mudgangster

lvm.cc (44393B)

---

 /*
 ** $Id: lvm.c,v 2.268.1.1 2017/04/19 17:39:34 roberto Exp $
 ** Lua virtual machine
 ** See Copyright Notice in lua.h
 */
 
 #define lvm_c
 #define LUA_CORE
 
 #include "lprefix.h"
 
 #include <float.h>
 #include <limits.h>
 #include <math.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
 #include "lua.h"
 
 #include "ldebug.h"
 #include "ldo.h"
 #include "lfunc.h"
 #include "lgc.h"
 #include "lobject.h"
 #include "lopcodes.h"
 #include "lstate.h"
 #include "lstring.h"
 #include "ltable.h"
 #include "ltm.h"
 #include "lvm.h"
 
 
 /* limit for table tag-method chains (to avoid loops) */
 #define MAXTAGLOOP	2000
 
 
 
 /*
 ** 'l_intfitsf' checks whether a given integer can be converted to a
 ** float without rounding. Used in comparisons. Left undefined if
 ** all integers fit in a float precisely.
 */
 #if !defined(l_intfitsf)
 
 /* number of bits in the mantissa of a float */
 #define NBM		(l_mathlim(MANT_DIG))
 
 /*
 ** Check whether some integers may not fit in a float, that is, whether
 ** (maxinteger >> NBM) > 0 (that implies (1 << NBM) <= maxinteger).
 ** (The shifts are done in parts to avoid shifting by more than the size
 ** of an integer. In a worst case, NBM == 113 for long double and
 ** sizeof(integer) == 32.)
 */
 #if ((((LUA_MAXINTEGER >> (NBM / 4)) >> (NBM / 4)) >> (NBM / 4)) \
 	>> (NBM - (3 * (NBM / 4))))  >  0
 
 #define l_intfitsf(i)  \
   (-((lua_Integer)1 << NBM) <= (i) && (i) <= ((lua_Integer)1 << NBM))
 
 #endif
 
 #endif
 
 
 
 /*
 ** Try to convert a value to a float. The float case is already handled
 ** by the macro 'tonumber'.
 */
 int luaV_tonumber_ (const TValue *obj, lua_Number *n) {
   TValue v;
   if (ttisinteger(obj)) {
     *n = cast_num(ivalue(obj));
     return 1;
   }
   else if (cvt2num(obj) &&  /* string convertible to number? */
             luaO_str2num(svalue(obj), &v) == vslen(obj) + 1) {
     *n = nvalue(&v);  /* convert result of 'luaO_str2num' to a float */
     return 1;
   }
   else
     return 0;  /* conversion failed */
 }
 
 
 /*
 ** try to convert a value to an integer, rounding according to 'mode':
 ** mode == 0: accepts only integral values
 ** mode == 1: takes the floor of the number
 ** mode == 2: takes the ceil of the number
 */
 int luaV_tointeger (const TValue *obj, lua_Integer *p, int mode) {
   TValue v;
  again:
   if (ttisfloat(obj)) {
     lua_Number n = fltvalue(obj);
     lua_Number f = l_floor(n);
     if (n != f) {  /* not an integral value? */
       if (mode == 0) return 0;  /* fails if mode demands integral value */
       else if (mode > 1)  /* needs ceil? */
         f += 1;  /* convert floor to ceil (remember: n != f) */
     }
     return lua_numbertointeger(f, p);
   }
   else if (ttisinteger(obj)) {
     *p = ivalue(obj);
     return 1;
   }
   else if (cvt2num(obj) &&
             luaO_str2num(svalue(obj), &v) == vslen(obj) + 1) {
     obj = &v;
     goto again;  /* convert result from 'luaO_str2num' to an integer */
   }
   return 0;  /* conversion failed */
 }
 
 
 /*
 ** Try to convert a 'for' limit to an integer, preserving the
 ** semantics of the loop.
 ** (The following explanation assumes a non-negative step; it is valid
 ** for negative steps mutatis mutandis.)
 ** If the limit can be converted to an integer, rounding down, that is
 ** it.
 ** Otherwise, check whether the limit can be converted to a number.  If
 ** the number is too large, it is OK to set the limit as LUA_MAXINTEGER,
 ** which means no limit.  If the number is too negative, the loop
 ** should not run, because any initial integer value is larger than the
 ** limit. So, it sets the limit to LUA_MININTEGER. 'stopnow' corrects
 ** the extreme case when the initial value is LUA_MININTEGER, in which
 ** case the LUA_MININTEGER limit would still run the loop once.
 */
 static int forlimit (const TValue *obj, lua_Integer *p, lua_Integer step,
                      int *stopnow) {
   *stopnow = 0;  /* usually, let loops run */
   if (!luaV_tointeger(obj, p, (step < 0 ? 2 : 1))) {  /* not fit in integer? */
     lua_Number n;  /* try to convert to float */
     if (!tonumber(obj, &n)) /* cannot convert to float? */
       return 0;  /* not a number */
     if (luai_numlt(0, n)) {  /* if true, float is larger than max integer */
       *p = LUA_MAXINTEGER;
       if (step < 0) *stopnow = 1;
     }
     else {  /* float is smaller than min integer */
       *p = LUA_MININTEGER;
       if (step >= 0) *stopnow = 1;
     }
   }
   return 1;
 }
 
