1/*
2** $Id: lvm.c,v 2.268.1.1 2017/04/19 17:39:34 roberto Exp $
3** Lua virtual machine
4** See Copyright Notice in lua.h
5*/
6
7#define lvm_c
8#define LUA_CORE
9
10#include "lprefix.h"
11
12#include <float.h>
13#include <limits.h>
14#include <math.h>
15#include <stdio.h>
16#include <stdlib.h>
17#include <string.h>
18
19#include "lua.h"
20
21#include "ldebug.h"
22#include "ldo.h"
23#include "lfunc.h"
24#include "lgc.h"
25#include "lobject.h"
26#include "lopcodes.h"
27#include "lstate.h"
28#include "lstring.h"
29#include "ltable.h"
30#include "ltm.h"
31#include "lvm.h"
32
33
34/* limit for table tag-method chains (to avoid loops) */
35#define MAXTAGLOOP 2000
36
37
38
39/*
40** 'l_intfitsf' checks whether a given integer can be converted to a
41** float without rounding. Used in comparisons. Left undefined if
42** all integers fit in a float precisely.
43*/
44#if !defined(l_intfitsf)
45
46/* number of bits in the mantissa of a float */
47#define NBM (l_mathlim(MANT_DIG))
48
49/*
50** Check whether some integers may not fit in a float, that is, whether
51** (maxinteger >> NBM) > 0 (that implies (1 << NBM) <= maxinteger).
52** (The shifts are done in parts to avoid shifting by more than the size
53** of an integer. In a worst case, NBM == 113 for long double and
54** sizeof(integer) == 32.)
55*/
56#if ((((LUA_MAXINTEGER >> (NBM / 4)) >> (NBM / 4)) >> (NBM / 4)) \
57 >> (NBM - (3 * (NBM / 4)))) > 0
58
59#define l_intfitsf(i) \
60 (-((lua_Integer)1 << NBM) <= (i) && (i) <= ((lua_Integer)1 << NBM))
61
62#endif
63
64#endif
65
66
67
68/*
69** Try to convert a value to a float. The float case is already handled
70** by the macro 'tonumber'.
71*/
72int luaV_tonumber_ (const TValue *obj, lua_Number *n) {
73 TValue v;
74 if (ttisinteger(obj)) {
75 *n = cast_num(ivalue(obj));
76 return 1;
77 }
78 else if (cvt2num(obj) && /* string convertible to number? */
79 luaO_str2num(svalue(obj), &v) == vslen(obj) + 1) {
80 *n = nvalue(&v); /* convert result of 'luaO_str2num' to a float */
81 return 1;
82 }
83 else
84 return 0; /* conversion failed */
85}
86
87
88/*
89** try to convert a value to an integer, rounding according to 'mode':
90** mode == 0: accepts only integral values
91** mode == 1: takes the floor of the number
92** mode == 2: takes the ceil of the number
93*/
94int luaV_tointeger (const TValue *obj, lua_Integer *p, int mode) {
95 TValue v;
96 again:
97 if (ttisfloat(obj)) {
98 lua_Number n = fltvalue(obj);
99 lua_Number f = l_floor(n);
100 if (n != f) { /* not an integral value? */
101 if (mode == 0) return 0; /* fails if mode demands integral value */
102 else if (mode > 1) /* needs ceil? */
103 f += 1; /* convert floor to ceil (remember: n != f) */
104 }
105 return lua_numbertointeger(f, p);
106 }
107 else if (ttisinteger(obj)) {
108 *p = ivalue(obj);
109 return 1;
110 }
111 else if (cvt2num(obj) &&
112 luaO_str2num(svalue(obj), &v) == vslen(obj) + 1) {
113 obj = &v;
114 goto again; /* convert result from 'luaO_str2num' to an integer */
115 }
116 return 0; /* conversion failed */
117}
118
119
120/*
121** Try to convert a 'for' limit to an integer, preserving the
122** semantics of the loop.
123** (The following explanation assumes a non-negative step; it is valid
124** for negative steps mutatis mutandis.)
125** If the limit can be converted to an integer, rounding down, that is
126** it.
127** Otherwise, check whether the limit can be converted to a number. If
128** the number is too large, it is OK to set the limit as LUA_MAXINTEGER,
129** which means no limit. If the number is too negative, the loop
130** should not run, because any initial integer value is larger than the
131** limit. So, it sets the limit to LUA_MININTEGER. 'stopnow' corrects
132** the extreme case when the initial value is LUA_MININTEGER, in which
133** case the LUA_MININTEGER limit would still run the loop once.
134*/
135static int forlimit (const TValue *obj, lua_Integer *p, lua_Integer step,
136 int *stopnow) {
137 *stopnow = 0; /* usually, let loops run */
138 if (!luaV_tointeger(obj, p, (step < 0 ? 2 : 1))) { /* not fit in integer? */
139 lua_Number n; /* try to convert to float */
140 if (!tonumber(obj, &n)) /* cannot convert to float? */
141 return 0; /* not a number */
142 if (luai_numlt(0, n)) { /* if true, float is larger than max integer */
143 *p = LUA_MAXINTEGER;
144 if (step < 0) *stopnow = 1;
145 }
146 else { /* float is smaller than min integer */
147 *p = LUA_MININTEGER;
148 if (step >= 0) *stopnow = 1;
149 }
150 }
151 return 1;
152}
153
154
155/*
156** Finish the table access 'val = t[key]'.
157** if 'slot' is NULL, 't' is not a table; otherwise, 'slot' points to
158** t[k] entry (which must be nil).
159*/
160void luaV_finishget (lua_State *L, const TValue *t, TValue *key, StkId val,
161 const TValue *slot) {
162 int loop; /* counter to avoid infinite loops */
163 const TValue *tm; /* metamethod */
164 for (loop = 0; loop < MAXTAGLOOP; loop++) {
165 if (slot == NULL) { /* 't' is not a table? */
166 lua_assert(!ttistable(t));
167 tm = luaT_gettmbyobj(L, t, TM_INDEX);
168 if (ttisnil(tm))
169 luaG_typeerror(L, t, "index"); /* no metamethod */
170 /* else will try the metamethod */
171 }
172 else { /* 't' is a table */
173 lua_assert(ttisnil(slot));
174 tm = fasttm(L, hvalue(t)->metatable, TM_INDEX); /* table's metamethod */
175 if (tm == NULL) { /* no metamethod? */
176 setnilvalue(val); /* result is nil */
177 return;
178 }
179 /* else will try the metamethod */
180 }
181 if (ttisfunction(tm)) { /* is metamethod a function? */
182 luaT_callTM(L, tm, t, key, val, 1); /* call it */
183 return;
184 }
185 t = tm; /* else try to access 'tm[key]' */
186 if (luaV_fastget(L,t,key,slot,luaH_get)) { /* fast track? */
187 setobj2s(L, val, slot); /* done */
188 return;
189 }
190 /* else repeat (tail call 'luaV_finishget') */
191 }
192 luaG_runerror(L, "'__index' chain too long; possible loop");
193}
194
195
196/*
197** Finish a table assignment 't[key] = val'.
