET);
 646         switch (luaD_precall(L, ra, LUA_MULTRET)) {
 647           case PCRLUA: {
 648             /* tail call: put new frame in place of previous one */
 649             CallInfo *ci = L->ci - 1;  /* previous frame */
 650             int aux;
 651             StkId func = ci->func;
 652             StkId pfunc = (ci+1)->func;  /* previous function index */
 653             if (L->openupval) luaF_close(L, ci->base);
 654             L->base = ci->base = ci->func + ((ci+1)->base - pfunc);
 655             for (aux = 0; pfunc+aux < L->top; aux++)  /* move frame down */
 656               setobjs2s(L, func+aux, pfunc+aux);
 657             ci->top = L->top = func+aux;  /* correct top */
 658             lua_assert(L->top == L->base + clvalue(func)->l.p->maxstacksize);
 659             ci->savedpc = L->savedpc;
 660             ci->tailcalls++;  /* one more call lost */
 661             L->ci--;  /* remove new frame */
 662             goto reentry;
 663           }
 664           case PCRC: {  /* it was a C function (`precall' called it) */
 665             base = L->base;
 666             continue;
 667           }
 668           default: {
 669             return;  /* yield */
 670           }
 671         }
 672       }
 673       case OP_RETURN: {
 674         int b = GETARG_B(i);
 675         if (b != 0) L->top = ra+b-1;
 676         if (L->openupval) luaF_close(L, base);
 677         L->savedpc = pc;
 678         b = luaD_poscall(L, ra);
 679         if (--nexeccalls == 0)  /* was previous function running `here'? */
 680           return;  /* no: return */
 681         else {  /* yes: continue its execution */
 682           if (b) L->top = L->ci->top;
 683           lua_assert(isLua(L->ci));
 684           lua_assert(GET_OPCODE(*((L->ci)->savedpc - 1)) == OP_CALL);
 685           goto reentry;
 686         }
 687       }
 688       case OP_FORLOOP: {
 689         lua_Number step = nvalue(ra+2);
 690         lua_Number idx = luai_numadd(nvalue(ra), step); /* increment index */
 691         lua_Number limit = nvalue(ra+1);
 692         if (luai_numlt(0, step) ? luai_numle(idx, limit)
 693                                 : luai_numle(limit, idx)) {
 694           dojump(L, pc, GETARG_sBx(i));  /* jump back */
 695           setnvalue(ra, idx);  /* update internal index... */
 696           setnvalue(ra+3, idx);  /* ...and external index */
 697         }
 698         continue;
 699       }
 700       case OP_FORPREP: {
 701         const TValue *init = ra;
 702         const TValue *plimit = ra+1;
 703         const TValue *pstep = ra+2;
 704         L->savedpc = pc;  /* next steps may throw errors */
 705         if (!tonumber(init, ra))
 706           luaG_runerror(L, LUA_QL("for") " initial value must be a number");
 707         else if (!tonumber(plimit, ra+1))
 708           luaG_runerror(L, LUA_QL("for") " limit must be a number");
 709         else if (!tonumber(pstep, ra+2))
 710           luaG_runerror(L, LUA_QL("for") " step must be a number");
 711         setnvalue(ra, luai_numsub(nvalue(ra), nvalue(pstep)));
 712         dojump(L, pc, GETARG_sBx(i));
 713         continue;
 714       }
 715       case OP_TFORLOOP: {
 716         StkId cb = ra + 3;  /* call base */
 717         setobjs2s(L, cb+2, ra+2);
 718         setobjs2s(L, cb+1, ra+1);
 719         setobjs2s(L, cb, ra);
 720         L->top = cb+3;  /* func. + 2 args (state and index) */
 721         Protect(luaD_call(L, cb, GETARG_C(i)));
 722         L->top = L->ci->top;
 723         cb = RA(i) + 3;  /* previous call may change the stack */
 724         if (!ttisnil(cb)) {  /* continue loop? */
 725           setobjs2s(L, cb-1, cb);  /* save control variable */
 726           dojump(L, pc, GETARG_sBx(*pc));  /* jump back */
 727         }
 728         pc++;
 729         continue;
 730       }
 731       case OP_SETLIST: {
 732         int n = GETARG_B(i);
 733         int c = GETARG_C(i);
 734         int last;
 735         Table *h;
 736         if (n == 0) {
 737           n = cast_int(L->top - ra) - 1;
 738           L->top = L->ci->top;
 739         }
 740         if (c == 0) c = cast_int(*pc++);
 741         runtime_check(L, ttistable(ra));
 742         h = hvalue(ra);
 743         last = ((c-1)*LFIELDS_PER_FLUSH) + n;
 744         if (last > h->sizearray)  /* needs more space? */
 745           luaH_resizearray(L, h, last);  /* pre-alloc it at once */
 746         for (; n > 0; n--) {
 747           TValue *val = ra+n;
 748           setobj2t(L, luaH_setnum(L, h, last--), val);
 749           luaC_barriert(L, h, val);
 750         }
 751         continue;
 752       }
 753       case OP_CLOSE: {
 754         luaF_close(L, ra);
 755         continue;
 756       }
 757       case OP_CLOSURE: {
 758         Proto *p;
 759         Closure *ncl;
 760         int nup, j;
 761         p = cl->p->p[GETARG_Bx(i)];
 762         nup = p->nups;
 763         ncl = luaF_newLclosure(L, nup, cl->env);
 764         ncl->l.p = p;
 765         for (j=0; j<nup; j++, pc++) {
 766           if (GET_OPCODE(*pc) == OP_GETUPVAL)
 767             ncl->l.upvals[j] = cl->upvals[GETARG_B(*pc)];
 768           else {
 769             lua_assert(GET_OPCODE(*pc) == OP_MOVE);
 770             ncl->l.upvals[j] = luaF_findupval(L, base + GETARG_B(*pc));
 771           }
 772         }
 773         setclvalue(L, ra, ncl);
 774         Protect(luaC_checkGC(L));
 775         continue;
 776       }
 777       case OP_VARARG: {
 778         int b = GETARG_B(i) - 1;
 779         int j;
 780         CallInfo *ci = L->ci;
 781         int n = cast_int(ci->base - ci->func) - cl->p->numparams - 1;
 782         if (b == LUA_MULTRET) {
 783           Protect(luaD_checkstack(L, n));
 784           ra = RA(i);  /* previous call may change the stack */
 785           b = n;
 786           L->top = ra + n;
 787         }
 788         for (j = 0; j < b; j++) {
 789           if (j < n) {
 790             setobjs2s(L, ra + j, ci->base - n + j);
 791           }
 792           else {
 793             setnilvalue(ra + j);
 794           }
 795         }
 796         continue;
 797       }
 798     }
 799   }
 800 }
 801