 
 /*
 ** Finish the table access 'val = t[key]'.
 ** if 'slot' is NULL, 't' is not a table; otherwise, 'slot' points to
 ** t[k] entry (which must be nil).
 */
 void luaV_finishget (lua_State *L, const TValue *t, TValue *key, StkId val,
                       const TValue *slot) {
   int loop;  /* counter to avoid infinite loops */
   const TValue *tm;  /* metamethod */
   for (loop = 0; loop < MAXTAGLOOP; loop++) {
     if (slot == NULL) {  /* 't' is not a table? */
       lua_assert(!ttistable(t));
       tm = luaT_gettmbyobj(L, t, TM_INDEX);
       if (ttisnil(tm))
         luaG_typeerror(L, t, "index");  /* no metamethod */
       /* else will try the metamethod */
     }
     else {  /* 't' is a table */
       lua_assert(ttisnil(slot));
       tm = fasttm(L, hvalue(t)->metatable, TM_INDEX);  /* table's metamethod */
       if (tm == NULL) {  /* no metamethod? */
         setnilvalue(val);  /* result is nil */
         return;
       }
       /* else will try the metamethod */
     }
     if (ttisfunction(tm)) {  /* is metamethod a function? */
       luaT_callTM(L, tm, t, key, val, 1);  /* call it */
       return;
     }
     t = tm;  /* else try to access 'tm[key]' */
     if (luaV_fastget(L,t,key,slot,luaH_get)) {  /* fast track? */
       setobj2s(L, val, slot);  /* done */
       return;
     }
     /* else repeat (tail call 'luaV_finishget') */
   }
   luaG_runerror(L, "'__index' chain too long; possible loop");
 }
 
 
 /*
 ** Finish a table assignment 't[key] = val'.
 ** If 'slot' is NULL, 't' is not a table.  Otherwise, 'slot' points
 ** to the entry 't[key]', or to 'luaO_nilobject' if there is no such
 ** entry.  (The value at 'slot' must be nil, otherwise 'luaV_fastset'
 ** would have done the job.)
 */
 void luaV_finishset (lua_State *L, const TValue *t, TValue *key,
                      StkId val, const TValue *slot) {
   int loop;  /* counter to avoid infinite loops */
   for (loop = 0; loop < MAXTAGLOOP; loop++) {
     const TValue *tm;  /* '__newindex' metamethod */
     if (slot != NULL) {  /* is 't' a table? */
       Table *h = hvalue(t);  /* save 't' table */
       lua_assert(ttisnil(slot));  /* old value must be nil */
       tm = fasttm(L, h->metatable, TM_NEWINDEX);  /* get metamethod */
       if (tm == NULL) {  /* no metamethod? */
         if (slot == luaO_nilobject)  /* no previous entry? */
           slot = luaH_newkey(L, h, key);  /* create one */
         /* no metamethod and (now) there is an entry with given key */
         setobj2t(L, cast(TValue *, slot), val);  /* set its new value */
         invalidateTMcache(h);
         luaC_barrierback(L, h, val);
         return;
       }
       /* else will try the metamethod */
     }
     else {  /* not a table; check metamethod */
       if (ttisnil(tm = luaT_gettmbyobj(L, t, TM_NEWINDEX)))
         luaG_typeerror(L, t, "index");
     }
     /* try the metamethod */
     if (ttisfunction(tm)) {
       luaT_callTM(L, tm, t, key, val, 0);
       return;
     }
     t = tm;  /* else repeat assignment over 'tm' */
     if (luaV_fastset(L, t, key, slot, luaH_get, val))
       return;  /* done */
     /* else loop */
   }
   luaG_runerror(L, "'__newindex' chain too long; possible loop");
 }
 
 
 /*
 ** Compare two strings 'ls' x 'rs', returning an integer smaller-equal-
 ** -larger than zero if 'ls' is smaller-equal-larger than 'rs'.
 ** The code is a little tricky because it allows '\0' in the strings
 ** and it uses 'strcoll' (to respect locales) for each segments
 ** of the strings.
 */
 static int l_strcmp (const TString *ls, const TString *rs) {
   const char *l = getstr(ls);
   size_t ll = tsslen(ls);
   const char *r = getstr(rs);
   size_t lr = tsslen(rs);
   for (;;) {  /* for each segment */
     int temp = strcoll(l, r);
     if (temp != 0)  /* not equal? */
       return temp;  /* done */
     else {  /* strings are equal up to a '\0' */
       size_t len = strlen(l);  /* index of first '\0' in both strings */
       if (len == lr)  /* 'rs' is finished? */
         return (len == ll) ? 0 : 1;  /* check 'ls' */
       else if (len == ll)  /* 'ls' is finished? */
         return -1;  /* 'ls' is smaller than 'rs' ('rs' is not finished) */
       /* both strings longer than 'len'; go on comparing after the '\0' */
       len++;
       l += len; ll -= len; r += len; lr -= len;
     }
   }
 }
 
 
 /*
 ** Check whether integer 'i' is less than float 'f'. If 'i' has an
 ** exact representation as a float ('l_intfitsf'), compare numbers as
 ** floats. Otherwise, if 'f' is outside the range for integers, result
 ** is trivial. Otherwise, compare them as integers. (When 'i' has no
 ** float representation, either 'f' is "far away" from 'i' or 'f' has
 ** no precision left for a fractional part; either way, how 'f' is
 ** truncated is irrelevant.) When 'f' is NaN, comparisons must result
 ** in false.
 */
 static int LTintfloat (lua_Integer i, lua_Number f) {
 #if defined(l_intfitsf)
   if (!l_intfitsf(i)) {
     if (f >= -cast_num(LUA_MININTEGER))  /* -minint == maxint + 1 */
       return 1;  /* f >= maxint + 1 > i */
     else if (f > cast_num(LUA_MININTEGER))  /* minint < f <= maxint ? */
       return (i < cast(lua_Integer, f));  /* compare them as integers */
     else  /* f <= minint <= i (or 'f' is NaN)  -->  not(i < f) */
       return 0;
   }
 #endif
   return luai_numlt(cast_num(i), f);  /* compare them as floats */
 }
 
 
 /*
 ** Check whether integer 'i' is less than or equal to float 'f'.
 ** See comments on previous function.
 */
 static int LEintfloat (lua_Integer i, lua_Number f) {
 #if defined(l_intfitsf)
   if (!l_intfitsf(i)) {
     if (f >= -cast_num(LUA_MININTEGER))  /* -minint == maxint + 1 */
       return 1;  /* f >= maxint + 1 > i */
     else if (f >= cast_num(LUA_MININTEGER))  /* minint <= f <= maxint ? */
       return (i <= cast(lua_Integer, f));  /* compare them as integers */
     else  /* f < minint <= i (or 'f' is NaN)  -->  not(i <= f) */
       return 0;
   }
 #endif
   return luai_numle(cast_num(i), f);  /* compare them as floats */
 }
 