198** If 'slot' is NULL, 't' is not a table. Otherwise, 'slot' points
199** to the entry 't[key]', or to 'luaO_nilobject' if there is no such
200** entry. (The value at 'slot' must be nil, otherwise 'luaV_fastset'
201** would have done the job.)
202*/
203void luaV_finishset (lua_State *L, const TValue *t, TValue *key,
204 StkId val, const TValue *slot) {
205 int loop; /* counter to avoid infinite loops */
206 for (loop = 0; loop < MAXTAGLOOP; loop++) {
207 const TValue *tm; /* '__newindex' metamethod */
208 if (slot != NULL) { /* is 't' a table? */
209 Table *h = hvalue(t); /* save 't' table */
210 lua_assert(ttisnil(slot)); /* old value must be nil */
211 tm = fasttm(L, h->metatable, TM_NEWINDEX); /* get metamethod */
212 if (tm == NULL) { /* no metamethod? */
213 if (slot == luaO_nilobject) /* no previous entry? */
214 slot = luaH_newkey(L, h, key); /* create one */
215 /* no metamethod and (now) there is an entry with given key */
216 setobj2t(L, cast(TValue *, slot), val); /* set its new value */
217 invalidateTMcache(h);
218 luaC_barrierback(L, h, val);
219 return;
220 }
221 /* else will try the metamethod */
222 }
223 else { /* not a table; check metamethod */
224 if (ttisnil(tm = luaT_gettmbyobj(L, t, TM_NEWINDEX)))
225 luaG_typeerror(L, t, "index");
226 }
227 /* try the metamethod */
228 if (ttisfunction(tm)) {
229 luaT_callTM(L, tm, t, key, val, 0);
230 return;
231 }
232 t = tm; /* else repeat assignment over 'tm' */
233 if (luaV_fastset(L, t, key, slot, luaH_get, val))
234 return; /* done */
235 /* else loop */
236 }
237 luaG_runerror(L, "'__newindex' chain too long; possible loop");
238}
239
240
241/*
242** Compare two strings 'ls' x 'rs', returning an integer smaller-equal-
243** -larger than zero if 'ls' is smaller-equal-larger than 'rs'.
244** The code is a little tricky because it allows '\0' in the strings
245** and it uses 'strcoll' (to respect locales) for each segments
246** of the strings.
247*/
248static int l_strcmp (const TString *ls, const TString *rs) {
249 const char *l = getstr(ls);
250 size_t ll = tsslen(ls);
251 const char *r = getstr(rs);
252 size_t lr = tsslen(rs);
253 for (;;) { /* for each segment */
254 int temp = strcoll(l, r);
255 if (temp != 0) /* not equal? */
256 return temp; /* done */
257 else { /* strings are equal up to a '\0' */
258 size_t len = strlen(l); /* index of first '\0' in both strings */
259 if (len == lr) /* 'rs' is finished? */
260 return (len == ll) ? 0 : 1; /* check 'ls' */
261 else if (len == ll) /* 'ls' is finished? */
262 return -1; /* 'ls' is smaller than 'rs' ('rs' is not finished) */
263 /* both strings longer than 'len'; go on comparing after the '\0' */
264 len++;
265 l += len; ll -= len; r += len; lr -= len;
266 }
267 }
268}
269
270
271/*
272** Check whether integer 'i' is less than float 'f'. If 'i' has an
273** exact representation as a float ('l_intfitsf'), compare numbers as
274** floats. Otherwise, if 'f' is outside the range for integers, result
275** is trivial. Otherwise, compare them as integers. (When 'i' has no
276** float representation, either 'f' is "far away" from 'i' or 'f' has
277** no precision left for a fractional part; either way, how 'f' is
278** truncated is irrelevant.) When 'f' is NaN, comparisons must result
279** in false.
280*/
281static int LTintfloat (lua_Integer i, lua_Number f) {
282#if defined(l_intfitsf)
283 if (!l_intfitsf(i)) {
284 if (f >= -cast_num(LUA_MININTEGER)) /* -minint == maxint + 1 */
285 return 1; /* f >= maxint + 1 > i */
286 else if (f > cast_num(LUA_MININTEGER)) /* minint < f <= maxint ? */
287 return (i < cast(lua_Integer, f)); /* compare them as integers */
288 else /* f <= minint <= i (or 'f' is NaN) --> not(i < f) */
289 return 0;
290 }
291#endif
292 return luai_numlt(cast_num(i), f); /* compare them as floats */
293}
294
295
296/*
297** Check whether integer 'i' is less than or equal to float 'f'.
298** See comments on previous function.
299*/
300static int LEintfloat (lua_Integer i, lua_Number f) {
301#if defined(l_intfitsf)
302 if (!l_intfitsf(i)) {
303 if (f >= -cast_num(LUA_MININTEGER)) /* -minint == maxint + 1 */
304 return 1; /* f >= maxint + 1 > i */
305 else if (f >= cast_num(LUA_MININTEGER)) /* minint <= f <= maxint ? */
306 return (i <= cast(lua_Integer, f)); /* compare them as integers */
307 else /* f < minint <= i (or 'f' is NaN) --> not(i <= f) */
308 return 0;
309 }
310#endif
311 return luai_numle(cast_num(i), f); /* compare them as floats */
312}
313
314
315/*
316** Return 'l < r', for numbers.
317*/
318static int LTnum (const TValue *l, const TValue *r) {
319 if (ttisinteger(l)) {
320 lua_Integer li = ivalue(l);
321 if (ttisinteger(r))
322 return li < ivalue(r); /* both are integers */
323 else /* 'l' is int and 'r' is float */
324 return LTintfloat(li, fltvalue(r)); /* l < r ? */
325 }
326 else {
327 lua_Number lf = fltvalue(l); /* 'l' must be float */
328 if (ttisfloat(r))
329 return luai_numlt(lf, fltvalue(r)); /* both are float */
330 else if (luai_numisnan(lf)) /* 'r' is int and 'l' is float */
331 return 0; /* NaN < i is always false */
332 else /* without NaN, (l < r) <--> not(r <= l) */
333 return !LEintfloat(ivalue(r), lf); /* not (r <= l) ? */
334 }
335}
336
337
338/*
339** Return 'l <= r', for numbers.
340*/
341static int LEnum (const TValue *l, const TValue *r) {
342 if (ttisinteger(l)) {
343 lua_Integer li = ivalue(l);
344 if (ttisinteger(r))
345 return li <= ivalue(r); /* both are integers */
346 else /* 'l' is int and 'r' is float */
347 return LEintfloat(li, fltvalue(r)); /* l <= r ? */
348 }
349 else {
350 lua_Number lf = fltvalue(l); /* 'l' must be float */
351 if (ttisfloat(r))
352 return luai_numle(lf, fltvalue(r)); /* both are float */
353 else if (luai_numisnan(lf)) /* 'r' is int and 'l' is float */
354 return 0; /* NaN <= i is always false */
355 else /* without NaN, (l <= r) <--> not(r < l) */
356 return !LTintfloat(ivalue(r), lf); /* not (r < l) ? */
357 }
358}
359
360
361/*
362** Main operation less than; return 'l < r'.
