xref: /freebsd/contrib/lua/src/lvm.c (revision 3068d706eabe99f930fb01d3cbfd74ff1f0eb5a2)
1 /*
2 ** $Id: lvm.c $
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 /*
35 ** By default, use jump tables in the main interpreter loop on gcc
36 ** and compatible compilers.
37 */
38 #if !defined(LUA_USE_JUMPTABLE)
39 #if defined(__GNUC__)
40 #define LUA_USE_JUMPTABLE	1
41 #else
42 #define LUA_USE_JUMPTABLE	0
43 #endif
44 #endif
45 
46 
47 
48 /* limit for table tag-method chains (to avoid infinite loops) */
49 #define MAXTAGLOOP	2000
50 
51 
52 /*
53 ** 'l_intfitsf' checks whether a given integer is in the range that
54 ** can be converted to a float without rounding. Used in comparisons.
55 ** May be defined in luaconf.h if this test is incorrect for custom
56 ** LUA_FLOAT_TYPEs.
57 */
58 #if !defined(l_intfitsf)
59 
60 /* number of bits in the mantissa of a float */
61 #define NBM		(l_floatatt(MANT_DIG))
62 
63 /*
64 ** Check whether some integers may not fit in a float, testing whether
65 ** (maxinteger >> NBM) > 0. (That implies (1 << NBM) <= maxinteger.)
66 ** (The shifts are done in parts, to avoid shifting by more than the size
67 ** of an integer. In a worst case, NBM == 113 for long double and
68 ** sizeof(long) == 32.)
69 */
70 #if ((((LUA_MAXINTEGER >> (NBM / 4)) >> (NBM / 4)) >> (NBM / 4)) \
71 	>> (NBM - (3 * (NBM / 4))))  >  0
72 
73 /* limit for integers that fit in a float */
74 #define MAXINTFITSF	((lua_Unsigned)1 << NBM)
75 
76 /* check whether 'i' is in the interval [-MAXINTFITSF, MAXINTFITSF] */
77 #define l_intfitsf(i)	((MAXINTFITSF + l_castS2U(i)) <= (2 * MAXINTFITSF))
78 
79 #else  /* all integers fit in a float precisely */
80 
81 #define l_intfitsf(i)	1
82 
83 #endif
84 
85 #endif /* !defined(l_intfitsf) */
86 
87 /*
88 ** Try to convert a value from string to a number value.
89 ** If the value is not a string or is a string not representing
90 ** a valid numeral (or if coercions from strings to numbers
91 ** are disabled via macro 'cvt2num'), do not modify 'result'
92 ** and return 0.
93 */
l_strton(const TValue * obj,TValue * result)94 static int l_strton (const TValue *obj, TValue *result) {
95   lua_assert(obj != result);
96   if (!cvt2num(obj))  /* is object not a string? */
97     return 0;
98   else {
99     TString *st = tsvalue(obj);
100     return (luaO_str2num(getstr(st), result) == tsslen(st) + 1);
101   }
102 }
103 
104 
105 /*
106 ** Try to convert a value to a float. The float case is already handled
107 ** by the macro 'tonumber'.
108 */
luaV_tonumber_(const TValue * obj,lua_Number * n)109 int luaV_tonumber_ (const TValue *obj, lua_Number *n) {
110   TValue v;
111   if (ttisinteger(obj)) {
112     *n = cast_num(ivalue(obj));
113     return 1;
114   }
115   else if (l_strton(obj, &v)) {  /* string coercible to number? */
116     *n = nvalue(&v);  /* convert result of 'luaO_str2num' to a float */
117     return 1;
118   }
119   else
120     return 0;  /* conversion failed */
121 }
122 
123 
124 /*
125 ** try to convert a float to an integer, rounding according to 'mode'.
126 */
luaV_flttointeger(lua_Number n,lua_Integer * p,F2Imod mode)127 int luaV_flttointeger (lua_Number n, lua_Integer *p, F2Imod mode) {
128   lua_Number f = l_floor(n);
129   if (n != f) {  /* not an integral value? */
130     if (mode == F2Ieq) return 0;  /* fails if mode demands integral value */
131     else if (mode == F2Iceil)  /* needs ceil? */
132       f += 1;  /* convert floor to ceil (remember: n != f) */
133   }
134   return lua_numbertointeger(f, p);
135 }
136 
137 
138 /*
139 ** try to convert a value to an integer, rounding according to 'mode',
140 ** without string coercion.
141 ** ("Fast track" handled by macro 'tointegerns'.)
142 */
luaV_tointegerns(const TValue * obj,lua_Integer * p,F2Imod mode)143 int luaV_tointegerns (const TValue *obj, lua_Integer *p, F2Imod mode) {
144   if (ttisfloat(obj))
145     return luaV_flttointeger(fltvalue(obj), p, mode);
146   else if (ttisinteger(obj)) {
147     *p = ivalue(obj);
148     return 1;
149   }
150   else
151     return 0;
152 }
153 
154 
155 /*
156 ** try to convert a value to an integer.
157 */
luaV_tointeger(const TValue * obj,lua_Integer * p,F2Imod mode)158 int luaV_tointeger (const TValue *obj, lua_Integer *p, F2Imod mode) {
159   TValue v;
160   if (l_strton(obj, &v))  /* does 'obj' point to a numerical string? */
161     obj = &v;  /* change it to point to its corresponding number */
162   return luaV_tointegerns(obj, p, mode);
163 }
164 
165 
166 /*
167 ** Try to convert a 'for' limit to an integer, preserving the semantics
168 ** of the loop. Return true if the loop must not run; otherwise, '*p'
169 ** gets the integer limit.
170 ** (The following explanation assumes a positive step; it is valid for
171 ** negative steps mutatis mutandis.)
172 ** If the limit is an integer or can be converted to an integer,
173 ** rounding down, that is the limit.
174 ** Otherwise, check whether the limit can be converted to a float. If
175 ** the float is too large, clip it to LUA_MAXINTEGER.  If the float
176 ** is too negative, the loop should not run, because any initial
177 ** integer value is greater than such limit; so, the function returns
178 ** true to signal that. (For this latter case, no integer limit would be
179 ** correct; even a limit of LUA_MININTEGER would run the loop once for
180 ** an initial value equal to LUA_MININTEGER.)
181 */
forlimit(lua_State * L,lua_Integer init,const TValue * lim,lua_Integer * p,lua_Integer step)182 static int forlimit (lua_State *L, lua_Integer init, const TValue *lim,
183                                    lua_Integer *p, lua_Integer step) {
184   if (!luaV_tointeger(lim, p, (step < 0 ? F2Iceil : F2Ifloor))) {
185     /* not coercible to in integer */
186     lua_Number flim;  /* try to convert to float */
187     if (!tonumber(lim, &flim)) /* cannot convert to float? */
188       luaG_forerror(L, lim, "limit");
189     /* else 'flim' is a float out of integer bounds */
190     if (luai_numlt(0, flim)) {  /* if it is positive, it is too large */
191       if (step < 0) return 1;  /* initial value must be less than it */
192       *p = LUA_MAXINTEGER;  /* truncate */
193     }
194     else {  /* it is less than min integer */
195       if (step > 0) return 1;  /* initial value must be greater than it */
196       *p = LUA_MININTEGER;  /* truncate */
197     }
198   }
199   return (step > 0 ? init > *p : init < *p);  /* not to run? */
200 }
201 
202 
203 /*
204 ** Prepare a numerical for loop (opcode OP_FORPREP).
205 ** Return true to skip the loop. Otherwise,
206 ** after preparation, stack will be as follows:
207 **   ra : internal index (safe copy of the control variable)
208 **   ra + 1 : loop counter (integer loops) or limit (float loops)
209 **   ra + 2 : step
210 **   ra + 3 : control variable
211 */
forprep(lua_State * L,StkId ra)212 static int forprep (lua_State *L, StkId ra) {
213   TValue *pinit = s2v(ra);
214   TValue *plimit = s2v(ra + 1);
215   TValue *pstep = s2v(ra + 2);
216   if (ttisinteger(pinit) && ttisinteger(pstep)) { /* integer loop? */
217     lua_Integer init = ivalue(pinit);
218     lua_Integer step = ivalue(pstep);
219     lua_Integer limit;
220     if (step == 0)
221       luaG_runerror(L, "'for' step is zero");
222     setivalue(s2v(ra + 3), init);  /* control variable */
223     if (forlimit(L, init, plimit, &limit, step))
224       return 1;  /* skip the loop */
225     else {  /* prepare loop counter */
226       lua_Unsigned count;
227       if (step > 0) {  /* ascending loop? */
228         count = l_castS2U(limit) - l_castS2U(init);
229         if (step != 1)  /* avoid division in the too common case */
230           count /= l_castS2U(step);
231       }
232       else {  /* step < 0; descending loop */
233         count = l_castS2U(init) - l_castS2U(limit);
234         /* 'step+1' avoids negating 'mininteger' */
235         count /= l_castS2U(-(step + 1)) + 1u;
236       }
237       /* store the counter in place of the limit (which won't be
238          needed anymore) */
239       setivalue(plimit, l_castU2S(count));
240     }
241   }
242   else {  /* try making all values floats */
243     lua_Number init; lua_Number limit; lua_Number step;
244     if (l_unlikely(!tonumber(plimit, &limit)))
245       luaG_forerror(L, plimit, "limit");
246     if (l_unlikely(!tonumber(pstep, &step)))
247       luaG_forerror(L, pstep, "step");
248     if (l_unlikely(!tonumber(pinit, &init)))
249       luaG_forerror(L, pinit, "initial value");
250     if (step == 0)
251       luaG_runerror(L, "'for' step is zero");
252     if (luai_numlt(0, step) ? luai_numlt(limit, init)
253                             : luai_numlt(init, limit))
254       return 1;  /* skip the loop */
255     else {
256       /* make sure internal values are all floats */
257       setfltvalue(plimit, limit);
258       setfltvalue(pstep, step);
259       setfltvalue(s2v(ra), init);  /* internal index */
260       setfltvalue(s2v(ra + 3), init);  /* control variable */
261     }
262   }
263   return 0;
264 }
265 
266 
267 /*
268 ** Execute a step of a float numerical for loop, returning
269 ** true iff the loop must continue. (The integer case is
270 ** written online with opcode OP_FORLOOP, for performance.)