 
 /*
 ** Return 'l < r', for numbers.
 */
 static int LTnum (const TValue *l, const TValue *r) {
   if (ttisinteger(l)) {
     lua_Integer li = ivalue(l);
     if (ttisinteger(r))
       return li < ivalue(r);  /* both are integers */
     else  /* 'l' is int and 'r' is float */
       return LTintfloat(li, fltvalue(r));  /* l < r ? */
   }
   else {
     lua_Number lf = fltvalue(l);  /* 'l' must be float */
     if (ttisfloat(r))
       return luai_numlt(lf, fltvalue(r));  /* both are float */
     else if (luai_numisnan(lf))  /* 'r' is int and 'l' is float */
       return 0;  /* NaN < i is always false */
     else  /* without NaN, (l < r)  <-->  not(r <= l) */
       return !LEintfloat(ivalue(r), lf);  /* not (r <= l) ? */
   }
 }
 
 
 /*
 ** Return 'l <= r', for numbers.
 */
 static int LEnum (const TValue *l, const TValue *r) {
   if (ttisinteger(l)) {
     lua_Integer li = ivalue(l);
     if (ttisinteger(r))
       return li <= ivalue(r);  /* both are integers */
     else  /* 'l' is int and 'r' is float */
       return LEintfloat(li, fltvalue(r));  /* l <= r ? */
   }
   else {
     lua_Number lf = fltvalue(l);  /* 'l' must be float */
     if (ttisfloat(r))
       return luai_numle(lf, fltvalue(r));  /* both are float */
     else if (luai_numisnan(lf))  /* 'r' is int and 'l' is float */
       return 0;  /*  NaN <= i is always false */
     else  /* without NaN, (l <= r)  <-->  not(r < l) */
       return !LTintfloat(ivalue(r), lf);  /* not (r < l) ? */
   }
 }
 
 
 /*
 ** Main operation less than; return 'l < r'.
 */
 int luaV_lessthan (lua_State *L, const TValue *l, const TValue *r) {
   int res;
   if (ttisnumber(l) && ttisnumber(r))  /* both operands are numbers? */
     return LTnum(l, r);
   else if (ttisstring(l) && ttisstring(r))  /* both are strings? */
     return l_strcmp(tsvalue(l), tsvalue(r)) < 0;
   else if ((res = luaT_callorderTM(L, l, r, TM_LT)) < 0)  /* no metamethod? */
     luaG_ordererror(L, l, r);  /* error */
   return res;
 }
 
 
 /*
 ** Main operation less than or equal to; return 'l <= r'. If it needs
 ** a metamethod and there is no '__le', try '__lt', based on
 ** l <= r iff !(r < l) (assuming a total order). If the metamethod
 ** yields during this substitution, the continuation has to know
 ** about it (to negate the result of r<l); bit CIST_LEQ in the call
 ** status keeps that information.
 */
 int luaV_lessequal (lua_State *L, const TValue *l, const TValue *r) {
   int res;
   if (ttisnumber(l) && ttisnumber(r))  /* both operands are numbers? */
     return LEnum(l, r);
   else if (ttisstring(l) && ttisstring(r))  /* both are strings? */
     return l_strcmp(tsvalue(l), tsvalue(r)) <= 0;
   else if ((res = luaT_callorderTM(L, l, r, TM_LE)) >= 0)  /* try 'le' */
     return res;
   else {  /* try 'lt': */
     L->ci->callstatus |= CIST_LEQ;  /* mark it is doing 'lt' for 'le' */
     res = luaT_callorderTM(L, r, l, TM_LT);
     L->ci->callstatus ^= CIST_LEQ;  /* clear mark */
     if (res < 0)
       luaG_ordererror(L, l, r);
     return !res;  /* result is negated */
   }
 }
 
 
 /*
 ** Main operation for equality of Lua values; return 't1 == t2'.
 ** L == NULL means raw equality (no metamethods)
 */
 int luaV_equalobj (lua_State *L, const TValue *t1, const TValue *t2) {
   const TValue *tm;
   if (ttype(t1) != ttype(t2)) {  /* not the same variant? */
     if (ttnov(t1) != ttnov(t2) || ttnov(t1) != LUA_TNUMBER)
       return 0;  /* only numbers can be equal with different variants */
     else {  /* two numbers with different variants */
       lua_Integer i1, i2;  /* compare them as integers */
       return (tointeger(t1, &i1) && tointeger(t2, &i2) && i1 == i2);
     }
   }
   /* values have same type and same variant */
   switch (ttype(t1)) {
     case LUA_TNIL: return 1;
     case LUA_TNUMINT: return (ivalue(t1) == ivalue(t2));
     case LUA_TNUMFLT: return luai_numeq(fltvalue(t1), fltvalue(t2));
     case LUA_TBOOLEAN: return bvalue(t1) == bvalue(t2);  /* true must be 1 !! */
     case LUA_TLIGHTUSERDATA: return pvalue(t1) == pvalue(t2);
     case LUA_TLCF: return fvalue(t1) == fvalue(t2);
     case LUA_TSHRSTR: return eqshrstr(tsvalue(t1), tsvalue(t2));
     case LUA_TLNGSTR: return luaS_eqlngstr(tsvalue(t1), tsvalue(t2));
     case LUA_TUSERDATA: {
       if (uvalue(t1) == uvalue(t2)) return 1;
       else if (L == NULL) return 0;
       tm = fasttm(L, uvalue(t1)->metatable, TM_EQ);
       if (tm == NULL)
         tm = fasttm(L, uvalue(t2)->metatable, TM_EQ);
       break;  /* will try TM */
     }
     case LUA_TTABLE: {
       if (hvalue(t1) == hvalue(t2)) return 1;
       else if (L == NULL) return 0;
       tm = fasttm(L, hvalue(t1)->metatable, TM_EQ);
       if (tm == NULL)
         tm = fasttm(L, hvalue(t2)->metatable, TM_EQ);
       break;  /* will try TM */
     }
     default:
       return gcvalue(t1) == gcvalue(t2);
   }
   if (tm == NULL)  /* no TM? */
     return 0;  /* objects are different */
   luaT_callTM(L, tm, t1, t2, L->top, 1);  /* call TM */
   return !l_isfalse(L->top);
 }
 