363*/
364int luaV_lessthan (lua_State *L, const TValue *l, const TValue *r) {
365 int res;
366 if (ttisnumber(l) && ttisnumber(r)) /* both operands are numbers? */
367 return LTnum(l, r);
368 else if (ttisstring(l) && ttisstring(r)) /* both are strings? */
369 return l_strcmp(tsvalue(l), tsvalue(r)) < 0;
370 else if ((res = luaT_callorderTM(L, l, r, TM_LT)) < 0) /* no metamethod? */
371 luaG_ordererror(L, l, r); /* error */
372 return res;
373}
374
375
376/*
377** Main operation less than or equal to; return 'l <= r'. If it needs
378** a metamethod and there is no '__le', try '__lt', based on
379** l <= r iff !(r < l) (assuming a total order). If the metamethod
380** yields during this substitution, the continuation has to know
381** about it (to negate the result of r<l); bit CIST_LEQ in the call
382** status keeps that information.
383*/
384int luaV_lessequal (lua_State *L, const TValue *l, const TValue *r) {
385 int res;
386 if (ttisnumber(l) && ttisnumber(r)) /* both operands are numbers? */
387 return LEnum(l, r);
388 else if (ttisstring(l) && ttisstring(r)) /* both are strings? */
389 return l_strcmp(tsvalue(l), tsvalue(r)) <= 0;
390 else if ((res = luaT_callorderTM(L, l, r, TM_LE)) >= 0) /* try 'le' */
391 return res;
392 else { /* try 'lt': */
393 L->ci->callstatus |= CIST_LEQ; /* mark it is doing 'lt' for 'le' */
394 res = luaT_callorderTM(L, r, l, TM_LT);
395 L->ci->callstatus ^= CIST_LEQ; /* clear mark */
396 if (res < 0)
397 luaG_ordererror(L, l, r);
398 return !res; /* result is negated */
399 }
400}
401
402
403/*
404** Main operation for equality of Lua values; return 't1 == t2'.
405** L == NULL means raw equality (no metamethods)
406*/
407int luaV_equalobj (lua_State *L, const TValue *t1, const TValue *t2) {
408 const TValue *tm;
409 if (ttype(t1) != ttype(t2)) { /* not the same variant? */
410 if (ttnov(t1) != ttnov(t2) || ttnov(t1) != LUA_TNUMBER)
411 return 0; /* only numbers can be equal with different variants */
412 else { /* two numbers with different variants */
413 lua_Integer i1, i2; /* compare them as integers */
414 return (tointeger(t1, &i1) && tointeger(t2, &i2) && i1 == i2);
415 }
416 }
417 /* values have same type and same variant */
418 switch (ttype(t1)) {
419 case LUA_TNIL: return 1;
420 case LUA_TNUMINT: return (ivalue(t1) == ivalue(t2));
421 case LUA_TNUMFLT: return luai_numeq(fltvalue(t1), fltvalue(t2));
422 case LUA_TBOOLEAN: return bvalue(t1) == bvalue(t2); /* true must be 1 !! */
423 case LUA_TLIGHTUSERDATA: return pvalue(t1) == pvalue(t2);
424 case LUA_TLCF: return fvalue(t1) == fvalue(t2);
425 case LUA_TSHRSTR: return eqshrstr(tsvalue(t1), tsvalue(t2));
426 case LUA_TLNGSTR: return luaS_eqlngstr(tsvalue(t1), tsvalue(t2));
427 case LUA_TUSERDATA: {
428 if (uvalue(t1) == uvalue(t2)) return 1;
429 else if (L == NULL) return 0;
430 tm = fasttm(L, uvalue(t1)->metatable, TM_EQ);
431 if (tm == NULL)
432 tm = fasttm(L, uvalue(t2)->metatable, TM_EQ);
433 break; /* will try TM */
434 }
435 case LUA_TTABLE: {
436 if (hvalue(t1) == hvalue(t2)) return 1;
437 else if (L == NULL) return 0;
438 tm = fasttm(L, hvalue(t1)->metatable, TM_EQ);
439 if (tm == NULL)
440 tm = fasttm(L, hvalue(t2)->metatable, TM_EQ);
441 break; /* will try TM */
442 }
443 default:
444 return gcvalue(t1) == gcvalue(t2);
445 }
446 if (tm == NULL) /* no TM? */
447 return 0; /* objects are different */
448 luaT_callTM(L, tm, t1, t2, L->top, 1); /* call TM */
449 return !l_isfalse(L->top);
450}
451
452
453/* macro used by 'luaV_concat' to ensure that element at 'o' is a string */
454#define tostring(L,o) \
455 (ttisstring(o) || (cvt2str(o) && (luaO_tostring(L, o), 1)))
456
457#define isemptystr(o) (ttisshrstring(o) && tsvalue(o)->shrlen == 0)
458
459/* copy strings in stack from top - n up to top - 1 to buffer */
460static void copy2buff (StkId top, int n, char *buff) {
461 size_t tl = 0; /* size already copied */
462 do {
463 size_t l = vslen(top - n); /* length of string being copied */
464 memcpy(buff + tl, svalue(top - n), l * sizeof(char));
465 tl += l;
466 } while (--n > 0);
467}
468
469
470/*
471** Main operation for concatenation: concat 'total' values in the stack,
472** from 'L->top - total' up to 'L->top - 1'.
473*/
474void luaV_concat (lua_State *L, int total) {
475 lua_assert(total >= 2);
476 do {
477 StkId top = L->top;
478 int n = 2; /* number of elements handled in this pass (at least 2) */
479 if (!(ttisstring(top-2) || cvt2str(top-2)) || !tostring(L, top-1))
480 luaT_trybinTM(L, top-2, top-1, top-2, TM_CONCAT);
481 else if (isemptystr(top - 1)) /* second operand is empty? */
482 cast_void(tostring(L, top - 2)); /* result is first operand */
483 else if (isemptystr(top - 2)) { /* first operand is an empty string? */
484 setobjs2s(L, top - 2, top - 1); /* result is second op. */
485 }
486 else {
487 /* at least two non-empty string values; get as many as possible */
488 size_t tl = vslen(top - 1);
489 TString *ts;
490 /* collect total length and number of strings */
491 for (n = 1; n < total && tostring(L, top - n - 1); n++) {
492 size_t l = vslen(top - n - 1);
493 if (l >= (MAX_SIZE/sizeof(char)) - tl)
494 luaG_runerror(L, "string length overflow");
495 tl += l;
496 }
497 if (tl <= LUAI_MAXSHORTLEN) { /* is result a short string? */
498 char buff[LUAI_MAXSHORTLEN];
499 copy2buff(top, n, buff); /* copy strings to buffer */
500 ts = luaS_newlstr(L, buff, tl);
501 }
502 else { /* long string; copy strings directly to final result */
503 ts = luaS_createlngstrobj(L, tl);
504 copy2buff(top, n, getstr(ts));
505 }
506 setsvalue2s(L, top - n, ts); /* create result */
507 }
508 total -= n-1; /* got 'n' strings to create 1 new */
509 L->top -= n-1; /* popped 'n' strings and pushed one */
510 } while (total > 1); /* repeat until only 1 result left */
511}
512
513
514/*
515** Main operation 'ra' = #rb'.