271 */
floatforloop(StkId ra)272 static int floatforloop (StkId ra) {
273   lua_Number step = fltvalue(s2v(ra + 2));
274   lua_Number limit = fltvalue(s2v(ra + 1));
275   lua_Number idx = fltvalue(s2v(ra));  /* internal index */
276   idx = luai_numadd(L, idx, step);  /* increment index */
277   if (luai_numlt(0, step) ? luai_numle(idx, limit)
278                           : luai_numle(limit, idx)) {
279     chgfltvalue(s2v(ra), idx);  /* update internal index */
280     setfltvalue(s2v(ra + 3), idx);  /* and control variable */
281     return 1;  /* jump back */
282   }
283   else
284     return 0;  /* finish the loop */
285 }
286 
287 
288 /*
289 ** Finish the table access 'val = t[key]'.
290 ** if 'slot' is NULL, 't' is not a table; otherwise, 'slot' points to
291 ** t[k] entry (which must be empty).
292 */
luaV_finishget(lua_State * L,const TValue * t,TValue * key,StkId val,const TValue * slot)293 void luaV_finishget (lua_State *L, const TValue *t, TValue *key, StkId val,
294                       const TValue *slot) {
295   int loop;  /* counter to avoid infinite loops */
296   const TValue *tm;  /* metamethod */
297   for (loop = 0; loop < MAXTAGLOOP; loop++) {
298     if (slot == NULL) {  /* 't' is not a table? */
299       lua_assert(!ttistable(t));
300       tm = luaT_gettmbyobj(L, t, TM_INDEX);
301       if (l_unlikely(notm(tm)))
302         luaG_typeerror(L, t, "index");  /* no metamethod */
303       /* else will try the metamethod */
304     }
305     else {  /* 't' is a table */
306       lua_assert(isempty(slot));
307       tm = fasttm(L, hvalue(t)->metatable, TM_INDEX);  /* table's metamethod */
308       if (tm == NULL) {  /* no metamethod? */
309         setnilvalue(s2v(val));  /* result is nil */
310         return;
311       }
312       /* else will try the metamethod */
313     }
314     if (ttisfunction(tm)) {  /* is metamethod a function? */
315       luaT_callTMres(L, tm, t, key, val);  /* call it */
316       return;
317     }
318     t = tm;  /* else try to access 'tm[key]' */
319     if (luaV_fastget(L, t, key, slot, luaH_get)) {  /* fast track? */
320       setobj2s(L, val, slot);  /* done */
321       return;
322     }
323     /* else repeat (tail call 'luaV_finishget') */
324   }
325   luaG_runerror(L, "'__index' chain too long; possible loop");
326 }
327 
328 
329 /*
330 ** Finish a table assignment 't[key] = val'.
331 ** If 'slot' is NULL, 't' is not a table.  Otherwise, 'slot' points
332 ** to the entry 't[key]', or to a value with an absent key if there
333 ** is no such entry.  (The value at 'slot' must be empty, otherwise
334 ** 'luaV_fastget' would have done the job.)
335 */
luaV_finishset(lua_State * L,const TValue * t,TValue * key,TValue * val,const TValue * slot)336 void luaV_finishset (lua_State *L, const TValue *t, TValue *key,
337                      TValue *val, const TValue *slot) {
338   int loop;  /* counter to avoid infinite loops */
339   for (loop = 0; loop < MAXTAGLOOP; loop++) {
340     const TValue *tm;  /* '__newindex' metamethod */
341     if (slot != NULL) {  /* is 't' a table? */
342       Table *h = hvalue(t);  /* save 't' table */
343       lua_assert(isempty(slot));  /* slot must be empty */
344       tm = fasttm(L, h->metatable, TM_NEWINDEX);  /* get metamethod */
345       if (tm == NULL) {  /* no metamethod? */
346         sethvalue2s(L, L->top.p, h);  /* anchor 't' */
347         L->top.p++;  /* assume EXTRA_STACK */
348         luaH_finishset(L, h, key, slot, val);  /* set new value */
349         L->top.p--;
350         invalidateTMcache(h);
351         luaC_barrierback(L, obj2gco(h), val);
352         return;
353       }
354       /* else will try the metamethod */
355     }
356     else {  /* not a table; check metamethod */
357       tm = luaT_gettmbyobj(L, t, TM_NEWINDEX);
358       if (l_unlikely(notm(tm)))
359         luaG_typeerror(L, t, "index");
360     }
361     /* try the metamethod */
362     if (ttisfunction(tm)) {
363       luaT_callTM(L, tm, t, key, val);
364       return;
365     }
366     t = tm;  /* else repeat assignment over 'tm' */
367     if (luaV_fastget(L, t, key, slot, luaH_get)) {
368       luaV_finishfastset(L, t, slot, val);
369       return;  /* done */
370     }
371     /* else 'return luaV_finishset(L, t, key, val, slot)' (loop) */
372   }
373   luaG_runerror(L, "'__newindex' chain too long; possible loop");
374 }
375 
376 
377 /*
378 ** Compare two strings 'ts1' x 'ts2', returning an integer less-equal-
379 ** -greater than zero if 'ts1' is less-equal-greater than 'ts2'.
380 ** The code is a little tricky because it allows '\0' in the strings
381 ** and it uses 'strcoll' (to respect locales) for each segment
382 ** of the strings. Note that segments can compare equal but still
383 ** have different lengths.
384 */
l_strcmp(const TString * ts1,const TString * ts2)385 static int l_strcmp (const TString *ts1, const TString *ts2) {
386   const char *s1 = getstr(ts1);
387   size_t rl1 = tsslen(ts1);  /* real length */
388   const char *s2 = getstr(ts2);
389   size_t rl2 = tsslen(ts2);
390   for (;;) {  /* for each segment */
391     int temp = strcoll(s1, s2);
392     if (temp != 0)  /* not equal? */
393       return temp;  /* done */
394     else {  /* strings are equal up to a '\0' */
395       size_t zl1 = strlen(s1);  /* index of first '\0' in 's1' */
396       size_t zl2 = strlen(s2);  /* index of first '\0' in 's2' */
397       if (zl2 == rl2)  /* 's2' is finished? */
398         return (zl1 == rl1) ? 0 : 1;  /* check 's1' */
399       else if (zl1 == rl1)  /* 's1' is finished? */
400         return -1;  /* 's1' is less than 's2' ('s2' is not finished) */
401       /* both strings longer than 'zl'; go on comparing after the '\0' */
402       zl1++; zl2++;
403       s1 += zl1; rl1 -= zl1; s2 += zl2; rl2 -= zl2;
404     }
405   }
406 }
407 
408 
409 /*
410 ** Check whether integer 'i' is less than float 'f'. If 'i' has an
411 ** exact representation as a float ('l_intfitsf'), compare numbers as
412 ** floats. Otherwise, use the equivalence 'i < f <=> i < ceil(f)'.
413 ** If 'ceil(f)' is out of integer range, either 'f' is greater than
414 ** all integers or less than all integers.
415 ** (The test with 'l_intfitsf' is only for performance; the else
416 ** case is correct for all values, but it is slow due to the conversion
417 ** from float to int.)
418 ** When 'f' is NaN, comparisons must result in false.
419 */
LTintfloat(lua_Integer i,lua_Number f)420 l_sinline int LTintfloat (lua_Integer i, lua_Number f) {
421   if (l_intfitsf(i))
422     return luai_numlt(cast_num(i), f);  /* compare them as floats */
423   else {  /* i < f <=> i < ceil(f) */
424     lua_Integer fi;
425     if (luaV_flttointeger(f, &fi, F2Iceil))  /* fi = ceil(f) */
426       return i < fi;   /* compare them as integers */
427     else  /* 'f' is either greater or less than all integers */
428       return f > 0;  /* greater? */
429   }
430 }
431 
432 
433 /*
434 ** Check whether integer 'i' is less than or equal to float 'f'.
435 ** See comments on previous function.
436 */
LEintfloat(lua_Integer i,lua_Number f)437 l_sinline int LEintfloat (lua_Integer i, lua_Number f) {
438   if (l_intfitsf(i))
439     return luai_numle(cast_num(i), f);  /* compare them as floats */
440   else {  /* i <= f <=> i <= floor(f) */
441     lua_Integer fi;
442     if (luaV_flttointeger(f, &fi, F2Ifloor))  /* fi = floor(f) */
443       return i <= fi;   /* compare them as integers */
444     else  /* 'f' is either greater or less than all integers */
445       return f > 0;  /* greater? */
446   }
447 }
448 
449 
450 /*
451 ** Check whether float 'f' is less than integer 'i'.
452 ** See comments on previous function.
453 */
LTfloatint(lua_Number f,lua_Integer i)454 l_sinline int LTfloatint (lua_Number f, lua_Integer i) {
455   if (l_intfitsf(i))
456     return luai_numlt(f, cast_num(i));  /* compare them as floats */
457   else {  /* f < i <=> floor(f) < i */
458     lua_Integer fi;
459     if (luaV_flttointeger(f, &fi, F2Ifloor))  /* fi = floor(f) */
460       return fi < i;   /* compare them as integers */
461     else  /* 'f' is either greater or less than all integers */
462       return f < 0;  /* less? */
463   }
464 }
465 
466 
467 /*
468 ** Check whether float 'f' is less than or equal to integer 'i'.
469 ** See comments on previous function.
470 */
LEfloatint(lua_Number f,lua_Integer i)471 l_sinline int LEfloatint (lua_Number f, lua_Integer i) {
472   if (l_intfitsf(i))
473     return luai_numle(f, cast_num(i));  /* compare them as floats */
474   else {  /* f <= i <=> ceil(f) <= i */
475     lua_Integer fi;
476     if (luaV_flttointeger(f, &fi, F2Iceil))  /* fi = ceil(f) */
477       return fi <= i;   /* compare them as integers */
478     else  /* 'f' is either greater or less than all integers */
479       return f < 0;  /* less? */
480   }
481 }
482 
483 
484 /*
485 ** Return 'l < r', for numbers.