 
 /* macro used by 'luaV_concat' to ensure that element at 'o' is a string */
 #define tostring(L,o)  \
 	(ttisstring(o) || (cvt2str(o) && (luaO_tostring(L, o), 1)))
 
 #define isemptystr(o)	(ttisshrstring(o) && tsvalue(o)->shrlen == 0)
 
 /* copy strings in stack from top - n up to top - 1 to buffer */
 static void copy2buff (StkId top, int n, char *buff) {
   size_t tl = 0;  /* size already copied */
   do {
     size_t l = vslen(top - n);  /* length of string being copied */
     memcpy(buff + tl, svalue(top - n), l * sizeof(char));
     tl += l;
   } while (--n > 0);
 }
 
 
 /*
 ** Main operation for concatenation: concat 'total' values in the stack,
 ** from 'L->top - total' up to 'L->top - 1'.
 */
 void luaV_concat (lua_State *L, int total) {
   lua_assert(total >= 2);
   do {
     StkId top = L->top;
     int n = 2;  /* number of elements handled in this pass (at least 2) */
     if (!(ttisstring(top-2) || cvt2str(top-2)) || !tostring(L, top-1))
       luaT_trybinTM(L, top-2, top-1, top-2, TM_CONCAT);
     else if (isemptystr(top - 1))  /* second operand is empty? */
       cast_void(tostring(L, top - 2));  /* result is first operand */
     else if (isemptystr(top - 2)) {  /* first operand is an empty string? */
       setobjs2s(L, top - 2, top - 1);  /* result is second op. */
     }
     else {
       /* at least two non-empty string values; get as many as possible */
       size_t tl = vslen(top - 1);
       TString *ts;
       /* collect total length and number of strings */
       for (n = 1; n < total && tostring(L, top - n - 1); n++) {
         size_t l = vslen(top - n - 1);
         if (l >= (MAX_SIZE/sizeof(char)) - tl)
           luaG_runerror(L, "string length overflow");
         tl += l;
       }
       if (tl <= LUAI_MAXSHORTLEN) {  /* is result a short string? */
         char buff[LUAI_MAXSHORTLEN];
         copy2buff(top, n, buff);  /* copy strings to buffer */
         ts = luaS_newlstr(L, buff, tl);
       }
       else {  /* long string; copy strings directly to final result */
         ts = luaS_createlngstrobj(L, tl);
         copy2buff(top, n, getstr(ts));
       }
       setsvalue2s(L, top - n, ts);  /* create result */
     }
     total -= n-1;  /* got 'n' strings to create 1 new */
     L->top -= n-1;  /* popped 'n' strings and pushed one */
   } while (total > 1);  /* repeat until only 1 result left */
 }
 
 
 /*
 ** Main operation 'ra' = #rb'.
 */
 void luaV_objlen (lua_State *L, StkId ra, const TValue *rb) {
   const TValue *tm;
   switch (ttype(rb)) {
     case LUA_TTABLE: {
       Table *h = hvalue(rb);
       tm = fasttm(L, h->metatable, TM_LEN);
       if (tm) break;  /* metamethod? break switch to call it */
       setivalue(ra, luaH_getn(h));  /* else primitive len */
       return;
     }
     case LUA_TSHRSTR: {
       setivalue(ra, tsvalue(rb)->shrlen);
       return;
     }
     case LUA_TLNGSTR: {
       setivalue(ra, tsvalue(rb)->u.lnglen);
       return;
     }
     default: {  /* try metamethod */
       tm = luaT_gettmbyobj(L, rb, TM_LEN);
       if (ttisnil(tm))  /* no metamethod? */
         luaG_typeerror(L, rb, "get length of");
       break;
     }
   }
   luaT_callTM(L, tm, rb, rb, ra, 1);
 }
 
 
 /*
 ** Integer division; return 'm // n', that is, floor(m/n).
 ** C division truncates its result (rounds towards zero).
 ** 'floor(q) == trunc(q)' when 'q >= 0' or when 'q' is integer,
 ** otherwise 'floor(q) == trunc(q) - 1'.
 */
 lua_Integer luaV_div (lua_State *L, lua_Integer m, lua_Integer n) {
   if (l_castS2U(n) + 1u <= 1u) {  /* special cases: -1 or 0 */
     if (n == 0)
       luaG_runerror(L, "attempt to divide by zero");
     return intop(-, 0, m);   /* n==-1; avoid overflow with 0x80000...//-1 */
   }
   else {
     lua_Integer q = m / n;  /* perform C division */
     if ((m ^ n) < 0 && m % n != 0)  /* 'm/n' would be negative non-integer? */
       q -= 1;  /* correct result for different rounding */
     return q;
   }
 }
 
 
 /*
 ** Integer modulus; return 'm % n'. (Assume that C '%' with
 ** negative operands follows C99 behavior. See previous comment
 ** about luaV_div.)
 */
 lua_Integer luaV_mod (lua_State *L, lua_Integer m, lua_Integer n) {
   if (l_castS2U(n) + 1u <= 1u) {  /* special cases: -1 or 0 */
     if (n == 0)
       luaG_runerror(L, "attempt to perform 'n%%0'");
     return 0;   /* m % -1 == 0; avoid overflow with 0x80000...%-1 */
   }
   else {
     lua_Integer r = m % n;
     if (r != 0 && (m ^ n) < 0)  /* 'm/n' would be non-integer negative? */
       r += n;  /* correct result for different rounding */
     return r;
   }
 }
 
 
 /* number of bits in an integer */
 #define NBITS	cast_int(sizeof(lua_Integer) * CHAR_BIT)
 
 /*
 ** Shift left operation. (Shift right just negates 'y'.)
 */
 lua_Integer luaV_shiftl (lua_Integer x, lua_Integer y) {
   if (y < 0) {  /* shift right? */
     if (y <= -NBITS) return 0;
     else return intop(>>, x, -y);
   }
   else {  /* shift left */
     if (y >= NBITS) return 0;
     else return intop(<<, x, y);
   }
 }
 
