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Root/lua/lvm.cc

1/*
2** $Id: lvm.c,v 2.63 2006/06/05 15:58:59 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 MAXTAGLOOP100
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_MASKLINE) { /* instruction-hook set? */
65 if (L->hookcount == 0) {
66 resethookcount(L);
67 luaD_callhook(L, LUA_HOOKCOUNT, -1);
68 }
69 }
70 if (mask & LUA_MASKLINE) {
71 Proto *p = ci_func(L->ci)->l.p;
72 int npc = pcRel(pc, p);
73 int newline = getline(p, npc);
74 /* call linehook when enter a new function, when jump back (loop),
75 or when enter a new line */
76 if (npc == 0 || pc <= oldpc || newline != getline(p, pcRel(oldpc, p)))
77 luaD_callhook(L, LUA_HOOKLINE, newline);
78 }
79}
80
81
82static void callTMres (lua_State *L, StkId res, const TValue *f,
83 const TValue *p1, const TValue *p2) {
84 ptrdiff_t result = savestack(L, res);
85 setobj2s(L, L->top, f); /* push function */
86 setobj2s(L, L->top+1, p1); /* 1st argument */
87 setobj2s(L, L->top+2, p2); /* 2nd argument */
88 luaD_checkstack(L, 3);
89 L->top += 3;
90 luaD_call(L, L->top - 3, 1);
91 res = restorestack(L, result);
92 L->top--;
93 setobjs2s(L, res, L->top);
94}
95
96
97
98static void callTM (lua_State *L, const TValue *f, const TValue *p1,
99 const TValue *p2, const TValue *p3) {
100 setobj2s(L, L->top, f); /* push function */
101 setobj2s(L, L->top+1, p1); /* 1st argument */
102 setobj2s(L, L->top+2, p2); /* 2nd argument */
103 setobj2s(L, L->top+3, p3); /* 3th argument */
104 luaD_checkstack(L, 4);
105 L->top += 4;
106 luaD_call(L, L->top - 4, 0);
107}
108
109
110void luaV_gettable (lua_State *L, const TValue *t, TValue *key, StkId val) {
111 int loop;
112 for (loop = 0; loop < MAXTAGLOOP; loop++) {
113 const TValue *tm;
114 if (ttistable(t)) { /* `t' is a table? */
115 Table *h = hvalue(t);
116 const TValue *res = luaH_get(h, key); /* do a primitive get */
117 if (!ttisnil(res) || /* result is no nil? */
118 (tm = fasttm(L, h->metatable, TM_INDEX)) == NULL) { /* or no TM? */
119 setobj2s(L, val, res);
120 return;
121 }
122 /* else will try the tag method */
123 }
124 else if (ttisnil(tm = luaT_gettmbyobj(L, t, TM_INDEX)))
125 luaG_typeerror(L, t, "index");
126 if (ttisfunction(tm)) {
127 callTMres(L, val, tm, t, key);
128 return;
129 }
130 t = tm; /* else repeat with `tm' */
131 }
132 luaG_runerror(L, "loop in gettable");
133}
134
135
136void luaV_settable (lua_State *L, const TValue *t, TValue *key, StkId val) {
137 int loop;
138 for (loop = 0; loop < MAXTAGLOOP; loop++) {
139 const TValue *tm;
140 if (ttistable(t)) { /* `t' is a table? */
141 Table *h = hvalue(t);
142 TValue *oldval = luaH_set(L, h, key); /* do a primitive set */
143 if (!ttisnil(oldval) || /* result is no nil? */
144 (tm = fasttm(L, h->metatable, TM_NEWINDEX)) == NULL) { /* or no TM? */
145 setobj2t(L, oldval, val);
146 luaC_barriert(L, h, val);
147 return;
148 }
149 /* else will try the tag method */
150 }
151 else if (ttisnil(tm = luaT_gettmbyobj(L, t, TM_NEWINDEX)))
152 luaG_typeerror(L, t, "index");
153 if (ttisfunction(tm)) {
154 callTM(L, tm, t, key, val);
155 return;
156 }
157 t = tm; /* else repeat with `tm' */
158 }
159 luaG_runerror(L, "loop in settable");
160}
161
162
163static int call_binTM (lua_State *L, const TValue *p1, const TValue *p2,
164 StkId res, TMS event) {
165 const TValue *tm = luaT_gettmbyobj(L, p1, event); /* try first operand */
166 if (ttisnil(tm))
167 tm = luaT_gettmbyobj(L, p2, event); /* try second operand */
168 if (!ttisfunction(tm)) return 0;
169 callTMres(L, res, tm, p1, p2);
170 return 1;
171}
172
173
174static const TValue *get_compTM (lua_State *L, Table *mt1, Table *mt2,
175 TMS event) {
176 const TValue *tm1 = fasttm(L, mt1, event);
177 const TValue *tm2;
178 if (tm1 == NULL) return NULL; /* no metamethod */
179 if (mt1 == mt2) return tm1; /* same metatables => same metamethods */
180 tm2 = fasttm(L, mt2, event);