486 */
LTnum(const TValue * l,const TValue * r)487 l_sinline int LTnum (const TValue *l, const TValue *r) {
488   lua_assert(ttisnumber(l) && ttisnumber(r));
489   if (ttisinteger(l)) {
490     lua_Integer li = ivalue(l);
491     if (ttisinteger(r))
492       return li < ivalue(r);  /* both are integers */
493     else  /* 'l' is int and 'r' is float */
494       return LTintfloat(li, fltvalue(r));  /* l < r ? */
495   }
496   else {
497     lua_Number lf = fltvalue(l);  /* 'l' must be float */
498     if (ttisfloat(r))
499       return luai_numlt(lf, fltvalue(r));  /* both are float */
500     else  /* 'l' is float and 'r' is int */
501       return LTfloatint(lf, ivalue(r));
502   }
503 }
504 
505 
506 /*
507 ** Return 'l <= r', for numbers.
508 */
LEnum(const TValue * l,const TValue * r)509 l_sinline int LEnum (const TValue *l, const TValue *r) {
510   lua_assert(ttisnumber(l) && ttisnumber(r));
511   if (ttisinteger(l)) {
512     lua_Integer li = ivalue(l);
513     if (ttisinteger(r))
514       return li <= ivalue(r);  /* both are integers */
515     else  /* 'l' is int and 'r' is float */
516       return LEintfloat(li, fltvalue(r));  /* l <= r ? */
517   }
518   else {
519     lua_Number lf = fltvalue(l);  /* 'l' must be float */
520     if (ttisfloat(r))
521       return luai_numle(lf, fltvalue(r));  /* both are float */
522     else  /* 'l' is float and 'r' is int */
523       return LEfloatint(lf, ivalue(r));
524   }
525 }
526 
527 
528 /*
529 ** return 'l < r' for non-numbers.
530 */
lessthanothers(lua_State * L,const TValue * l,const TValue * r)531 static int lessthanothers (lua_State *L, const TValue *l, const TValue *r) {
532   lua_assert(!ttisnumber(l) || !ttisnumber(r));
533   if (ttisstring(l) && ttisstring(r))  /* both are strings? */
534     return l_strcmp(tsvalue(l), tsvalue(r)) < 0;
535   else
536     return luaT_callorderTM(L, l, r, TM_LT);
537 }
538 
539 
540 /*
541 ** Main operation less than; return 'l < r'.
542 */
luaV_lessthan(lua_State * L,const TValue * l,const TValue * r)543 int luaV_lessthan (lua_State *L, const TValue *l, const TValue *r) {
544   if (ttisnumber(l) && ttisnumber(r))  /* both operands are numbers? */
545     return LTnum(l, r);
546   else return lessthanothers(L, l, r);
547 }
548 
549 
550 /*
551 ** return 'l <= r' for non-numbers.
552 */
lessequalothers(lua_State * L,const TValue * l,const TValue * r)553 static int lessequalothers (lua_State *L, const TValue *l, const TValue *r) {
554   lua_assert(!ttisnumber(l) || !ttisnumber(r));
555   if (ttisstring(l) && ttisstring(r))  /* both are strings? */
556     return l_strcmp(tsvalue(l), tsvalue(r)) <= 0;
557   else
558     return luaT_callorderTM(L, l, r, TM_LE);
559 }
560 
561 
562 /*
563 ** Main operation less than or equal to; return 'l <= r'.
564 */
luaV_lessequal(lua_State * L,const TValue * l,const TValue * r)565 int luaV_lessequal (lua_State *L, const TValue *l, const TValue *r) {
566   if (ttisnumber(l) && ttisnumber(r))  /* both operands are numbers? */
567     return LEnum(l, r);
568   else return lessequalothers(L, l, r);
569 }
570 
571 
572 /*
573 ** Main operation for equality of Lua values; return 't1 == t2'.
574 ** L == NULL means raw equality (no metamethods)
575 */
luaV_equalobj(lua_State * L,const TValue * t1,const TValue * t2)576 int luaV_equalobj (lua_State *L, const TValue *t1, const TValue *t2) {
577   const TValue *tm;
578   if (ttypetag(t1) != ttypetag(t2)) {  /* not the same variant? */
579     if (ttype(t1) != ttype(t2) || ttype(t1) != LUA_TNUMBER)
580       return 0;  /* only numbers can be equal with different variants */
581     else {  /* two numbers with different variants */
582       /* One of them is an integer. If the other does not have an
583          integer value, they cannot be equal; otherwise, compare their
584          integer values. */
585       lua_Integer i1, i2;
586       return (luaV_tointegerns(t1, &i1, F2Ieq) &&
587               luaV_tointegerns(t2, &i2, F2Ieq) &&
588               i1 == i2);
589     }
590   }
591   /* values have same type and same variant */
592   switch (ttypetag(t1)) {
593     case LUA_VNIL: case LUA_VFALSE: case LUA_VTRUE: return 1;
594     case LUA_VNUMINT: return (ivalue(t1) == ivalue(t2));
595     case LUA_VNUMFLT: return luai_numeq(fltvalue(t1), fltvalue(t2));
596     case LUA_VLIGHTUSERDATA: return pvalue(t1) == pvalue(t2);
597     case LUA_VLCF: return fvalue(t1) == fvalue(t2);
598     case LUA_VSHRSTR: return eqshrstr(tsvalue(t1), tsvalue(t2));
599     case LUA_VLNGSTR: return luaS_eqlngstr(tsvalue(t1), tsvalue(t2));
600     case LUA_VUSERDATA: {
601       if (uvalue(t1) == uvalue(t2)) return 1;
602       else if (L == NULL) return 0;
603       tm = fasttm(L, uvalue(t1)->metatable, TM_EQ);
604       if (tm == NULL)
605         tm = fasttm(L, uvalue(t2)->metatable, TM_EQ);
606       break;  /* will try TM */
607     }
608     case LUA_VTABLE: {
609       if (hvalue(t1) == hvalue(t2)) return 1;
610       else if (L == NULL) return 0;
611       tm = fasttm(L, hvalue(t1)->metatable, TM_EQ);
612       if (tm == NULL)
613         tm = fasttm(L, hvalue(t2)->metatable, TM_EQ);
614       break;  /* will try TM */
615     }
616     default:
617       return gcvalue(t1) == gcvalue(t2);
618   }
619   if (tm == NULL)  /* no TM? */
620     return 0;  /* objects are different */
621   else {
622     luaT_callTMres(L, tm, t1, t2, L->top.p);  /* call TM */
623     return !l_isfalse(s2v(L->top.p));
624   }
625 }
626 
627 
628 /* macro used by 'luaV_concat' to ensure that element at 'o' is a string */
629 #define tostring(L,o)  \
630 	(ttisstring(o) || (cvt2str(o) && (luaO_tostring(L, o), 1)))
631 
632 #define isemptystr(o)	(ttisshrstring(o) && tsvalue(o)->shrlen == 0)
633 
634 /* copy strings in stack from top - n up to top - 1 to buffer */
copy2buff(StkId top,int n,char * buff)635 static void copy2buff (StkId top, int n, char *buff) {
636   size_t tl = 0;  /* size already copied */
637   do {
638     TString *st = tsvalue(s2v(top - n));
639     size_t l = tsslen(st);  /* length of string being copied */
640     memcpy(buff + tl, getstr(st), l * sizeof(char));
641     tl += l;
642   } while (--n > 0);
643 }
644 
645 
646 /*
647 ** Main operation for concatenation: concat 'total' values in the stack,
648 ** from 'L->top.p - total' up to 'L->top.p - 1'.
649 */
luaV_concat(lua_State * L,int total)650 void luaV_concat (lua_State *L, int total) {
651   if (total == 1)
652     return;  /* "all" values already concatenated */
653   do {
654     StkId top = L->top.p;
655     int n = 2;  /* number of elements handled in this pass (at least 2) */
656     if (!(ttisstring(s2v(top - 2)) || cvt2str(s2v(top - 2))) ||
657         !tostring(L, s2v(top - 1)))
658       luaT_tryconcatTM(L);  /* may invalidate 'top' */
659     else if (isemptystr(s2v(top - 1)))  /* second operand is empty? */
660       cast_void(tostring(L, s2v(top - 2)));  /* result is first operand */
661     else if (isemptystr(s2v(top - 2))) {  /* first operand is empty string? */
662       setobjs2s(L, top - 2, top - 1);  /* result is second op. */
663     }
664     else {
665       /* at least two non-empty string values; get as many as possible */
666       size_t tl = tsslen(tsvalue(s2v(top - 1)));
667       TString *ts;
668       /* collect total length and number of strings */
669       for (n = 1; n < total && tostring(L, s2v(top - n - 1)); n++) {
670         size_t l = tsslen(tsvalue(s2v(top - n - 1)));
671         if (l_unlikely(l >= MAX_SIZE - sizeof(TString) - tl)) {
672           L->top.p = top - total;  /* pop strings to avoid wasting stack */
673           luaG_runerror(L, "string length overflow");
674         }
675         tl += l;
676       }
677       if (tl <= LUAI_MAXSHORTLEN) {  /* is result a short string? */
678         char buff[LUAI_MAXSHORTLEN];
679         copy2buff(top, n, buff);  /* copy strings to buffer */
680         ts = luaS_newlstr(L, buff, tl);
681       }
682       else {  /* long string; copy strings directly to final result */
683         ts = luaS_createlngstrobj(L, tl);
684         copy2buff(top, n, getlngstr(ts));
685       }
686       setsvalue2s(L, top - n, ts);  /* create result */
687     }
688     total -= n - 1;  /* got 'n' strings to create one new */
689     L->top.p -= n - 1;  /* popped 'n' strings and pushed one */
690   } while (total > 1);  /* repeat until only 1 result left */
691 }
692 
693 
694 /*
695 ** Main operation 'ra = #rb'.