 
 /*
 ** check whether cached closure in prototype 'p' may be reused, that is,
 ** whether there is a cached closure with the same upvalues needed by
 ** new closure to be created.
 */
 static LClosure *getcached (Proto *p, UpVal **encup, StkId base) {
   LClosure *c = p->cache;
   if (c != NULL) {  /* is there a cached closure? */
     int nup = p->sizeupvalues;
     Upvaldesc *uv = p->upvalues;
     int i;
     for (i = 0; i < nup; i++) {  /* check whether it has right upvalues */
       TValue *v = uv[i].instack ? base + uv[i].idx : encup[uv[i].idx]->v;
       if (c->upvals[i]->v != v)
         return NULL;  /* wrong upvalue; cannot reuse closure */
     }
   }
   return c;  /* return cached closure (or NULL if no cached closure) */
 }
 
 
 /*
 ** create a new Lua closure, push it in the stack, and initialize
 ** its upvalues. Note that the closure is not cached if prototype is
 ** already black (which means that 'cache' was already cleared by the
 ** GC).
 */
 static void pushclosure (lua_State *L, Proto *p, UpVal **encup, StkId base,
                          StkId ra) {
   int nup = p->sizeupvalues;
   Upvaldesc *uv = p->upvalues;
   int i;
   LClosure *ncl = luaF_newLclosure(L, nup);
   ncl->p = p;
   setclLvalue(L, ra, ncl);  /* anchor new closure in stack */
   for (i = 0; i < nup; i++) {  /* fill in its upvalues */
     if (uv[i].instack)  /* upvalue refers to local variable? */
       ncl->upvals[i] = luaF_findupval(L, base + uv[i].idx);
     else  /* get upvalue from enclosing function */
       ncl->upvals[i] = encup[uv[i].idx];
     ncl->upvals[i]->refcount++;
     /* new closure is white, so we do not need a barrier here */
   }
   if (!isblack(p))  /* cache will not break GC invariant? */
     p->cache = ncl;  /* save it on cache for reuse */
 }
 
 
 /*
 ** finish execution of an opcode interrupted by an yield
 */
 void luaV_finishOp (lua_State *L) {
   CallInfo *ci = L->ci;
   StkId base = ci->u.l.base;
   Instruction inst = *(ci->u.l.savedpc - 1);  /* interrupted instruction */
   OpCode op = GET_OPCODE(inst);
   switch (op) {  /* finish its execution */
     case OP_ADD: case OP_SUB: case OP_MUL: case OP_DIV: case OP_IDIV:
     case OP_BAND: case OP_BOR: case OP_BXOR: case OP_SHL: case OP_SHR:
     case OP_MOD: case OP_POW:
     case OP_UNM: case OP_BNOT: case OP_LEN:
     case OP_GETTABUP: case OP_GETTABLE: case OP_SELF: {
       setobjs2s(L, base + GETARG_A(inst), --L->top);
       break;
     }
     case OP_LE: case OP_LT: case OP_EQ: {
       int res = !l_isfalse(L->top - 1);
       L->top--;
       if (ci->callstatus & CIST_LEQ) {  /* "<=" using "<" instead? */
         lua_assert(op == OP_LE);
         ci->callstatus ^= CIST_LEQ;  /* clear mark */
         res = !res;  /* negate result */
       }
       lua_assert(GET_OPCODE(*ci->u.l.savedpc) == OP_JMP);
       if (res != GETARG_A(inst))  /* condition failed? */
         ci->u.l.savedpc++;  /* skip jump instruction */
       break;
     }
     case OP_CONCAT: {
       StkId top = L->top - 1;  /* top when 'luaT_trybinTM' was called */
       int b = GETARG_B(inst);      /* first element to concatenate */
       int total = cast_int(top - 1 - (base + b));  /* yet to concatenate */
       setobj2s(L, top - 2, top);  /* put TM result in proper position */
       if (total > 1) {  /* are there elements to concat? */
         L->top = top - 1;  /* top is one after last element (at top-2) */
         luaV_concat(L, total);  /* concat them (may yield again) */
       }
       /* move final result to final position */
       setobj2s(L, ci->u.l.base + GETARG_A(inst), L->top - 1);
       L->top = ci->top;  /* restore top */
       break;
     }
     case OP_TFORCALL: {
       lua_assert(GET_OPCODE(*ci->u.l.savedpc) == OP_TFORLOOP);
       L->top = ci->top;  /* correct top */
       break;
     }
     case OP_CALL: {
       if (GETARG_C(inst) - 1 >= 0)  /* nresults >= 0? */
         L->top = ci->top;  /* adjust results */
       break;
     }
     case OP_TAILCALL: case OP_SETTABUP: case OP_SETTABLE:
       break;
     default: lua_assert(0);
   }
 }
 
 
 
 
 /*
 ** {==================================================================
 ** Function 'luaV_execute': main interpreter loop
 ** ===================================================================
 */
 
 
 /*
 ** some macros for common tasks in 'luaV_execute'
 */
 
 
 #define RA(i)	(base+GETARG_A(i))
 #define RB(i)	check_exp(getBMode(GET_OPCODE(i)) == OpArgR, base+GETARG_B(i))
 #define RC(i)	check_exp(getCMode(GET_OPCODE(i)) == OpArgR, base+GETARG_C(i))
 #define RKB(i)	check_exp(getBMode(GET_OPCODE(i)) == OpArgK, \
 	ISK(GETARG_B(i)) ? k+INDEXK(GETARG_B(i)) : base+GETARG_B(i))
 #define RKC(i)	check_exp(getCMode(GET_OPCODE(i)) == OpArgK, \
 	ISK(GETARG_C(i)) ? k+INDEXK(GETARG_C(i)) : base+GETARG_C(i))
 
 
 /* execute a jump instruction */
 #define dojump(ci,i,e) \
   { int a = GETARG_A(i); \
     if (a != 0) luaF_close(L, ci->u.l.base + a - 1); \
     ci->u.l.savedpc += GETARG_sBx(i) + e; }
 
 /* for test instructions, execute the jump instruction that follows it */
 #define donextjump(ci)	{ i = *ci->u.l.savedpc; dojump(ci, i, 1); }
 