516*/
517void luaV_objlen (lua_State *L, StkId ra, const TValue *rb) {
518 const TValue *tm;
519 switch (ttype(rb)) {
520 case LUA_TTABLE: {
521 Table *h = hvalue(rb);
522 tm = fasttm(L, h->metatable, TM_LEN);
523 if (tm) break; /* metamethod? break switch to call it */
524 setivalue(ra, luaH_getn(h)); /* else primitive len */
525 return;
526 }
527 case LUA_TSHRSTR: {
528 setivalue(ra, tsvalue(rb)->shrlen);
529 return;
530 }
531 case LUA_TLNGSTR: {
532 setivalue(ra, tsvalue(rb)->u.lnglen);
533 return;
534 }
535 default: { /* try metamethod */
536 tm = luaT_gettmbyobj(L, rb, TM_LEN);
537 if (ttisnil(tm)) /* no metamethod? */
538 luaG_typeerror(L, rb, "get length of");
539 break;
540 }
541 }
542 luaT_callTM(L, tm, rb, rb, ra, 1);
543}
544
545
546/*
547** Integer division; return 'm // n', that is, floor(m/n).
548** C division truncates its result (rounds towards zero).
549** 'floor(q) == trunc(q)' when 'q >= 0' or when 'q' is integer,
550** otherwise 'floor(q) == trunc(q) - 1'.
551*/
552lua_Integer luaV_div (lua_State *L, lua_Integer m, lua_Integer n) {
553 if (l_castS2U(n) + 1u <= 1u) { /* special cases: -1 or 0 */
554 if (n == 0)
555 luaG_runerror(L, "attempt to divide by zero");
556 return intop(-, 0, m); /* n==-1; avoid overflow with 0x80000...//-1 */
557 }
558 else {
559 lua_Integer q = m / n; /* perform C division */
560 if ((m ^ n) < 0 && m % n != 0) /* 'm/n' would be negative non-integer? */
561 q -= 1; /* correct result for different rounding */
562 return q;
563 }
564}
565
566
567/*
568** Integer modulus; return 'm % n'. (Assume that C '%' with
569** negative operands follows C99 behavior. See previous comment
570** about luaV_div.)
571*/
572lua_Integer luaV_mod (lua_State *L, lua_Integer m, lua_Integer n) {
573 if (l_castS2U(n) + 1u <= 1u) { /* special cases: -1 or 0 */
574 if (n == 0)
575 luaG_runerror(L, "attempt to perform 'n%%0'");
576 return 0; /* m % -1 == 0; avoid overflow with 0x80000...%-1 */
577 }
578 else {
579 lua_Integer r = m % n;
580 if (r != 0 && (m ^ n) < 0) /* 'm/n' would be non-integer negative? */
581 r += n; /* correct result for different rounding */
582 return r;
583 }
584}
585
586
587/* number of bits in an integer */
588#define NBITS cast_int(sizeof(lua_Integer) * CHAR_BIT)
589
590/*
591** Shift left operation. (Shift right just negates 'y'.)
592*/
593lua_Integer luaV_shiftl (lua_Integer x, lua_Integer y) {
594 if (y < 0) { /* shift right? */
595 if (y <= -NBITS) return 0;
596 else return intop(>>, x, -y);
597 }
598 else { /* shift left */
599 if (y >= NBITS) return 0;
600 else return intop(<<, x, y);
601 }
602}
603
604
605/*
606** check whether cached closure in prototype 'p' may be reused, that is,
607** whether there is a cached closure with the same upvalues needed by
608** new closure to be created.
609*/
610static LClosure *getcached (Proto *p, UpVal **encup, StkId base) {
611 LClosure *c = p->cache;
612 if (c != NULL) { /* is there a cached closure? */
613 int nup = p->sizeupvalues;
614 Upvaldesc *uv = p->upvalues;
615 int i;
616 for (i = 0; i < nup; i++) { /* check whether it has right upvalues */
617 TValue *v = uv[i].instack ? base + uv[i].idx : encup[uv[i].idx]->v;
618 if (c->upvals[i]->v != v)
619 return NULL; /* wrong upvalue; cannot reuse closure */
620 }
621 }
622 return c; /* return cached closure (or NULL if no cached closure) */
623}
624
625
626/*
627** create a new Lua closure, push it in the stack, and initialize
628** its upvalues. Note that the closure is not cached if prototype is
629** already black (which means that 'cache' was already cleared by the
630** GC).
631*/
632static void pushclosure (lua_State *L, Proto *p, UpVal **encup, StkId base,
633 StkId ra) {
634 int nup = p->sizeupvalues;
635 Upvaldesc *uv = p->upvalues;
636 int i;
637 LClosure *ncl = luaF_newLclosure(L, nup);
638 ncl->p = p;
639 setclLvalue(L, ra, ncl); /* anchor new closure in stack */
640 for (i = 0; i < nup; i++) { /* fill in its upvalues */
641 if (uv[i].instack) /* upvalue refers to local variable? */
642 ncl->upvals[i] = luaF_findupval(L, base + uv[i].idx);
643 else /* get upvalue from enclosing function */
644 ncl->upvals[i] = encup[uv[i].idx];
645 ncl->upvals[i]->refcount++;
646 /* new closure is white, so we do not need a barrier here */
647 }
648 if (!isblack(p)) /* cache will not break GC invariant? */
649 p->cache = ncl; /* save it on cache for reuse */
650}
651
652
653/*
654** finish execution of an opcode interrupted by an yield
655*/
656void luaV_finishOp (lua_State *L) {
657 CallInfo *ci = L->ci;
658 StkId base = ci->u.l.base;
659 Instruction inst = *(ci->u.l.savedpc - 1); /* interrupted instruction */
660 OpCode op = GET_OPCODE(inst);
661 switch (op) { /* finish its execution */
662 case OP_ADD: case OP_SUB: case OP_MUL: case OP_DIV: case OP_IDIV:
663 case OP_BAND: case OP_BOR: case OP_BXOR: case OP_SHL: case OP_SHR:
664 case OP_MOD: case OP_POW:
665 case OP_UNM: case OP_BNOT: case OP_LEN:
666 case OP_GETTABUP: case OP_GETTABLE: case OP_SELF: {
667 setobjs2s(L, base + GETARG_A(inst), --L->top);
668 break;