696 */
luaV_objlen(lua_State * L,StkId ra,const TValue * rb)697 void luaV_objlen (lua_State *L, StkId ra, const TValue *rb) {
698   const TValue *tm;
699   switch (ttypetag(rb)) {
700     case LUA_VTABLE: {
701       Table *h = hvalue(rb);
702       tm = fasttm(L, h->metatable, TM_LEN);
703       if (tm) break;  /* metamethod? break switch to call it */
704       setivalue(s2v(ra), luaH_getn(h));  /* else primitive len */
705       return;
706     }
707     case LUA_VSHRSTR: {
708       setivalue(s2v(ra), tsvalue(rb)->shrlen);
709       return;
710     }
711     case LUA_VLNGSTR: {
712       setivalue(s2v(ra), tsvalue(rb)->u.lnglen);
713       return;
714     }
715     default: {  /* try metamethod */
716       tm = luaT_gettmbyobj(L, rb, TM_LEN);
717       if (l_unlikely(notm(tm)))  /* no metamethod? */
718         luaG_typeerror(L, rb, "get length of");
719       break;
720     }
721   }
722   luaT_callTMres(L, tm, rb, rb, ra);
723 }
724 
725 
726 /*
727 ** Integer division; return 'm // n', that is, floor(m/n).
728 ** C division truncates its result (rounds towards zero).
729 ** 'floor(q) == trunc(q)' when 'q >= 0' or when 'q' is integer,
730 ** otherwise 'floor(q) == trunc(q) - 1'.
731 */
luaV_idiv(lua_State * L,lua_Integer m,lua_Integer n)732 lua_Integer luaV_idiv (lua_State *L, lua_Integer m, lua_Integer n) {
733   if (l_unlikely(l_castS2U(n) + 1u <= 1u)) {  /* special cases: -1 or 0 */
734     if (n == 0)
735       luaG_runerror(L, "attempt to divide by zero");
736     return intop(-, 0, m);   /* n==-1; avoid overflow with 0x80000...//-1 */
737   }
738   else {
739     lua_Integer q = m / n;  /* perform C division */
740     if ((m ^ n) < 0 && m % n != 0)  /* 'm/n' would be negative non-integer? */
741       q -= 1;  /* correct result for different rounding */
742     return q;
743   }
744 }
745 
746 
747 /*
748 ** Integer modulus; return 'm % n'. (Assume that C '%' with
749 ** negative operands follows C99 behavior. See previous comment
750 ** about luaV_idiv.)
751 */
luaV_mod(lua_State * L,lua_Integer m,lua_Integer n)752 lua_Integer luaV_mod (lua_State *L, lua_Integer m, lua_Integer n) {
753   if (l_unlikely(l_castS2U(n) + 1u <= 1u)) {  /* special cases: -1 or 0 */
754     if (n == 0)
755       luaG_runerror(L, "attempt to perform 'n%%0'");
756     return 0;   /* m % -1 == 0; avoid overflow with 0x80000...%-1 */
757   }
758   else {
759     lua_Integer r = m % n;
760     if (r != 0 && (r ^ n) < 0)  /* 'm/n' would be non-integer negative? */
761       r += n;  /* correct result for different rounding */
762     return r;
763   }
764 }
765 
766 
767 /*
768 ** Float modulus
769 */
luaV_modf(lua_State * L,lua_Number m,lua_Number n)770 lua_Number luaV_modf (lua_State *L, lua_Number m, lua_Number n) {
771   lua_Number r;
772   luai_nummod(L, m, n, r);
773   return r;
774 }
775 
776 
777 /* number of bits in an integer */
778 #define NBITS	cast_int(sizeof(lua_Integer) * CHAR_BIT)
779 
780 
781 /*
782 ** Shift left operation. (Shift right just negates 'y'.)
783 */
luaV_shiftl(lua_Integer x,lua_Integer y)784 lua_Integer luaV_shiftl (lua_Integer x, lua_Integer y) {
785   if (y < 0) {  /* shift right? */
786     if (y <= -NBITS) return 0;
787     else return intop(>>, x, -y);
788   }
789   else {  /* shift left */
790     if (y >= NBITS) return 0;
791     else return intop(<<, x, y);
792   }
793 }
794 
795 
796 /*
797 ** create a new Lua closure, push it in the stack, and initialize
798 ** its upvalues.
799 */
pushclosure(lua_State * L,Proto * p,UpVal ** encup,StkId base,StkId ra)800 static void pushclosure (lua_State *L, Proto *p, UpVal **encup, StkId base,
801                          StkId ra) {
802   int nup = p->sizeupvalues;
803   Upvaldesc *uv = p->upvalues;
804   int i;
805   LClosure *ncl = luaF_newLclosure(L, nup);
806   ncl->p = p;
807   setclLvalue2s(L, ra, ncl);  /* anchor new closure in stack */
808   for (i = 0; i < nup; i++) {  /* fill in its upvalues */
809     if (uv[i].instack)  /* upvalue refers to local variable? */
810       ncl->upvals[i] = luaF_findupval(L, base + uv[i].idx);
811     else  /* get upvalue from enclosing function */
812       ncl->upvals[i] = encup[uv[i].idx];
813     luaC_objbarrier(L, ncl, ncl->upvals[i]);
814   }
815 }
816 
817 
818 /*
819 ** finish execution of an opcode interrupted by a yield
820 */
luaV_finishOp(lua_State * L)821 void luaV_finishOp (lua_State *L) {
822   CallInfo *ci = L->ci;
823   StkId base = ci->func.p + 1;
824   Instruction inst = *(ci->u.l.savedpc - 1);  /* interrupted instruction */
825   OpCode op = GET_OPCODE(inst);
826   switch (op) {  /* finish its execution */
827     case OP_MMBIN: case OP_MMBINI: case OP_MMBINK: {
828       setobjs2s(L, base + GETARG_A(*(ci->u.l.savedpc - 2)), --L->top.p);
829       break;
830     }
831     case OP_UNM: case OP_BNOT: case OP_LEN:
832     case OP_GETTABUP: case OP_GETTABLE: case OP_GETI:
833     case OP_GETFIELD: case OP_SELF: {
834       setobjs2s(L, base + GETARG_A(inst), --L->top.p);
835       break;
836     }
837     case OP_LT: case OP_LE:
838     case OP_LTI: case OP_LEI:
839     case OP_GTI: case OP_GEI:
840     case OP_EQ: {  /* note that 'OP_EQI'/'OP_EQK' cannot yield */
841       int res = !l_isfalse(s2v(L->top.p - 1));
842       L->top.p--;
843 #if defined(LUA_COMPAT_LT_LE)
844       if (ci->callstatus & CIST_LEQ) {  /* "<=" using "<" instead? */
845         ci->callstatus ^= CIST_LEQ;  /* clear mark */
846         res = !res;  /* negate result */
847       }
848 #endif
849       lua_assert(GET_OPCODE(*ci->u.l.savedpc) == OP_JMP);
850       if (res != GETARG_k(inst))  /* condition failed? */
851         ci->u.l.savedpc++;  /* skip jump instruction */
852       break;
853     }
854     case OP_CONCAT: {
855       StkId top = L->top.p - 1;  /* top when 'luaT_tryconcatTM' was called */
856       int a = GETARG_A(inst);      /* first element to concatenate */
857       int total = cast_int(top - 1 - (base + a));  /* yet to concatenate */
858       setobjs2s(L, top - 2, top);  /* put TM result in proper position */
859       L->top.p = top - 1;  /* top is one after last element (at top-2) */
860       luaV_concat(L, total);  /* concat them (may yield again) */
861       break;
862     }
863     case OP_CLOSE: {  /* yielded closing variables */
864       ci->u.l.savedpc--;  /* repeat instruction to close other vars. */
865       break;
866     }
867     case OP_RETURN: {  /* yielded closing variables */
868       StkId ra = base + GETARG_A(inst);
869       /* adjust top to signal correct number of returns, in case the
870          return is "up to top" ('isIT') */
871       L->top.p = ra + ci->u2.nres;
872       /* repeat instruction to close other vars. and complete the return */
873       ci->u.l.savedpc--;
874       break;
875     }
876     default: {
877       /* only these other opcodes can yield */
878       lua_assert(op == OP_TFORCALL || op == OP_CALL ||
879            op == OP_TAILCALL || op == OP_SETTABUP || op == OP_SETTABLE ||
880            op == OP_SETI || op == OP_SETFIELD);
881       break;
882     }
883   }
884 }
885 
886 
887 
888 
889 /*
890 ** {==================================================================
891 ** Macros for arithmetic/bitwise/comparison opcodes in 'luaV_execute'
892 ** ===================================================================
893 */
894 
895 #define l_addi(L,a,b)	intop(+, a, b)
896 #define l_subi(L,a,b)	intop(-, a, b)
897 #define l_muli(L,a,b)	intop(*, a, b)
898 #define l_band(a,b)	intop(&, a, b)
899 #define l_bor(a,b)	intop(|, a, b)
900 #define l_bxor(a,b)	intop(^, a, b)
901 
902 #define l_lti(a,b)	(a < b)
903 #define l_lei(a,b)	(a <= b)
904 #define l_gti(a,b)	(a > b)
905 #define l_gei(a,b)	(a >= b)
906 
907 
908 /*
909 ** Arithmetic operations with immediate operands. 'iop' is the integer
910 ** operation, 'fop' is the float operation.
911 */
912 #define op_arithI(L,iop,fop) {  \
913   StkId ra = RA(i); \
914   TValue *v1 = vRB(i);  \
915   int imm = GETARG_sC(i);  \
916   if (ttisinteger(v1)) {  \
917     lua_Integer iv1 = ivalue(v1);  \
918     pc++; setivalue(s2v(ra), iop(L, iv1, imm));  \
919   }  \
920   else if (ttisfloat(v1)) {  \
921     lua_Number nb = fltvalue(v1);  \
922     lua_Number fimm = cast_num(imm);  \
923     pc++; setfltvalue(s2v(ra), fop(L, nb, fimm)); \
924   }}
925 
926 
927 /*
928 ** Auxiliary function for arithmetic operations over floats and others
929 ** with two register operands.