 
 #define Protect(x)	{ {x;}; base = ci->u.l.base; }
 
 #define checkGC(L,c)  \
 	{ luaC_condGC(L, L->top = (c),  /* limit of live values */ \
                          Protect(L->top = ci->top));  /* restore top */ \
            luai_threadyield(L); }
 
 
 /* fetch an instruction and prepare its execution */
 #define vmfetch()	{ \
   i = *(ci->u.l.savedpc++); \
   if (L->hookmask & (LUA_MASKLINE | LUA_MASKCOUNT)) \
     Protect(luaG_traceexec(L)); \
   ra = RA(i); /* WARNING: any stack reallocation invalidates 'ra' */ \
   lua_assert(base == ci->u.l.base); \
   lua_assert(base <= L->top && L->top < L->stack + L->stacksize); \
 }
 
 #define vmdispatch(o)	switch(o)
 #define vmcase(l)	case l:
 #define vmbreak		break
 
 
 /*
 ** copy of 'luaV_gettable', but protecting the call to potential
 ** metamethod (which can reallocate the stack)
 */
 #define gettableProtected(L,t,k,v)  { const TValue *slot; \
   if (luaV_fastget(L,t,k,slot,luaH_get)) { setobj2s(L, v, slot); } \
   else Protect(luaV_finishget(L,t,k,v,slot)); }
 
 
 /* same for 'luaV_settable' */
 #define settableProtected(L,t,k,v) { const TValue *slot; \
   if (!luaV_fastset(L,t,k,slot,luaH_get,v)) \
     Protect(luaV_finishset(L,t,k,v,slot)); }
 
 
 