669 }
670 case OP_LE: case OP_LT: case OP_EQ: {
671 int res = !l_isfalse(L->top - 1);
672 L->top--;
673 if (ci->callstatus & CIST_LEQ) { /* "<=" using "<" instead? */
674 lua_assert(op == OP_LE);
675 ci->callstatus ^= CIST_LEQ; /* clear mark */
676 res = !res; /* negate result */
677 }
678 lua_assert(GET_OPCODE(*ci->u.l.savedpc) == OP_JMP);
679 if (res != GETARG_A(inst)) /* condition failed? */
680 ci->u.l.savedpc++; /* skip jump instruction */
681 break;
682 }
683 case OP_CONCAT: {
684 StkId top = L->top - 1; /* top when 'luaT_trybinTM' was called */
685 int b = GETARG_B(inst); /* first element to concatenate */
686 int total = cast_int(top - 1 - (base + b)); /* yet to concatenate */
687 setobj2s(L, top - 2, top); /* put TM result in proper position */
688 if (total > 1) { /* are there elements to concat? */
689 L->top = top - 1; /* top is one after last element (at top-2) */
690 luaV_concat(L, total); /* concat them (may yield again) */
691 }
692 /* move final result to final position */
693 setobj2s(L, ci->u.l.base + GETARG_A(inst), L->top - 1);
694 L->top = ci->top; /* restore top */
695 break;
696 }
697 case OP_TFORCALL: {
698 lua_assert(GET_OPCODE(*ci->u.l.savedpc) == OP_TFORLOOP);
699 L->top = ci->top; /* correct top */
700 break;
701 }
702 case OP_CALL: {
703 if (GETARG_C(inst) - 1 >= 0) /* nresults >= 0? */
704 L->top = ci->top; /* adjust results */
705 break;
706 }
707 case OP_TAILCALL: case OP_SETTABUP: case OP_SETTABLE:
708 break;
709 default: lua_assert(0);
710 }
711}
712
713
714
715
716/*
717** {==================================================================
718** Function 'luaV_execute': main interpreter loop
719** ===================================================================
720*/
721
722
723/*
724** some macros for common tasks in 'luaV_execute'
725*/
726
727
728#define RA(i) (base+GETARG_A(i))
729#define RB(i) check_exp(getBMode(GET_OPCODE(i)) == OpArgR, base+GETARG_B(i))
730#define RC(i) check_exp(getCMode(GET_OPCODE(i)) == OpArgR, base+GETARG_C(i))
731#define RKB(i) check_exp(getBMode(GET_OPCODE(i)) == OpArgK, \
732 ISK(GETARG_B(i)) ? k+INDEXK(GETARG_B(i)) : base+GETARG_B(i))
733#define RKC(i) check_exp(getCMode(GET_OPCODE(i)) == OpArgK, \
734 ISK(GETARG_C(i)) ? k+INDEXK(GETARG_C(i)) : base+GETARG_C(i))
735
736
737/* execute a jump instruction */
738#define dojump(ci,i,e) \
739 { int a = GETARG_A(i); \
740 if (a != 0) luaF_close(L, ci->u.l.base + a - 1); \
741 ci->u.l.savedpc += GETARG_sBx(i) + e; }
742
743/* for test instructions, execute the jump instruction that follows it */
744#define donextjump(ci) { i = *ci->u.l.savedpc; dojump(ci, i, 1); }
745
746
747#define Protect(x) { {x;}; base = ci->u.l.base; }
748
749#define checkGC(L,c) \
750 { luaC_condGC(L, L->top = (c), /* limit of live values */ \
751 Protect(L->top = ci->top)); /* restore top */ \
752 luai_threadyield(L); }
753
754
755/* fetch an instruction and prepare its execution */
756#define vmfetch() { \
757 i = *(ci->u.l.savedpc++); \
758 if (L->hookmask & (LUA_MASKLINE | LUA_MASKCOUNT)) \
759 Protect(luaG_traceexec(L)); \
760 ra = RA(i); /* WARNING: any stack reallocation invalidates 'ra' */ \
761 lua_assert(base == ci->u.l.base); \
762 lua_assert(base <= L->top && L->top < L->stack + L->stacksize); \
763}
764
765#define vmdispatch(o) switch(o)
766#define vmcase(l) case l:
767#define vmbreak break
768
769
770/*
771** copy of 'luaV_gettable', but protecting the call to potential
772** metamethod (which can reallocate the stack)
773*/
774#define gettableProtected(L,t,k,v) { const TValue *slot; \
775 if (luaV_fastget(L,t,k,slot,luaH_get)) { setobj2s(L, v, slot); } \
776 else Protect(luaV_finishget(L,t,k,v,slot)); }
777
778
779/* same for 'luaV_settable' */
780#define settableProtected(L,t,k,v) { const TValue *slot; \
781 if (!luaV_fastset(L,t,k,slot,luaH_get,v)) \
782 Protect(luaV_finishset(L,t,k,v,slot)); }
783
784
785
786void luaV_execute (lua_State *L) {
787 CallInfo *ci = L->ci;
788 LClosure *cl;
789 TValue *k;
790 StkId base;
791 ci->callstatus |= CIST_FRESH; /* fresh invocation of 'luaV_execute" */
792 newframe: /* reentry point when frame changes (call/return) */
793 lua_assert(ci == L->ci);
794 cl = clLvalue(ci->func); /* local reference to function's closure */
795 k = cl->p->k; /* local reference to function's constant table */
796 base = ci->u.l.base; /* local copy of function's base */
797 /* main loop of interpreter */
798 for (;;) {
799 Instruction i;
800 StkId ra;
801 vmfetch();
802 vmdispatch (GET_OPCODE(i)) {
803 vmcase(OP_MOVE) {
804 setobjs2s(L, ra, RB(i));
805 vmbreak;
806 }
807 vmcase(OP_LOADK) {
808 TValue *rb = k + GETARG_Bx(i);
809 setobj2s(L, ra, rb);
810 vmbreak;
811 }
812 vmcase(OP_LOADKX) {
813 TValue *rb;
814 lua_assert(GET_OPCODE(*ci->u.l.savedpc) == OP_EXTRAARG);
815 rb = k + GETARG_Ax(*ci->u.l.savedpc++);
816 setobj2s(L, ra, rb);
817 vmbreak;
818 }
819 vmcase(OP_LOADBOOL) {
820 setbvalue(ra, GETARG_B(i));
821 if (GETARG_C(i)) ci->u.l.savedpc++; /* skip next instruction (if C) */
822 vmbreak;
823 }
824 vmcase(OP_LOADNIL) {