930 */
931 #define op_arithf_aux(L,v1,v2,fop) {  \
932   lua_Number n1; lua_Number n2;  \
933   if (tonumberns(v1, n1) && tonumberns(v2, n2)) {  \
934     pc++; setfltvalue(s2v(ra), fop(L, n1, n2));  \
935   }}
936 
937 
938 /*
939 ** Arithmetic operations over floats and others with register operands.
940 */
941 #define op_arithf(L,fop) {  \
942   StkId ra = RA(i); \
943   TValue *v1 = vRB(i);  \
944   TValue *v2 = vRC(i);  \
945   op_arithf_aux(L, v1, v2, fop); }
946 
947 
948 /*
949 ** Arithmetic operations with K operands for floats.
950 */
951 #define op_arithfK(L,fop) {  \
952   StkId ra = RA(i); \
953   TValue *v1 = vRB(i);  \
954   TValue *v2 = KC(i); lua_assert(ttisnumber(v2));  \
955   op_arithf_aux(L, v1, v2, fop); }
956 
957 
958 /*
959 ** Arithmetic operations over integers and floats.
960 */
961 #define op_arith_aux(L,v1,v2,iop,fop) {  \
962   StkId ra = RA(i); \
963   if (ttisinteger(v1) && ttisinteger(v2)) {  \
964     lua_Integer i1 = ivalue(v1); lua_Integer i2 = ivalue(v2);  \
965     pc++; setivalue(s2v(ra), iop(L, i1, i2));  \
966   }  \
967   else op_arithf_aux(L, v1, v2, fop); }
968 
969 
970 /*
971 ** Arithmetic operations with register operands.
972 */
973 #define op_arith(L,iop,fop) {  \
974   TValue *v1 = vRB(i);  \
975   TValue *v2 = vRC(i);  \
976   op_arith_aux(L, v1, v2, iop, fop); }
977 
978 
979 /*
980 ** Arithmetic operations with K operands.
981 */
982 #define op_arithK(L,iop,fop) {  \
983   TValue *v1 = vRB(i);  \
984   TValue *v2 = KC(i); lua_assert(ttisnumber(v2));  \
985   op_arith_aux(L, v1, v2, iop, fop); }
986 
987 
988 /*
989 ** Bitwise operations with constant operand.
990 */
991 #define op_bitwiseK(L,op) {  \
992   StkId ra = RA(i); \
993   TValue *v1 = vRB(i);  \
994   TValue *v2 = KC(i);  \
995   lua_Integer i1;  \
996   lua_Integer i2 = ivalue(v2);  \
997   if (tointegerns(v1, &i1)) {  \
998     pc++; setivalue(s2v(ra), op(i1, i2));  \
999   }}
1000 
1001 
1002 /*
1003 ** Bitwise operations with register operands.
1004 */
1005 #define op_bitwise(L,op) {  \
1006   StkId ra = RA(i); \
1007   TValue *v1 = vRB(i);  \
1008   TValue *v2 = vRC(i);  \
1009   lua_Integer i1; lua_Integer i2;  \
1010   if (tointegerns(v1, &i1) && tointegerns(v2, &i2)) {  \
1011     pc++; setivalue(s2v(ra), op(i1, i2));  \
1012   }}
1013 
1014 
1015 /*
1016 ** Order operations with register operands. 'opn' actually works
1017 ** for all numbers, but the fast track improves performance for
1018 ** integers.
1019 */
1020 #define op_order(L,opi,opn,other) {  \
1021   StkId ra = RA(i); \
1022   int cond;  \
1023   TValue *rb = vRB(i);  \
1024   if (ttisinteger(s2v(ra)) && ttisinteger(rb)) {  \
1025     lua_Integer ia = ivalue(s2v(ra));  \
1026     lua_Integer ib = ivalue(rb);  \
1027     cond = opi(ia, ib);  \
1028   }  \
1029   else if (ttisnumber(s2v(ra)) && ttisnumber(rb))  \
1030     cond = opn(s2v(ra), rb);  \
1031   else  \
1032     Protect(cond = other(L, s2v(ra), rb));  \
1033   docondjump(); }
1034 
1035 
1036 /*
1037 ** Order operations with immediate operand. (Immediate operand is
1038 ** always small enough to have an exact representation as a float.)
1039 */
1040 #define op_orderI(L,opi,opf,inv,tm) {  \
1041   StkId ra = RA(i); \
1042   int cond;  \
1043   int im = GETARG_sB(i);  \
1044   if (ttisinteger(s2v(ra)))  \
1045     cond = opi(ivalue(s2v(ra)), im);  \
1046   else if (ttisfloat(s2v(ra))) {  \
1047     lua_Number fa = fltvalue(s2v(ra));  \
1048     lua_Number fim = cast_num(im);  \
1049     cond = opf(fa, fim);  \
1050   }  \
1051   else {  \
1052     int isf = GETARG_C(i);  \
1053     Protect(cond = luaT_callorderiTM(L, s2v(ra), im, inv, isf, tm));  \
1054   }  \
1055   docondjump(); }
1056 
1057 /* }================================================================== */
1058 
1059 
1060 /*
1061 ** {==================================================================
1062 ** Function 'luaV_execute': main interpreter loop
1063 ** ===================================================================
1064 */
1065 
1066 /*
1067 ** some macros for common tasks in 'luaV_execute'
1068 */
1069 
1070 
1071 #define RA(i)	(base+GETARG_A(i))
1072 #define RB(i)	(base+GETARG_B(i))
1073 #define vRB(i)	s2v(RB(i))
1074 #define KB(i)	(k+GETARG_B(i))
1075 #define RC(i)	(base+GETARG_C(i))
1076 #define vRC(i)	s2v(RC(i))
1077 #define KC(i)	(k+GETARG_C(i))
1078 #define RKC(i)	((TESTARG_k(i)) ? k + GETARG_C(i) : s2v(base + GETARG_C(i)))
1079 
1080 
1081 
1082 #define updatetrap(ci)  (trap = ci->u.l.trap)
1083 
1084 #define updatebase(ci)	(base = ci->func.p + 1)
1085 
1086 
1087 #define updatestack(ci)  \
1088 	{ if (l_unlikely(trap)) { updatebase(ci); ra = RA(i); } }
1089 
1090 
1091 /*
1092 ** Execute a jump instruction. The 'updatetrap' allows signals to stop
1093 ** tight loops. (Without it, the local copy of 'trap' could never change.)
1094 */
1095 #define dojump(ci,i,e)	{ pc += GETARG_sJ(i) + e; updatetrap(ci); }
1096 
1097 
1098 /* for test instructions, execute the jump instruction that follows it */
1099 #define donextjump(ci)	{ Instruction ni = *pc; dojump(ci, ni, 1); }
1100 
1101 /*
1102 ** do a conditional jump: skip next instruction if 'cond' is not what
1103 ** was expected (parameter 'k'), else do next instruction, which must
1104 ** be a jump.
1105 */
1106 #define docondjump()	if (cond != GETARG_k(i)) pc++; else donextjump(ci);
1107 
1108 
1109 /*
1110 ** Correct global 'pc'.
1111 */
1112 #define savepc(L)	(ci->u.l.savedpc = pc)
1113 
1114 
1115 /*
1116 ** Whenever code can raise errors, the global 'pc' and the global
1117 ** 'top' must be correct to report occasional errors.
1118 */
1119 #define savestate(L,ci)		(savepc(L), L->top.p = ci->top.p)
1120 
1121 
1122 /*
1123 ** Protect code that, in general, can raise errors, reallocate the
1124 ** stack, and change the hooks.
1125 */
1126 #define Protect(exp)  (savestate(L,ci), (exp), updatetrap(ci))
1127 
1128 /* special version that does not change the top */
1129 #define ProtectNT(exp)  (savepc(L), (exp), updatetrap(ci))
1130 
1131 /*
1132 ** Protect code that can only raise errors. (That is, it cannot change
1133 ** the stack or hooks.)