 void luaV_execute (lua_State *L) {
   CallInfo *ci = L->ci;
   LClosure *cl;
   TValue *k;
   StkId base;
   ci->callstatus |= CIST_FRESH;  /* fresh invocation of 'luaV_execute" */
  newframe:  /* reentry point when frame changes (call/return) */
   lua_assert(ci == L->ci);
   cl = clLvalue(ci->func);  /* local reference to function's closure */
   k = cl->p->k;  /* local reference to function's constant table */
   base = ci->u.l.base;  /* local copy of function's base */
   /* main loop of interpreter */
   for (;;) {
     Instruction i;
     StkId ra;
     vmfetch();
     vmdispatch (GET_OPCODE(i)) {
       vmcase(OP_MOVE) {
         setobjs2s(L, ra, RB(i));
         vmbreak;
       }
       vmcase(OP_LOADK) {
         TValue *rb = k + GETARG_Bx(i);
         setobj2s(L, ra, rb);
         vmbreak;
       }
       vmcase(OP_LOADKX) {
         TValue *rb;
         lua_assert(GET_OPCODE(*ci->u.l.savedpc) == OP_EXTRAARG);
         rb = k + GETARG_Ax(*ci->u.l.savedpc++);
         setobj2s(L, ra, rb);
         vmbreak;
       }
       vmcase(OP_LOADBOOL) {
         setbvalue(ra, GETARG_B(i));
         if (GETARG_C(i)) ci->u.l.savedpc++;  /* skip next instruction (if C) */
         vmbreak;
       }
       vmcase(OP_LOADNIL) {
         int b = GETARG_B(i);
         do {
           setnilvalue(ra++);
         } while (b--);
         vmbreak;
       }
       vmcase(OP_GETUPVAL) {
         int b = GETARG_B(i);
         setobj2s(L, ra, cl->upvals[b]->v);
         vmbreak;
       }
       vmcase(OP_GETTABUP) {
         TValue *upval = cl->upvals[GETARG_B(i)]->v;
         TValue *rc = RKC(i);
         gettableProtected(L, upval, rc, ra);
         vmbreak;
       }
       vmcase(OP_GETTABLE) {
         StkId rb = RB(i);
         TValue *rc = RKC(i);
         gettableProtected(L, rb, rc, ra);
         vmbreak;
       }
       vmcase(OP_SETTABUP) {
         TValue *upval = cl->upvals[GETARG_A(i)]->v;
         TValue *rb = RKB(i);
         TValue *rc = RKC(i);
         settableProtected(L, upval, rb, rc);
         vmbreak;
       }
       vmcase(OP_SETUPVAL) {
         UpVal *uv = cl->upvals[GETARG_B(i)];
         setobj(L, uv->v, ra);
         luaC_upvalbarrier(L, uv);
         vmbreak;
       }
       vmcase(OP_SETTABLE) {
         TValue *rb = RKB(i);
         TValue *rc = RKC(i);
         settableProtected(L, ra, rb, rc);
         vmbreak;
       }
       vmcase(OP_NEWTABLE) {
         int b = GETARG_B(i);
         int c = GETARG_C(i);
         Table *t = luaH_new(L);
         sethvalue(L, ra, t);
         if (b != 0 || c != 0)
           luaH_resize(L, t, luaO_fb2int(b), luaO_fb2int(c));
         checkGC(L, ra + 1);
         vmbreak;
       }
       vmcase(OP_SELF) {
         const TValue *aux;
         StkId rb = RB(i);
         TValue *rc = RKC(i);
         TString *key = tsvalue(rc);  /* key must be a string */
         setobjs2s(L, ra + 1, rb);
         if (luaV_fastget(L, rb, key, aux, luaH_getstr)) {
           setobj2s(L, ra, aux);
         }
         else Protect(luaV_finishget(L, rb, rc, ra, aux));
         vmbreak;
       }
       vmcase(OP_ADD) {
         TValue *rb = RKB(i);
         TValue *rc = RKC(i);
         lua_Number nb; lua_Number nc;
         if (ttisinteger(rb) && ttisinteger(rc)) {
           lua_Integer ib = ivalue(rb); lua_Integer ic = ivalue(rc);
           setivalue(ra, intop(+, ib, ic));
         }
         else if (tonumber(rb, &nb) && tonumber(rc, &nc)) {
           setfltvalue(ra, luai_numadd(L, nb, nc));
         }
         else { Protect(luaT_trybinTM(L, rb, rc, ra, TM_ADD)); }
         vmbreak;
       }
       vmcase(OP_SUB) {
         TValue *rb = RKB(i);
         TValue *rc = RKC(i);
         lua_Number nb; lua_Number nc;
         if (ttisinteger(rb) && ttisinteger(rc)) {
           lua_Integer ib = ivalue(rb); lua_Integer ic = ivalue(rc);
           setivalue(ra, intop(-, ib, ic));
         }
         else if (tonumber(rb, &nb) && tonumber(rc, &nc)) {
           setfltvalue(ra, luai_numsub(L, nb, nc));
         }
         else { Protect(luaT_trybinTM(L, rb, rc, ra, TM_SUB)); }
         vmbreak;
       }
       vmcase(OP_MUL) {
         TValue *rb = RKB(i);
         TValue *rc = RKC(i);
         lua_Number nb; lua_Number nc;
         if (ttisinteger(rb) && ttisinteger(rc)) {
           lua_Integer ib = ivalue(rb); lua_Integer ic = ivalue(rc);
           setivalue(ra, intop(*, ib, ic));
         }
         else if (tonumber(rb, &nb) && tonumber(rc, &nc)) {
           setfltvalue(ra, luai_nummul(L, nb, nc));
         }
         else { Protect(luaT_trybinTM(L, rb, rc, ra, TM_MUL)); }
         vmbreak;
       }
       vmcase(OP_DIV) {  /* float division (always with floats) */
         TValue *rb = RKB(i);
         TValue *rc = RKC(i);
         lua_Number nb; lua_Number nc;
         if (tonumber(rb, &nb) && tonumber(rc, &nc)) {
           setfltvalue(ra, luai_numdiv(L, nb, nc));
         }
         else { Protect(luaT_trybinTM(L, rb, rc, ra, TM_DIV)); }
         vmbreak;
       }
       vmcase(OP_BAND) {
         TValue *rb = RKB(i);
         TValue *rc = RKC(i);
         lua_Integer ib; lua_Integer ic;
         if (tointeger(rb, &ib) && tointeger(rc, &ic)) {
           setivalue(ra, intop(&, ib, ic));
         }
         else { Protect(luaT_trybinTM(L, rb, rc, ra, TM_BAND)); }
         vmbreak;
       }
       vmcase(OP_BOR) {
         TValue *rb = RKB(i);
         TValue *rc = RKC(i);
         lua_Integer ib; lua_Integer ic;
         if (tointeger(rb, &ib) && tointeger(rc, &ic)) {
           setivalue(ra, intop(|, ib, ic));
         }
         else { Protect(luaT_trybinTM(L, rb, rc, ra, TM_BOR)); }
         vmbreak;
       }
       vmcase(OP_BXOR) {
         TValue *rb = RKB(i);
         TValue *rc = RKC(i);
         lua_Integer ib; lua_Integer ic;
         if (tointeger(rb, &ib) && tointeger(rc, &ic)) {
           setivalue(ra, intop(^, ib, ic));
         }
         else { Protect(luaT_trybinTM(L, rb, rc, ra, TM_BXOR)); }
         vmbreak;
       }
       vmcase(OP_SHL) {
         TValue *rb = RKB(i);
         TValue *rc = RKC(i);
         lua_Integer ib; lua_Integer ic;
         if (tointeger(rb, &ib) && tointeger(rc, &ic)) {
           setivalue(ra, luaV_shiftl(ib, ic));
         }
         else { Protect(luaT_trybinTM(L, rb, rc, ra, TM_SHL)); }
         vmbreak;
       }
       vmcase(OP_SHR) {
         TValue *rb = RKB(i);
         TValue *rc = RKC(i);
         lua_Integer ib; lua_Integer ic;
         if (tointeger(rb, &ib) && tointeger(rc, &ic)) {
           setivalue(ra, luaV_shiftl(ib, -ic));
         }
         else { Protect(luaT_trybinTM(L, rb, rc, ra, TM_SHR)); }
         vmbreak;
       }
       vmcase(OP_MOD) {
         TValue *rb = RKB(i);
         TValue *rc = RKC(i);
         lua_Number nb; lua_Number nc;
         if (ttisinteger(rb) && ttisinteger(rc)) {
           lua_Integer ib = ivalue(rb); lua_Integer ic = ivalue(rc);
           setivalue(ra, luaV_mod(L, ib, ic));