181 if (tm2 == NULL) return NULL; /* no metamethod */
182 if (luaO_rawequalObj(tm1, tm2)) /* same metamethods? */
183 return tm1;
184 return NULL;
185}
186
187
188static int call_orderTM (lua_State *L, const TValue *p1, const TValue *p2,
189 TMS event) {
190 const TValue *tm1 = luaT_gettmbyobj(L, p1, event);
191 const TValue *tm2;
192 if (ttisnil(tm1)) return -1; /* no metamethod? */
193 tm2 = luaT_gettmbyobj(L, p2, event);
194 if (!luaO_rawequalObj(tm1, tm2)) /* different metamethods? */
195 return -1;
196 callTMres(L, L->top, tm1, p1, p2);
197 return !l_isfalse(L->top);
198}
199
200
201static int l_strcmp (const TString *ls, const TString *rs) {
202 const char *l = getstr(ls);
203 size_t ll = ls->tsv.len;
204 const char *r = getstr(rs);
205 size_t lr = rs->tsv.len;
206 for (;;) {
207 int temp = strcoll(l, r);
208 if (temp != 0) return temp;
209 else { /* strings are equal up to a `\0' */
210 size_t len = strlen(l); /* index of first `\0' in both strings */
211 if (len == lr) /* r is finished? */
212 return (len == ll) ? 0 : 1;
213 else if (len == ll) /* l is finished? */
214 return -1; /* l is smaller than r (because r is not finished) */
215 /* both strings longer than `len'; go on comparing (after the `\0') */
216 len++;
217 l += len; ll -= len; r += len; lr -= len;
218 }
219 }
220}
221
222
223int luaV_lessthan (lua_State *L, const TValue *l, const TValue *r) {
224 int res;
225 if (ttype(l) != ttype(r))
226 return luaG_ordererror(L, l, r);
227 else if (ttisnumber(l))
228 return luai_numlt(nvalue(l), nvalue(r));
229 else if (ttisstring(l))
230 return l_strcmp(rawtsvalue(l), rawtsvalue(r)) < 0;
231 else if ((res = call_orderTM(L, l, r, TM_LT)) != -1)
232 return res;
233 return luaG_ordererror(L, l, r);
234}
235
236
237static int lessequal (lua_State *L, const TValue *l, const TValue *r) {
238 int res;
239 if (ttype(l) != ttype(r))
240 return luaG_ordererror(L, l, r);
241 else if (ttisnumber(l))
242 return luai_numle(nvalue(l), nvalue(r));
243 else if (ttisstring(l))
244 return l_strcmp(rawtsvalue(l), rawtsvalue(r)) <= 0;
245 else if ((res = call_orderTM(L, l, r, TM_LE)) != -1) /* first try `le' */
246 return res;
247 else if ((res = call_orderTM(L, r, l, TM_LT)) != -1) /* else try `lt' */
248 return !res;
249 return luaG_ordererror(L, l, r);
250}
251
252
253int luaV_equalval (lua_State *L, const TValue *t1, const TValue *t2) {
254 const TValue *tm;
255 lua_assert(ttype(t1) == ttype(t2));
256 switch (ttype(t1)) {
257 case LUA_TNIL: return 1;
258 case LUA_TNUMBER: return luai_numeq(nvalue(t1), nvalue(t2));
259 case LUA_TBOOLEAN: return bvalue(t1) == bvalue(t2); /* true must be 1 !! */
260 case LUA_TLIGHTUSERDATA: return pvalue(t1) == pvalue(t2);
261 case LUA_TUSERDATA: {
262 if (uvalue(t1) == uvalue(t2)) return 1;
263 tm = get_compTM(L, uvalue(t1)->metatable, uvalue(t2)->metatable,
264 TM_EQ);
265 break; /* will try TM */
266 }
267 case LUA_TTABLE: {
268 if (hvalue(t1) == hvalue(t2)) return 1;
269 tm = get_compTM(L, hvalue(t1)->metatable, hvalue(t2)->metatable, TM_EQ);
270 break; /* will try TM */
271 }
272 default: return gcvalue(t1) == gcvalue(t2);
273 }
274 if (tm == NULL) return 0; /* no TM? */
275 callTMres(L, L->top, tm, t1, t2); /* call TM */
276 return !l_isfalse(L->top);
277}
278
279
280void luaV_concat (lua_State *L, int total, int last) {
281 do {
282 StkId top = L->base + last + 1;
283 int n = 2; /* number of elements handled in this pass (at least 2) */
284 if (!tostring(L, top-2) || !tostring(L, top-1)) {
285 if (!call_binTM(L, top-2, top-1, top-2, TM_CONCAT))
286 luaG_concaterror(L, top-2, top-1);
287 } else if (tsvalue(top-1)->len > 0) { /* if len=0, do nothing */
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, \
348ISK(GETARG_B(i)) ? k+INDEXK(GETARG_B(i)) : base+GETARG_B(i))
349#define RKC(i)check_exp(getCMode(GET_OPCODE(i)) == OpArgK, \
350ISK(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

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