1134 */
1135 #define halfProtect(exp)  (savestate(L,ci), (exp))
1136 
1137 /* 'c' is the limit of live values in the stack */
1138 #define checkGC(L,c)  \
1139 	{ luaC_condGC(L, (savepc(L), L->top.p = (c)), \
1140                          updatetrap(ci)); \
1141            luai_threadyield(L); }
1142 
1143 
1144 /* fetch an instruction and prepare its execution */
1145 #define vmfetch()	{ \
1146   if (l_unlikely(trap)) {  /* stack reallocation or hooks? */ \
1147     trap = luaG_traceexec(L, pc);  /* handle hooks */ \
1148     updatebase(ci);  /* correct stack */ \
1149   } \
1150   i = *(pc++); \
1151 }
1152 
1153 #define vmdispatch(o)	switch(o)
1154 #define vmcase(l)	case l:
1155 #define vmbreak		break
1156 
1157 
luaV_execute(lua_State * L,CallInfo * ci)1158 void luaV_execute (lua_State *L, CallInfo *ci) {
1159   LClosure *cl;
1160   TValue *k;
1161   StkId base;
1162   const Instruction *pc;
1163   int trap;
1164 #if LUA_USE_JUMPTABLE
1165 #include "ljumptab.h"
1166 #endif
1167  startfunc:
1168   trap = L->hookmask;
1169  returning:  /* trap already set */
1170   cl = ci_func(ci);
1171   k = cl->p->k;
1172   pc = ci->u.l.savedpc;
1173   if (l_unlikely(trap))
1174     trap = luaG_tracecall(L);
1175   base = ci->func.p + 1;
1176   /* main loop of interpreter */
1177   for (;;) {
1178     Instruction i;  /* instruction being executed */
1179     vmfetch();
1180     #if 0
1181       /* low-level line tracing for debugging Lua */
1182       printf("line: %d\n", luaG_getfuncline(cl->p, pcRel(pc, cl->p)));
1183     #endif
1184     lua_assert(base == ci->func.p + 1);
1185     lua_assert(base <= L->top.p && L->top.p <= L->stack_last.p);
1186     /* invalidate top for instructions not expecting it */
1187     lua_assert(isIT(i) || (cast_void(L->top.p = base), 1));
1188     vmdispatch (GET_OPCODE(i)) {
1189       vmcase(OP_MOVE) {
1190         StkId ra = RA(i);
1191         setobjs2s(L, ra, RB(i));
1192         vmbreak;
1193       }
1194       vmcase(OP_LOADI) {
1195         StkId ra = RA(i);
1196         lua_Integer b = GETARG_sBx(i);
1197         setivalue(s2v(ra), b);
1198         vmbreak;
1199       }
1200       vmcase(OP_LOADF) {
1201         StkId ra = RA(i);
1202         int b = GETARG_sBx(i);
1203         setfltvalue(s2v(ra), cast_num(b));
1204         vmbreak;
1205       }
1206       vmcase(OP_LOADK) {
1207         StkId ra = RA(i);
1208         TValue *rb = k + GETARG_Bx(i);
1209         setobj2s(L, ra, rb);
1210         vmbreak;
1211       }
1212       vmcase(OP_LOADKX) {
1213         StkId ra = RA(i);
1214         TValue *rb;
1215         rb = k + GETARG_Ax(*pc); pc++;
1216         setobj2s(L, ra, rb);
1217         vmbreak;
1218       }
1219       vmcase(OP_LOADFALSE) {
1220         StkId ra = RA(i);
1221         setbfvalue(s2v(ra));
1222         vmbreak;
1223       }
1224       vmcase(OP_LFALSESKIP) {
1225         StkId ra = RA(i);
1226         setbfvalue(s2v(ra));
1227         pc++;  /* skip next instruction */
1228         vmbreak;
1229       }
1230       vmcase(OP_LOADTRUE) {
1231         StkId ra = RA(i);
1232         setbtvalue(s2v(ra));
1233         vmbreak;
1234       }
1235       vmcase(OP_LOADNIL) {
1236         StkId ra = RA(i);
1237         int b = GETARG_B(i);
1238         do {
1239           setnilvalue(s2v(ra++));
1240         } while (b--);
1241         vmbreak;
1242       }
1243       vmcase(OP_GETUPVAL) {
1244         StkId ra = RA(i);
1245         int b = GETARG_B(i);
1246         setobj2s(L, ra, cl->upvals[b]->v.p);
1247         vmbreak;
1248       }
1249       vmcase(OP_SETUPVAL) {
1250         StkId ra = RA(i);
1251         UpVal *uv = cl->upvals[GETARG_B(i)];
1252         setobj(L, uv->v.p, s2v(ra));
1253         luaC_barrier(L, uv, s2v(ra));
1254         vmbreak;
1255       }
1256       vmcase(OP_GETTABUP) {
1257         StkId ra = RA(i);
1258         const TValue *slot;
1259         TValue *upval = cl->upvals[GETARG_B(i)]->v.p;
1260         TValue *rc = KC(i);
1261         TString *key = tsvalue(rc);  /* key must be a short string */
1262         if (luaV_fastget(L, upval, key, slot, luaH_getshortstr)) {
1263           setobj2s(L, ra, slot);
1264         }
1265         else
1266           Protect(luaV_finishget(L, upval, rc, ra, slot));
1267         vmbreak;
1268       }
1269       vmcase(OP_GETTABLE) {
1270         StkId ra = RA(i);
1271         const TValue *slot;
1272         TValue *rb = vRB(i);
1273         TValue *rc = vRC(i);
1274         lua_Unsigned n;
1275         if (ttisinteger(rc)  /* fast track for integers? */
1276             ? (cast_void(n = ivalue(rc)), luaV_fastgeti(L, rb, n, slot))
1277             : luaV_fastget(L, rb, rc, slot, luaH_get)) {
1278           setobj2s(L, ra, slot);
1279         }
1280         else
1281           Protect(luaV_finishget(L, rb, rc, ra, slot));
1282         vmbreak;
1283       }
1284       vmcase(OP_GETI) {
1285         StkId ra = RA(i);
1286         const TValue *slot;
1287         TValue *rb = vRB(i);
1288         int c = GETARG_C(i);
1289         if (luaV_fastgeti(L, rb, c, slot)) {
1290           setobj2s(L, ra, slot);
1291         }
1292         else {
1293           TValue key;
1294           setivalue(&key, c);
1295           Protect(luaV_finishget(L, rb, &key, ra, slot));
1296         }
1297         vmbreak;
1298       }
1299       vmcase(OP_GETFIELD) {
1300         StkId ra = RA(i);
1301         const TValue *slot;
1302         TValue *rb = vRB(i);
1303         TValue *rc = KC(i);
1304         TString *key = tsvalue(rc);  /* key must be a short string */
1305         if (luaV_fastget(L, rb, key, slot, luaH_getshortstr)) {
1306           setobj2s(L, ra, slot);
1307         }
1308         else
1309           Protect(luaV_finishget(L, rb, rc, ra, slot));
1310         vmbreak;
1311       }
1312       vmcase(OP_SETTABUP) {
1313         const TValue *slot;
1314         TValue *upval = cl->upvals[GETARG_A(i)]->v.p;
1315         TValue *rb = KB(i);
1316         TValue *rc = RKC(i);
1317         TString *key = tsvalue(rb);  /* key must be a short string */
1318         if (luaV_fastget(L, upval, key, slot, luaH_getshortstr)) {
1319           luaV_finishfastset(L, upval, slot, rc);
1320         }
1321         else
1322           Protect(luaV_finishset(L, upval, rb, rc, slot));
1323         vmbreak;
1324       }
1325       vmcase(OP_SETTABLE) {
1326         StkId ra = RA(i);
1327         const TValue *slot;
1328         TValue *rb = vRB(i);  /* key (table is in 'ra') */
1329         TValue *rc = RKC(i);  /* value */
1330         lua_Unsigned n;
1331         if (ttisinteger(rb)  /* fast track for integers? */
1332             ? (cast_void(n = ivalue(rb)), luaV_fastgeti(L, s2v(ra), n, slot))
1333             : luaV_fastget(L, s2v(ra), rb, slot, luaH_get)) {
1334           luaV_finishfastset(L, s2v(ra), slot, rc);
1335         }
1336         else
1337           Protect(luaV_finishset(L, s2v(ra), rb, rc, slot));
1338         vmbreak;
1339       }
1340       vmcase(OP_SETI) {
1341         StkId ra = RA(i);
1342         const TValue *slot;
1343         int c = GETARG_B(i);
1344         TValue *rc = RKC(i);
1345         if (luaV_fastgeti(L, s2v(ra), c, slot)) {
1346           luaV_finishfastset(L, s2v(ra), slot, rc);
1347         }
1348         else {
1349           TValue key;
1350           setivalue(&key, c);
1351           Protect(luaV_finishset(L, s2v(ra), &key, rc, slot));
1352         }
1353         vmbreak;
1354       }
1355       vmcase(OP_SETFIELD) {
1356         StkId ra = RA(i);
1357         const TValue *slot;
1358         TValue *rb = KB(i);
1359         TValue *rc = RKC(i);
1360         TString *key = tsvalue(rb);  /* key must be a short string */
1361         if (luaV_fastget(L, s2v(ra), key, slot, luaH_getshortstr)) {
1362           luaV_finishfastset(L, s2v(ra), slot, rc);
1363         }
1364         else
1365           Protect(luaV_finishset(L, s2v(ra), rb, rc, slot));
1366         vmbreak;
1367       }
1368       vmcase(OP_NEWTABLE) {
1369         StkId ra = RA(i);
1370         int b = GETARG_B(i);  /* log2(hash size) + 1 */
1371         int c = GETARG_C(i);  /* array size */
1372         Table *t;
1373         if (b > 0)
1374           b = 1 << (b - 1);  /* size is 2^(b - 1) */
1375         lua_assert((!TESTARG_k(i)) == (GETARG_Ax(*pc) == 0));
1376         if (TESTARG_k(i))  /* non-zero extra argument? */
1377           c += GETARG_Ax(*pc) * (MAXARG_C + 1);  /* add it to size */
1378         pc++;  /* skip extra argument */
1379         L->top.p = ra + 1;  /* correct top in case of emergency GC */
1380         t = luaH_new(L);  /* memory allocation */
1381         sethvalue2s(L, ra, t);
1382         if (b != 0 || c != 0)
1383           luaH_resize(L, t, c, b);  /* idem */
1384         checkGC(L, ra + 1);
1385         vmbreak;
1386       }
1387       vmcase(OP_SELF) {
1388         StkId ra = RA(i);
1389         const TValue *slot;
1390         TValue *rb = vRB(i);
1391         TValue *rc = RKC(i);
1392         TString *key = tsvalue(rc);  /* key must be a string */
1393         setobj2s(L, ra + 1, rb);
1394         if (luaV_fastget(L, rb, key, slot, luaH_getstr)) {
1395           setobj2s(L, ra, slot);
1396         }
1397         else
1398           Protect(luaV_finishget(L, rb, rc, ra, slot));