825 int b = GETARG_B(i);
826 do {
827 setnilvalue(ra++);
828 } while (b--);
829 vmbreak;
830 }
831 vmcase(OP_GETUPVAL) {
832 int b = GETARG_B(i);
833 setobj2s(L, ra, cl->upvals[b]->v);
834 vmbreak;
835 }
836 vmcase(OP_GETTABUP) {
837 TValue *upval = cl->upvals[GETARG_B(i)]->v;
838 TValue *rc = RKC(i);
839 gettableProtected(L, upval, rc, ra);
840 vmbreak;
841 }
842 vmcase(OP_GETTABLE) {
843 StkId rb = RB(i);
844 TValue *rc = RKC(i);
845 gettableProtected(L, rb, rc, ra);
846 vmbreak;
847 }
848 vmcase(OP_SETTABUP) {
849 TValue *upval = cl->upvals[GETARG_A(i)]->v;
850 TValue *rb = RKB(i);
851 TValue *rc = RKC(i);
852 settableProtected(L, upval, rb, rc);
853 vmbreak;
854 }
855 vmcase(OP_SETUPVAL) {
856 UpVal *uv = cl->upvals[GETARG_B(i)];
857 setobj(L, uv->v, ra);
858 luaC_upvalbarrier(L, uv);
859 vmbreak;
860 }
861 vmcase(OP_SETTABLE) {
862 TValue *rb = RKB(i);
863 TValue *rc = RKC(i);
864 settableProtected(L, ra, rb, rc);
865 vmbreak;
866 }
867 vmcase(OP_NEWTABLE) {
868 int b = GETARG_B(i);
869 int c = GETARG_C(i);
870 Table *t = luaH_new(L);
871 sethvalue(L, ra, t);
872 if (b != 0 || c != 0)
873 luaH_resize(L, t, luaO_fb2int(b), luaO_fb2int(c));
874 checkGC(L, ra + 1);
875 vmbreak;
876 }
877 vmcase(OP_SELF) {
878 const TValue *aux;
879 StkId rb = RB(i);
880 TValue *rc = RKC(i);
881 TString *key = tsvalue(rc); /* key must be a string */
882 setobjs2s(L, ra + 1, rb);
883 if (luaV_fastget(L, rb, key, aux, luaH_getstr)) {
884 setobj2s(L, ra, aux);
885 }
886 else Protect(luaV_finishget(L, rb, rc, ra, aux));
887 vmbreak;
888 }
889 vmcase(OP_ADD) {
890 TValue *rb = RKB(i);
891 TValue *rc = RKC(i);
892 lua_Number nb; lua_Number nc;
893 if (ttisinteger(rb) && ttisinteger(rc)) {
894 lua_Integer ib = ivalue(rb); lua_Integer ic = ivalue(rc);
895 setivalue(ra, intop(+, ib, ic));
896 }
897 else if (tonumber(rb, &nb) && tonumber(rc, &nc)) {
898 setfltvalue(ra, luai_numadd(L, nb, nc));
899 }
900 else { Protect(luaT_trybinTM(L, rb, rc, ra, TM_ADD)); }
901 vmbreak;
902 }
903 vmcase(OP_SUB) {
904 TValue *rb = RKB(i);
905 TValue *rc = RKC(i);
906 lua_Number nb; lua_Number nc;
907 if (ttisinteger(rb) && ttisinteger(rc)) {
908 lua_Integer ib = ivalue(rb); lua_Integer ic = ivalue(rc);
909 setivalue(ra, intop(-, ib, ic));
910 }
911 else if (tonumber(rb, &nb) && tonumber(rc, &nc)) {
912 setfltvalue(ra, luai_numsub(L, nb, nc));
913 }
914 else { Protect(luaT_trybinTM(L, rb, rc, ra, TM_SUB)); }
915 vmbreak;
916 }
917 vmcase(OP_MUL) {
918 TValue *rb = RKB(i);
919 TValue *rc = RKC(i);
920 lua_Number nb; lua_Number nc;
921 if (ttisinteger(rb) && ttisinteger(rc)) {
922 lua_Integer ib = ivalue(rb); lua_Integer ic = ivalue(rc);
923 setivalue(ra, intop(*, ib, ic));
924 }
925 else if (tonumber(rb, &nb) && tonumber(rc, &nc)) {
926 setfltvalue(ra, luai_nummul(L, nb, nc));
927 }
928 else { Protect(luaT_trybinTM(L, rb, rc, ra, TM_MUL)); }
929 vmbreak;
930 }
931 vmcase(OP_DIV) { /* float division (always with floats) */
932 TValue *rb = RKB(i);
933 TValue *rc = RKC(i);
934 lua_Number nb; lua_Number nc;
935 if (tonumber(rb, &nb) && tonumber(rc, &nc)) {
936 setfltvalue(ra, luai_numdiv(L, nb, nc));
937 }
938 else { Protect(luaT_trybinTM(L, rb, rc, ra, TM_DIV)); }
939 vmbreak;
940 }
941 vmcase(OP_BAND) {
942 TValue *rb = RKB(i);
943 TValue *rc = RKC(i);
944 lua_Integer ib; lua_Integer ic;
945 if (tointeger(rb, &ib) && tointeger(rc, &ic)) {
946 setivalue(ra, intop(&, ib, ic));
947 }
948 else { Protect(luaT_trybinTM(L, rb, rc, ra, TM_BAND)); }
949 vmbreak;
950 }
951 vmcase(OP_BOR) {
952 TValue *rb = RKB(i);
953 TValue *rc = RKC(i);
954 lua_Integer ib; lua_Integer ic;
955 if (tointeger(rb, &ib) && tointeger(rc, &ic)) {
956 setivalue(ra, intop(|, ib, ic));
957 }
958 else { Protect(luaT_trybinTM(L, rb, rc, ra, TM_BOR)); }
959 vmbreak;
960 }
961 vmcase(OP_BXOR) {
962 TValue *rb = RKB(i);
963 TValue *rc = RKC(i);
964 lua_Integer ib; lua_Integer ic;
965 if (tointeger(rb, &ib) && tointeger(rc, &ic)) {
966 setivalue(ra, intop(^, ib, ic));
967 }
968 else { Protect(luaT_trybinTM(L, rb, rc, ra, TM_BXOR)); }
969 vmbreak;
970 }
971 vmcase(OP_SHL) {
972 TValue *rb = RKB(i);
973 TValue *rc = RKC(i);
974 lua_Integer ib; lua_Integer ic;
975 if (tointeger(rb, &ib) && tointeger(rc, &ic)) {
976 setivalue(ra, luaV_shiftl(ib, ic));
977 }
978 else { Protect(luaT_trybinTM(L, rb, rc, ra, TM_SHL)); }
979 vmbreak;
980 }
981 vmcase(OP_SHR) {
982 TValue *rb = RKB(i);
983 TValue *rc = RKC(i);
984 lua_Integer ib; lua_Integer ic;
985 if (tointeger(rb, &ib) && tointeger(rc, &ic)) {
986 setivalue(ra, luaV_shiftl(ib, -ic));
987 }
988 else { Protect(luaT_trybinTM(L, rb, rc, ra, TM_SHR)); }
989 vmbreak;
990 }
991 vmcase(OP_MOD) {
992 TValue *rb = RKB(i);
993 TValue *rc = RKC(i);
994 lua_Number nb; lua_Number nc;
995 if (ttisinteger(rb) && ttisinteger(rc)) {
996 lua_Integer ib = ivalue(rb); lua_Integer ic = ivalue(rc);
997 setivalue(ra, luaV_mod(L, ib, ic));
998 }
999 else if (tonumber(rb, &nb) && tonumber(rc, &nc)) {
1000 lua_Number m;
1001 luai_nummod(L, nb, nc, m);
1002 setfltvalue(ra, m);
1003 }
1004 else { Protect(luaT_trybinTM(L, rb, rc, ra, TM_MOD)); }