1399         vmbreak;
1400       }
1401       vmcase(OP_ADDI) {
1402         op_arithI(L, l_addi, luai_numadd);
1403         vmbreak;
1404       }
1405       vmcase(OP_ADDK) {
1406         op_arithK(L, l_addi, luai_numadd);
1407         vmbreak;
1408       }
1409       vmcase(OP_SUBK) {
1410         op_arithK(L, l_subi, luai_numsub);
1411         vmbreak;
1412       }
1413       vmcase(OP_MULK) {
1414         op_arithK(L, l_muli, luai_nummul);
1415         vmbreak;
1416       }
1417       vmcase(OP_MODK) {
1418         savestate(L, ci);  /* in case of division by 0 */
1419         op_arithK(L, luaV_mod, luaV_modf);
1420         vmbreak;
1421       }
1422       vmcase(OP_POWK) {
1423         op_arithfK(L, luai_numpow);
1424         vmbreak;
1425       }
1426       vmcase(OP_DIVK) {
1427         op_arithfK(L, luai_numdiv);
1428         vmbreak;
1429       }
1430       vmcase(OP_IDIVK) {
1431         savestate(L, ci);  /* in case of division by 0 */
1432         op_arithK(L, luaV_idiv, luai_numidiv);
1433         vmbreak;
1434       }
1435       vmcase(OP_BANDK) {
1436         op_bitwiseK(L, l_band);
1437         vmbreak;
1438       }
1439       vmcase(OP_BORK) {
1440         op_bitwiseK(L, l_bor);
1441         vmbreak;
1442       }
1443       vmcase(OP_BXORK) {
1444         op_bitwiseK(L, l_bxor);
1445         vmbreak;
1446       }
1447       vmcase(OP_SHRI) {
1448         StkId ra = RA(i);
1449         TValue *rb = vRB(i);
1450         int ic = GETARG_sC(i);
1451         lua_Integer ib;
1452         if (tointegerns(rb, &ib)) {
1453           pc++; setivalue(s2v(ra), luaV_shiftl(ib, -ic));
1454         }
1455         vmbreak;
1456       }
1457       vmcase(OP_SHLI) {
1458         StkId ra = RA(i);
1459         TValue *rb = vRB(i);
1460         int ic = GETARG_sC(i);
1461         lua_Integer ib;
1462         if (tointegerns(rb, &ib)) {
1463           pc++; setivalue(s2v(ra), luaV_shiftl(ic, ib));
1464         }
1465         vmbreak;
1466       }
1467       vmcase(OP_ADD) {
1468         op_arith(L, l_addi, luai_numadd);
1469         vmbreak;
1470       }
1471       vmcase(OP_SUB) {
1472         op_arith(L, l_subi, luai_numsub);
1473         vmbreak;
1474       }
1475       vmcase(OP_MUL) {
1476         op_arith(L, l_muli, luai_nummul);
1477         vmbreak;
1478       }
1479       vmcase(OP_MOD) {
1480         savestate(L, ci);  /* in case of division by 0 */
1481         op_arith(L, luaV_mod, luaV_modf);
1482         vmbreak;
1483       }
1484       vmcase(OP_POW) {
1485         op_arithf(L, luai_numpow);
1486         vmbreak;
1487       }
1488       vmcase(OP_DIV) {  /* float division (always with floats) */
1489         op_arithf(L, luai_numdiv);
1490         vmbreak;
1491       }
1492       vmcase(OP_IDIV) {  /* floor division */
1493         savestate(L, ci);  /* in case of division by 0 */
1494         op_arith(L, luaV_idiv, luai_numidiv);
1495         vmbreak;
1496       }
1497       vmcase(OP_BAND) {
1498         op_bitwise(L, l_band);
1499         vmbreak;
1500       }
1501       vmcase(OP_BOR) {
1502         op_bitwise(L, l_bor);
1503         vmbreak;
1504       }
1505       vmcase(OP_BXOR) {
1506         op_bitwise(L, l_bxor);
1507         vmbreak;
1508       }
1509       vmcase(OP_SHR) {
1510         op_bitwise(L, luaV_shiftr);
1511         vmbreak;
1512       }
1513       vmcase(OP_SHL) {
1514         op_bitwise(L, luaV_shiftl);
1515         vmbreak;
1516       }
1517       vmcase(OP_MMBIN) {
1518         StkId ra = RA(i);
1519         Instruction pi = *(pc - 2);  /* original arith. expression */
1520         TValue *rb = vRB(i);
1521         TMS tm = (TMS)GETARG_C(i);
1522         StkId result = RA(pi);
1523         lua_assert(OP_ADD <= GET_OPCODE(pi) && GET_OPCODE(pi) <= OP_SHR);
1524         Protect(luaT_trybinTM(L, s2v(ra), rb, result, tm));
1525         vmbreak;
1526       }
1527       vmcase(OP_MMBINI) {
1528         StkId ra = RA(i);
1529         Instruction pi = *(pc - 2);  /* original arith. expression */
1530         int imm = GETARG_sB(i);
1531         TMS tm = (TMS)GETARG_C(i);
1532         int flip = GETARG_k(i);
1533         StkId result = RA(pi);
1534         Protect(luaT_trybiniTM(L, s2v(ra), imm, flip, result, tm));
1535         vmbreak;
1536       }
1537       vmcase(OP_MMBINK) {
1538         StkId ra = RA(i);
1539         Instruction pi = *(pc - 2);  /* original arith. expression */
1540         TValue *imm = KB(i);
1541         TMS tm = (TMS)GETARG_C(i);
1542         int flip = GETARG_k(i);
1543         StkId result = RA(pi);
1544         Protect(luaT_trybinassocTM(L, s2v(ra), imm, flip, result, tm));
1545         vmbreak;
1546       }
1547       vmcase(OP_UNM) {
1548         StkId ra = RA(i);
1549         TValue *rb = vRB(i);
1550         lua_Number nb;
1551         if (ttisinteger(rb)) {
1552           lua_Integer ib = ivalue(rb);
1553           setivalue(s2v(ra), intop(-, 0, ib));
1554         }
1555         else if (tonumberns(rb, nb)) {
1556           setfltvalue(s2v(ra), luai_numunm(L, nb));
1557         }
1558         else
1559           Protect(luaT_trybinTM(L, rb, rb, ra, TM_UNM));
1560         vmbreak;
1561       }
1562       vmcase(OP_BNOT) {
1563         StkId ra = RA(i);
1564         TValue *rb = vRB(i);
1565         lua_Integer ib;
1566         if (tointegerns(rb, &ib)) {
1567           setivalue(s2v(ra), intop(^, ~l_castS2U(0), ib));
1568         }
1569         else
1570           Protect(luaT_trybinTM(L, rb, rb, ra, TM_BNOT));
1571         vmbreak;
1572       }
1573       vmcase(OP_NOT) {
1574         StkId ra = RA(i);
1575         TValue *rb = vRB(i);
1576         if (l_isfalse(rb))
1577           setbtvalue(s2v(ra));
1578         else
1579           setbfvalue(s2v(ra));
1580         vmbreak;
1581       }
1582       vmcase(OP_LEN) {
1583         StkId ra = RA(i);
1584         Protect(luaV_objlen(L, ra, vRB(i)));
1585         vmbreak;
1586       }
1587       vmcase(OP_CONCAT) {
1588         StkId ra = RA(i);
1589         int n = GETARG_B(i);  /* number of elements to concatenate */
1590         L->top.p = ra + n;  /* mark the end of concat operands */
1591         ProtectNT(luaV_concat(L, n));
1592         checkGC(L, L->top.p); /* 'luaV_concat' ensures correct top */
1593         vmbreak;
1594       }
1595       vmcase(OP_CLOSE) {
1596         StkId ra = RA(i);
1597         Protect(luaF_close(L, ra, LUA_OK, 1));
1598         vmbreak;
1599       }
1600       vmcase(OP_TBC) {
1601         StkId ra = RA(i);
1602         /* create new to-be-closed upvalue */
1603         halfProtect(luaF_newtbcupval(L, ra));
1604         vmbreak;
1605       }
1606       vmcase(OP_JMP) {
1607         dojump(ci, i, 0);
1608         vmbreak;
1609       }
1610       vmcase(OP_EQ) {
1611         StkId ra = RA(i);
1612         int cond;
1613         TValue *rb = vRB(i);
1614         Protect(cond = luaV_equalobj(L, s2v(ra), rb));
1615         docondjump();
1616         vmbreak;
1617       }
1618       vmcase(OP_LT) {
1619         op_order(L, l_lti, LTnum, lessthanothers);
1620         vmbreak;
1621       }
1622       vmcase(OP_LE) {
1623         op_order(L, l_lei, LEnum, lessequalothers);
1624         vmbreak;
1625       }
1626       vmcase(OP_EQK) {
1627         StkId ra = RA(i);
1628         TValue *rb = KB(i);
1629         /* basic types do not use '__eq'; we can use raw equality */
1630         int cond = luaV_rawequalobj(s2v(ra), rb);
1631         docondjump();
1632         vmbreak;
1633       }
1634       vmcase(OP_EQI) {
1635         StkId ra = RA(i);
1636         int cond;
1637         int im = GETARG_sB(i);
1638         if (ttisinteger(s2v(ra)))
1639           cond = (ivalue(s2v(ra)) == im);
1640         else if (ttisfloat(s2v(ra)))
1641           cond = luai_numeq(fltvalue(s2v(ra)), cast_num(im));
1642         else
1643           cond = 0;  /* other types cannot be equal to a number */
1644         docondjump();
1645         vmbreak;
1646       }
1647       vmcase(OP_LTI) {
1648         op_orderI(L, l_lti, luai_numlt, 0, TM_LT);
1649         vmbreak;
1650       }
1651       vmcase(OP_LEI) {
1652         op_orderI(L, l_lei, luai_numle, 0, TM_LE);
1653         vmbreak;
1654       }
1655       vmcase(OP_GTI) {
1656         op_orderI(L, l_gti, luai_numgt, 1, TM_LT);
1657         vmbreak;
1658       }
1659       vmcase(OP_GEI) {
1660         op_orderI(L, l_gei, luai_numge, 1, TM_LE);
1661         vmbreak;
1662       }
1663       vmcase(OP_TEST) {
1664         StkId ra = RA(i);
1665         int cond = !l_isfalse(s2v(ra));
1666         docondjump();
1667         vmbreak;
1668       }
1669       vmcase(OP_TESTSET) {
1670         StkId ra = RA(i);
1671         TValue *rb = vRB(i);
1672         if (l_isfalse(rb) == GETARG_k(i))
1673           pc++;
1674         else {
1675           setobj2s(L, ra, rb);
1676           donextjump(ci);
1677         }
1678         vmbreak;
1679       }
1680       vmcase(OP_CALL) {
1681         StkId ra = RA(i);
1682         CallInfo *newci;
1683         int b = GETARG_B(i);
1684         int nresults = GETARG_C(i) - 1;
1685         if (b != 0)  /* fixed number of arguments? */
1686           L->top.p = ra + b;  /* top signals number of arguments */
1687         /* else previous instruction set top */