1005 vmbreak;
1006 }
1007 vmcase(OP_IDIV) { /* floor division */
1008 TValue *rb = RKB(i);
1009 TValue *rc = RKC(i);
1010 lua_Number nb; lua_Number nc;
1011 if (ttisinteger(rb) && ttisinteger(rc)) {
1012 lua_Integer ib = ivalue(rb); lua_Integer ic = ivalue(rc);
1013 setivalue(ra, luaV_div(L, ib, ic));
1014 }
1015 else if (tonumber(rb, &nb) && tonumber(rc, &nc)) {
1016 setfltvalue(ra, luai_numidiv(L, nb, nc));
1017 }
1018 else { Protect(luaT_trybinTM(L, rb, rc, ra, TM_IDIV)); }
1019 vmbreak;
1020 }
1021 vmcase(OP_POW) {
1022 TValue *rb = RKB(i);
1023 TValue *rc = RKC(i);
1024 lua_Number nb; lua_Number nc;
1025 if (tonumber(rb, &nb) && tonumber(rc, &nc)) {
1026 setfltvalue(ra, luai_numpow(L, nb, nc));
1027 }
1028 else { Protect(luaT_trybinTM(L, rb, rc, ra, TM_POW)); }
1029 vmbreak;
1030 }
1031 vmcase(OP_UNM) {
1032 TValue *rb = RB(i);
1033 lua_Number nb;
1034 if (ttisinteger(rb)) {
1035 lua_Integer ib = ivalue(rb);
1036 setivalue(ra, intop(-, 0, ib));
1037 }
1038 else if (tonumber(rb, &nb)) {
1039 setfltvalue(ra, luai_numunm(L, nb));
1040 }
1041 else {
1042 Protect(luaT_trybinTM(L, rb, rb, ra, TM_UNM));
1043 }
1044 vmbreak;
1045 }
1046 vmcase(OP_BNOT) {
1047 TValue *rb = RB(i);
1048 lua_Integer ib;
1049 if (tointeger(rb, &ib)) {
1050 setivalue(ra, intop(^, ~l_castS2U(0), ib));
1051 }
1052 else {
1053 Protect(luaT_trybinTM(L, rb, rb, ra, TM_BNOT));
1054 }
1055 vmbreak;
1056 }
1057 vmcase(OP_NOT) {
1058 TValue *rb = RB(i);
1059 int res = l_isfalse(rb); /* next assignment may change this value */
1060 setbvalue(ra, res);
1061 vmbreak;
1062 }
1063 vmcase(OP_LEN) {
1064 Protect(luaV_objlen(L, ra, RB(i)));
1065 vmbreak;
1066 }
1067 vmcase(OP_CONCAT) {
1068 int b = GETARG_B(i);
1069 int c = GETARG_C(i);
1070 StkId rb;
1071 L->top = base + c + 1; /* mark the end of concat operands */
1072 Protect(luaV_concat(L, c - b + 1));
1073 ra = RA(i); /* 'luaV_concat' may invoke TMs and move the stack */
1074 rb = base + b;
1075 setobjs2s(L, ra, rb);
1076 checkGC(L, (ra >= rb ? ra + 1 : rb));
1077 L->top = ci->top; /* restore top */
1078 vmbreak;
1079 }
1080 vmcase(OP_JMP) {
1081 dojump(ci, i, 0);
1082 vmbreak;
1083 }
1084 vmcase(OP_EQ) {
1085 TValue *rb = RKB(i);
1086 TValue *rc = RKC(i);
1087 Protect(
1088 if (luaV_equalobj(L, rb, rc) != GETARG_A(i))
1089 ci->u.l.savedpc++;
1090 else
1091 donextjump(ci);
1092 )
1093 vmbreak;
1094 }
1095 vmcase(OP_LT) {
1096 Protect(
1097 if (luaV_lessthan(L, RKB(i), RKC(i)) != GETARG_A(i))
1098 ci->u.l.savedpc++;
1099 else
1100 donextjump(ci);
1101 )
1102 vmbreak;
1103 }
1104 vmcase(OP_LE) {
1105 Protect(
1106 if (luaV_lessequal(L, RKB(i), RKC(i)) != GETARG_A(i))
1107 ci->u.l.savedpc++;
1108 else
1109 donextjump(ci);
1110 )
1111 vmbreak;
1112 }
1113 vmcase(OP_TEST) {
1114 if (GETARG_C(i) ? l_isfalse(ra) : !l_isfalse(ra))
1115 ci->u.l.savedpc++;
1116 else
1117 donextjump(ci);
1118 vmbreak;
1119 }
1120 vmcase(OP_TESTSET) {
1121 TValue *rb = RB(i);
1122 if (GETARG_C(i) ? l_isfalse(rb) : !l_isfalse(rb))
1123 ci->u.l.savedpc++;
1124 else {
1125 setobjs2s(L, ra, rb);
1126 donextjump(ci);
1127 }
1128 vmbreak;
1129 }
1130 vmcase(OP_CALL) {
1131 int b = GETARG_B(i);
1132 int nresults = GETARG_C(i) - 1;
1133 if (b != 0) L->top = ra+b; /* else previous instruction set top */
1134 if (luaD_precall(L, ra, nresults)) { /* C function? */
1135 if (nresults >= 0)
1136 L->top = ci->top; /* adjust results */
1137 Protect((void)0); /* update 'base' */
1138 }
1139 else { /* Lua function */
1140 ci = L->ci;
1141 goto newframe; /* restart luaV_execute over new Lua function */
1142 }
1143 vmbreak;
1144 }
1145 vmcase(OP_TAILCALL) {
1146 int b = GETARG_B(i);
1147 if (b != 0) L->top = ra+b; /* else previous instruction set top */
1148 lua_assert(GETARG_C(i) - 1 == LUA_MULTRET);
1149 if (luaD_precall(L, ra, LUA_MULTRET)) { /* C function? */
1150 Protect((void)0); /* update 'base' */
1151 }
1152 else {
1153 /* tail call: put called frame (n) in place of caller one (o) */
1154 CallInfo *nci = L->ci; /* called frame */
1155 CallInfo *oci = nci->previous; /* caller frame */
1156 StkId nfunc = nci->func; /* called function */
1157 StkId ofunc = oci->func; /* caller function */
1158 /* last stack slot filled by 'precall' */
1159 StkId lim = nci->u.l.base + getproto(nfunc)->numparams;
1160 int aux;
1161 /* close all upvalues from previous call */
1162 if (cl->p->sizep > 0) luaF_close(L, oci->u.l.base);
1163 /* move new frame into old one */
1164 for (aux = 0; nfunc + aux < lim; aux++)
1165 setobjs2s(L, ofunc + aux, nfunc + aux);
1166 oci->u.l.base = ofunc + (nci->u.l.base - nfunc); /* correct base */
1167 oci->top = L->top = ofunc + (L->top - nfunc); /* correct top */
1168 oci->u.l.savedpc = nci->u.l.savedpc;
1169 oci->callstatus |= CIST_TAIL; /* function was tail called */
1170 ci = L->ci = oci; /* remove new frame */
1171 lua_assert(L->top == oci->u.l.base + getproto(ofunc)->maxstacksize);
1172 goto newframe; /* restart luaV_execute over new Lua function */
1173 }
1174 vmbreak;
1175 }
1176 vmcase(OP_RETURN) {
1177 int b = GETARG_B(i);