1688         savepc(L);  /* in case of errors */
1689         if ((newci = luaD_precall(L, ra, nresults)) == NULL)
1690           updatetrap(ci);  /* C call; nothing else to be done */
1691         else {  /* Lua call: run function in this same C frame */
1692           ci = newci;
1693           goto startfunc;
1694         }
1695         vmbreak;
1696       }
1697       vmcase(OP_TAILCALL) {
1698         StkId ra = RA(i);
1699         int b = GETARG_B(i);  /* number of arguments + 1 (function) */
1700         int n;  /* number of results when calling a C function */
1701         int nparams1 = GETARG_C(i);
1702         /* delta is virtual 'func' - real 'func' (vararg functions) */
1703         int delta = (nparams1) ? ci->u.l.nextraargs + nparams1 : 0;
1704         if (b != 0)
1705           L->top.p = ra + b;
1706         else  /* previous instruction set top */
1707           b = cast_int(L->top.p - ra);
1708         savepc(ci);  /* several calls here can raise errors */
1709         if (TESTARG_k(i)) {
1710           luaF_closeupval(L, base);  /* close upvalues from current call */
1711           lua_assert(L->tbclist.p < base);  /* no pending tbc variables */
1712           lua_assert(base == ci->func.p + 1);
1713         }
1714         if ((n = luaD_pretailcall(L, ci, ra, b, delta)) < 0)  /* Lua function? */
1715           goto startfunc;  /* execute the callee */
1716         else {  /* C function? */
1717           ci->func.p -= delta;  /* restore 'func' (if vararg) */
1718           luaD_poscall(L, ci, n);  /* finish caller */
1719           updatetrap(ci);  /* 'luaD_poscall' can change hooks */
1720           goto ret;  /* caller returns after the tail call */
1721         }
1722       }
1723       vmcase(OP_RETURN) {
1724         StkId ra = RA(i);
1725         int n = GETARG_B(i) - 1;  /* number of results */
1726         int nparams1 = GETARG_C(i);
1727         if (n < 0)  /* not fixed? */
1728           n = cast_int(L->top.p - ra);  /* get what is available */
1729         savepc(ci);
1730         if (TESTARG_k(i)) {  /* may there be open upvalues? */
1731           ci->u2.nres = n;  /* save number of returns */
1732           if (L->top.p < ci->top.p)
1733             L->top.p = ci->top.p;
1734           luaF_close(L, base, CLOSEKTOP, 1);
1735           updatetrap(ci);
1736           updatestack(ci);
1737         }
1738         if (nparams1)  /* vararg function? */
1739           ci->func.p -= ci->u.l.nextraargs + nparams1;
1740         L->top.p = ra + n;  /* set call for 'luaD_poscall' */
1741         luaD_poscall(L, ci, n);
1742         updatetrap(ci);  /* 'luaD_poscall' can change hooks */
1743         goto ret;
1744       }
1745       vmcase(OP_RETURN0) {
1746         if (l_unlikely(L->hookmask)) {
1747           StkId ra = RA(i);
1748           L->top.p = ra;
1749           savepc(ci);
1750           luaD_poscall(L, ci, 0);  /* no hurry... */
1751           trap = 1;
1752         }
1753         else {  /* do the 'poscall' here */
1754           int nres;
1755           L->ci = ci->previous;  /* back to caller */
1756           L->top.p = base - 1;
1757           for (nres = ci->nresults; l_unlikely(nres > 0); nres--)
1758             setnilvalue(s2v(L->top.p++));  /* all results are nil */
1759         }
1760         goto ret;
1761       }
1762       vmcase(OP_RETURN1) {
1763         if (l_unlikely(L->hookmask)) {
1764           StkId ra = RA(i);
1765           L->top.p = ra + 1;
1766           savepc(ci);
1767           luaD_poscall(L, ci, 1);  /* no hurry... */
1768           trap = 1;
1769         }
1770         else {  /* do the 'poscall' here */
1771           int nres = ci->nresults;
1772           L->ci = ci->previous;  /* back to caller */
1773           if (nres == 0)
1774             L->top.p = base - 1;  /* asked for no results */
1775           else {
1776             StkId ra = RA(i);
1777             setobjs2s(L, base - 1, ra);  /* at least this result */
1778             L->top.p = base;
1779             for (; l_unlikely(nres > 1); nres--)
1780               setnilvalue(s2v(L->top.p++));  /* complete missing results */
1781           }
1782         }
1783        ret:  /* return from a Lua function */
1784         if (ci->callstatus & CIST_FRESH)
1785           return;  /* end this frame */
1786         else {
1787           ci = ci->previous;
1788           goto returning;  /* continue running caller in this frame */
1789         }
1790       }
1791       vmcase(OP_FORLOOP) {
1792         StkId ra = RA(i);
1793         if (ttisinteger(s2v(ra + 2))) {  /* integer loop? */
1794           lua_Unsigned count = l_castS2U(ivalue(s2v(ra + 1)));
1795           if (count > 0) {  /* still more iterations? */
1796             lua_Integer step = ivalue(s2v(ra + 2));
1797             lua_Integer idx = ivalue(s2v(ra));  /* internal index */
1798             chgivalue(s2v(ra + 1), count - 1);  /* update counter */
1799             idx = intop(+, idx, step);  /* add step to index */
1800             chgivalue(s2v(ra), idx);  /* update internal index */
1801             setivalue(s2v(ra + 3), idx);  /* and control variable */
1802             pc -= GETARG_Bx(i);  /* jump back */
1803           }
1804         }
1805         else if (floatforloop(ra))  /* float loop */
1806           pc -= GETARG_Bx(i);  /* jump back */
1807         updatetrap(ci);  /* allows a signal to break the loop */
1808         vmbreak;
1809       }
1810       vmcase(OP_FORPREP) {
1811         StkId ra = RA(i);
1812         savestate(L, ci);  /* in case of errors */
1813         if (forprep(L, ra))
1814           pc += GETARG_Bx(i) + 1;  /* skip the loop */
1815         vmbreak;
1816       }
1817       vmcase(OP_TFORPREP) {
1818        StkId ra = RA(i);
1819         /* create to-be-closed upvalue (if needed) */
1820         halfProtect(luaF_newtbcupval(L, ra + 3));
1821         pc += GETARG_Bx(i);
1822         i = *(pc++);  /* go to next instruction */
1823         lua_assert(GET_OPCODE(i) == OP_TFORCALL && ra == RA(i));
1824         goto l_tforcall;
1825       }
1826       vmcase(OP_TFORCALL) {
1827        l_tforcall: {
1828         StkId ra = RA(i);
1829         /* 'ra' has the iterator function, 'ra + 1' has the state,
1830            'ra + 2' has the control variable, and 'ra + 3' has the
1831            to-be-closed variable. The call will use the stack after
1832            these values (starting at 'ra + 4')
1833         */
1834         /* push function, state, and control variable */
1835         memcpy(ra + 4, ra, 3 * sizeof(*ra));
1836         L->top.p = ra + 4 + 3;
1837         ProtectNT(luaD_call(L, ra + 4, GETARG_C(i)));  /* do the call */
1838         updatestack(ci);  /* stack may have changed */
1839         i = *(pc++);  /* go to next instruction */
1840         lua_assert(GET_OPCODE(i) == OP_TFORLOOP && ra == RA(i));
1841         goto l_tforloop;
1842       }}
1843       vmcase(OP_TFORLOOP) {
1844        l_tforloop: {
1845         StkId ra = RA(i);
1846         if (!ttisnil(s2v(ra + 4))) {  /* continue loop? */
1847           setobjs2s(L, ra + 2, ra + 4);  /* save control variable */
1848           pc -= GETARG_Bx(i);  /* jump back */
1849         }
1850         vmbreak;
1851       }}
1852       vmcase(OP_SETLIST) {
1853         StkId ra = RA(i);
1854         int n = GETARG_B(i);
1855         unsigned int last = GETARG_C(i);
1856         Table *h = hvalue(s2v(ra));
1857         if (n == 0)
1858           n = cast_int(L->top.p - ra) - 1;  /* get up to the top */
1859         else
1860           L->top.p = ci->top.p;  /* correct top in case of emergency GC */
1861         last += n;
1862         if (TESTARG_k(i)) {
1863           last += GETARG_Ax(*pc) * (MAXARG_C + 1);
1864           pc++;
1865         }
1866         if (last > luaH_realasize(h))  /* needs more space? */
1867           luaH_resizearray(L, h, last);  /* preallocate it at once */
1868         for (; n > 0; n--) {
1869           TValue *val = s2v(ra + n);
1870           setobj2t(L, &h->array[last - 1], val);
1871           last--;
1872           luaC_barrierback(L, obj2gco(h), val);
1873         }
1874         vmbreak;
1875       }
1876       vmcase(OP_CLOSURE) {
1877         StkId ra = RA(i);
1878         Proto *p = cl->p->p[GETARG_Bx(i)];
1879         halfProtect(pushclosure(L, p, cl->upvals, base, ra));
1880         checkGC(L, ra + 1);
1881         vmbreak;
1882       }
1883       vmcase(OP_VARARG) {
1884         StkId ra = RA(i);
1885         int n = GETARG_C(i) - 1;  /* required results */
1886         Protect(luaT_getvarargs(L, ci, ra, n));
1887         vmbreak;
1888       }
1889       vmcase(OP_VARARGPREP) {
1890         ProtectNT(luaT_adjustvarargs(L, GETARG_A(i), ci, cl->p));
1891         if (l_unlikely(trap)) {  /* previous "Protect" updated trap */
1892           luaD_hookcall(L, ci);
1893           L->oldpc = 1;  /* next opcode will be seen as a "new" line */
1894         }
1895         updatebase(ci);  /* function has new base after adjustment */
1896         vmbreak;
1897       }
1898       vmcase(OP_EXTRAARG) {
1899         lua_assert(0);
1900         vmbreak;
1901       }
1902     }
1903   }
1904 }
1905 
1906 /* }================================================================== */
1907