1178 if (cl->p->sizep > 0) luaF_close(L, base);
1179 b = luaD_poscall(L, ci, ra, (b != 0 ? b - 1 : cast_int(L->top - ra)));
1180 if (ci->callstatus & CIST_FRESH) /* local 'ci' still from callee */
1181 return; /* external invocation: return */
1182 else { /* invocation via reentry: continue execution */
1183 ci = L->ci;
1184 if (b) L->top = ci->top;
1185 lua_assert(isLua(ci));
1186 lua_assert(GET_OPCODE(*((ci)->u.l.savedpc - 1)) == OP_CALL);
1187 goto newframe; /* restart luaV_execute over new Lua function */
1188 }
1189 }
1190 vmcase(OP_FORLOOP) {
1191 if (ttisinteger(ra)) { /* integer loop? */
1192 lua_Integer step = ivalue(ra + 2);
1193 lua_Integer idx = intop(+, ivalue(ra), step); /* increment index */
1194 lua_Integer limit = ivalue(ra + 1);
1195 if ((0 < step) ? (idx <= limit) : (limit <= idx)) {
1196 ci->u.l.savedpc += GETARG_sBx(i); /* jump back */
1197 chgivalue(ra, idx); /* update internal index... */
1198 setivalue(ra + 3, idx); /* ...and external index */
1199 }
1200 }
1201 else { /* floating loop */
1202 lua_Number step = fltvalue(ra + 2);
1203 lua_Number idx = luai_numadd(L, fltvalue(ra), step); /* inc. index */
1204 lua_Number limit = fltvalue(ra + 1);
1205 if (luai_numlt(0, step) ? luai_numle(idx, limit)
1206 : luai_numle(limit, idx)) {
1207 ci->u.l.savedpc += GETARG_sBx(i); /* jump back */
1208 chgfltvalue(ra, idx); /* update internal index... */
1209 setfltvalue(ra + 3, idx); /* ...and external index */
1210 }
1211 }
1212 vmbreak;
1213 }
1214 vmcase(OP_FORPREP) {
1215 TValue *init = ra;
1216 TValue *plimit = ra + 1;
1217 TValue *pstep = ra + 2;
1218 lua_Integer ilimit;
1219 int stopnow;
1220 if (ttisinteger(init) && ttisinteger(pstep) &&
1221 forlimit(plimit, &ilimit, ivalue(pstep), &stopnow)) {
1222 /* all values are integer */
1223 lua_Integer initv = (stopnow ? 0 : ivalue(init));
1224 setivalue(plimit, ilimit);
1225 setivalue(init, intop(-, initv, ivalue(pstep)));
1226 }
1227 else { /* try making all values floats */
1228 lua_Number ninit; lua_Number nlimit; lua_Number nstep;
1229 if (!tonumber(plimit, &nlimit))
1230 luaG_runerror(L, "'for' limit must be a number");
1231 setfltvalue(plimit, nlimit);
1232 if (!tonumber(pstep, &nstep))
1233 luaG_runerror(L, "'for' step must be a number");
1234 setfltvalue(pstep, nstep);
1235 if (!tonumber(init, &ninit))
1236 luaG_runerror(L, "'for' initial value must be a number");
1237 setfltvalue(init, luai_numsub(L, ninit, nstep));
1238 }
1239 ci->u.l.savedpc += GETARG_sBx(i);
1240 vmbreak;
1241 }
1242 vmcase(OP_TFORCALL) {
1243 StkId cb = ra + 3; /* call base */
1244 setobjs2s(L, cb+2, ra+2);
1245 setobjs2s(L, cb+1, ra+1);
1246 setobjs2s(L, cb, ra);
1247 L->top = cb + 3; /* func. + 2 args (state and index) */
1248 Protect(luaD_call(L, cb, GETARG_C(i)));
1249 L->top = ci->top;
1250 i = *(ci->u.l.savedpc++); /* go to next instruction */
1251 ra = RA(i);
1252 lua_assert(GET_OPCODE(i) == OP_TFORLOOP);
1253 goto l_tforloop;
1254 }
1255 vmcase(OP_TFORLOOP) {
1256 l_tforloop:
1257 if (!ttisnil(ra + 1)) { /* continue loop? */
1258 setobjs2s(L, ra, ra + 1); /* save control variable */
1259 ci->u.l.savedpc += GETARG_sBx(i); /* jump back */
1260 }
1261 vmbreak;
1262 }
1263 vmcase(OP_SETLIST) {
1264 int n = GETARG_B(i);
1265 int c = GETARG_C(i);
1266 unsigned int last;
1267 Table *h;
1268 if (n == 0) n = cast_int(L->top - ra) - 1;
1269 if (c == 0) {
1270 lua_assert(GET_OPCODE(*ci->u.l.savedpc) == OP_EXTRAARG);
1271 c = GETARG_Ax(*ci->u.l.savedpc++);
1272 }
1273 h = hvalue(ra);
1274 last = ((c-1)*LFIELDS_PER_FLUSH) + n;
1275 if (last > h->sizearray) /* needs more space? */
1276 luaH_resizearray(L, h, last); /* preallocate it at once */
1277 for (; n > 0; n--) {
1278 TValue *val = ra+n;
1279 luaH_setint(L, h, last--, val);
1280 luaC_barrierback(L, h, val);
1281 }
1282 L->top = ci->top; /* correct top (in case of previous open call) */
1283 vmbreak;
1284 }
1285 vmcase(OP_CLOSURE) {
1286 Proto *p = cl->p->p[GETARG_Bx(i)];
1287 LClosure *ncl = getcached(p, cl->upvals, base); /* cached closure */
1288 if (ncl == NULL) /* no match? */
1289 pushclosure(L, p, cl->upvals, base, ra); /* create a new one */
1290 else
1291 setclLvalue(L, ra, ncl); /* push cashed closure */
1292 checkGC(L, ra + 1);
1293 vmbreak;
1294 }
1295 vmcase(OP_VARARG) {
1296 int b = GETARG_B(i) - 1; /* required results */
1297 int j;
1298 int n = cast_int(base - ci->func) - cl->p->numparams - 1;
1299 if (n < 0) /* less arguments than parameters? */
1300 n = 0; /* no vararg arguments */
1301 if (b < 0) { /* B == 0? */
1302 b = n; /* get all var. arguments */
1303 Protect(luaD_checkstack(L, n));
1304 ra = RA(i); /* previous call may change the stack */
1305 L->top = ra + n;
1306 }
1307 for (j = 0; j < b && j < n; j++)
1308 setobjs2s(L, ra + j, base - n + j);
1309 for (; j < b; j++) /* complete required results with nil */
1310 setnilvalue(ra + j);
1311 vmbreak;
1312 }
1313 vmcase(OP_EXTRAARG) {
1314 lua_assert(0);
1315 vmbreak;
1316 }
1317 }
1318 }
1319}
1320
1321/* }================================================================== */
1322
1323