         }
         else if (tonumber(rb, &nb) && tonumber(rc, &nc)) {
           lua_Number m;
           luai_nummod(L, nb, nc, m);
           setfltvalue(ra, m);
         }
         else { Protect(luaT_trybinTM(L, rb, rc, ra, TM_MOD)); }
         vmbreak;
       }
       vmcase(OP_IDIV) {  /* floor division */
         TValue *rb = RKB(i);
         TValue *rc = RKC(i);
         lua_Number nb; lua_Number nc;
         if (ttisinteger(rb) && ttisinteger(rc)) {
           lua_Integer ib = ivalue(rb); lua_Integer ic = ivalue(rc);
           setivalue(ra, luaV_div(L, ib, ic));
         }
         else if (tonumber(rb, &nb) && tonumber(rc, &nc)) {
           setfltvalue(ra, luai_numidiv(L, nb, nc));
         }
         else { Protect(luaT_trybinTM(L, rb, rc, ra, TM_IDIV)); }
         vmbreak;
       }
       vmcase(OP_POW) {
         TValue *rb = RKB(i);
         TValue *rc = RKC(i);
         lua_Number nb; lua_Number nc;
         if (tonumber(rb, &nb) && tonumber(rc, &nc)) {
           setfltvalue(ra, luai_numpow(L, nb, nc));
         }
         else { Protect(luaT_trybinTM(L, rb, rc, ra, TM_POW)); }
         vmbreak;
       }
       vmcase(OP_UNM) {
         TValue *rb = RB(i);
         lua_Number nb;
         if (ttisinteger(rb)) {
           lua_Integer ib = ivalue(rb);
           setivalue(ra, intop(-, 0, ib));
         }
         else if (tonumber(rb, &nb)) {
           setfltvalue(ra, luai_numunm(L, nb));
         }
         else {
           Protect(luaT_trybinTM(L, rb, rb, ra, TM_UNM));
         }
         vmbreak;
       }
       vmcase(OP_BNOT) {
         TValue *rb = RB(i);
         lua_Integer ib;
         if (tointeger(rb, &ib)) {
           setivalue(ra, intop(^, ~l_castS2U(0), ib));
         }
         else {
           Protect(luaT_trybinTM(L, rb, rb, ra, TM_BNOT));
         }
         vmbreak;
       }
       vmcase(OP_NOT) {
         TValue *rb = RB(i);
         int res = l_isfalse(rb);  /* next assignment may change this value */
         setbvalue(ra, res);
         vmbreak;
       }
       vmcase(OP_LEN) {
         Protect(luaV_objlen(L, ra, RB(i)));
         vmbreak;
       }
       vmcase(OP_CONCAT) {
         int b = GETARG_B(i);
         int c = GETARG_C(i);
         StkId rb;
         L->top = base + c + 1;  /* mark the end of concat operands */
         Protect(luaV_concat(L, c - b + 1));
         ra = RA(i);  /* 'luaV_concat' may invoke TMs and move the stack */
         rb = base + b;
         setobjs2s(L, ra, rb);
         checkGC(L, (ra >= rb ? ra + 1 : rb));
         L->top = ci->top;  /* restore top */
         vmbreak;
       }
       vmcase(OP_JMP) {
         dojump(ci, i, 0);
         vmbreak;
       }
       vmcase(OP_EQ) {
         TValue *rb = RKB(i);
         TValue *rc = RKC(i);
         Protect(
           if (luaV_equalobj(L, rb, rc) != GETARG_A(i))
             ci->u.l.savedpc++;
           else
             donextjump(ci);
         )
         vmbreak;
       }
       vmcase(OP_LT) {
         Protect(
           if (luaV_lessthan(L, RKB(i), RKC(i)) != GETARG_A(i))
             ci->u.l.savedpc++;
           else
             donextjump(ci);
         )
         vmbreak;
       }
       vmcase(OP_LE) {
         Protect(
           if (luaV_lessequal(L, RKB(i), RKC(i)) != GETARG_A(i))
             ci->u.l.savedpc++;
           else
             donextjump(ci);
         )
         vmbreak;
       }
       vmcase(OP_TEST) {
         if (GETARG_C(i) ? l_isfalse(ra) : !l_isfalse(ra))
             ci->u.l.savedpc++;
           else
           donextjump(ci);
         vmbreak;
       }
       vmcase(OP_TESTSET) {
         TValue *rb = RB(i);
         if (GETARG_C(i) ? l_isfalse(rb) : !l_isfalse(rb))
           ci->u.l.savedpc++;
         else {
           setobjs2s(L, ra, rb);
           donextjump(ci);
         }
         vmbreak;
       }
       vmcase(OP_CALL) {
         int b = GETARG_B(i);
         int nresults = GETARG_C(i) - 1;
         if (b != 0) L->top = ra+b;  /* else previous instruction set top */
         if (luaD_precall(L, ra, nresults)) {  /* C function? */
           if (nresults >= 0)
             L->top = ci->top;  /* adjust results */
           Protect((void)0);  /* update 'base' */
         }
         else {  /* Lua function */
           ci = L->ci;
           goto newframe;  /* restart luaV_execute over new Lua function */
         }
         vmbreak;
       }
       vmcase(OP_TAILCALL) {
         int b = GETARG_B(i);
         if (b != 0) L->top = ra+b;  /* else previous instruction set top */
         lua_assert(GETARG_C(i) - 1 == LUA_MULTRET);
         if (luaD_precall(L, ra, LUA_MULTRET)) {  /* C function? */
           Protect((void)0);  /* update 'base' */
         }
         else {
           /* tail call: put called frame (n) in place of caller one (o) */
           CallInfo *nci = L->ci;  /* called frame */
           CallInfo *oci = nci->previous;  /* caller frame */
           StkId nfunc = nci->func;  /* called function */
           StkId ofunc = oci->func;  /* caller function */
           /* last stack slot filled by 'precall' */
           StkId lim = nci->u.l.base + getproto(nfunc)->numparams;
           int aux;
           /* close all upvalues from previous call */
           if (cl->p->sizep > 0) luaF_close(L, oci->u.l.base);
           /* move new frame into old one */
           for (aux = 0; nfunc + aux < lim; aux++)
             setobjs2s(L, ofunc + aux, nfunc + aux);
           oci->u.l.base = ofunc + (nci->u.l.base - nfunc);  /* correct base */
           oci->top = L->top = ofunc + (L->top - nfunc);  /* correct top */
           oci->u.l.savedpc = nci->u.l.savedpc;
           oci->callstatus |= CIST_TAIL;  /* function was tail called */
           ci = L->ci = oci;  /* remove new frame */
           lua_assert(L->top == oci->u.l.base + getproto(ofunc)->maxstacksize);
           goto newframe;  /* restart luaV_execute over new Lua function */
         }
         vmbreak;
       }
       vmcase(OP_RETURN) {
         int b = GETARG_B(i);
         if (cl->p->sizep > 0) luaF_close(L, base);
         b = luaD_poscall(L, ci, ra, (b != 0 ? b - 1 : cast_int(L->top - ra)));
         if (ci->callstatus & CIST_FRESH)  /* local 'ci' still from callee */
           return;  /* external invocation: return */
         else {  /* invocation via reentry: continue execution */
           ci = L->ci;
           if (b) L->top = ci->top;
           lua_assert(isLua(ci));
           lua_assert(GET_OPCODE(*((ci)->u.l.savedpc - 1)) == OP_CALL);
           goto newframe;  /* restart luaV_execute over new Lua function */
         }
       }
       vmcase(OP_FORLOOP) {
         if (ttisinteger(ra)) {  /* integer loop? */
           lua_Integer step = ivalue(ra + 2);
           lua_Integer idx = intop(+, ivalue(ra), step); /* increment index */
           lua_Integer limit = ivalue(ra + 1);
           if ((0 < step) ? (idx <= limit) : (limit <= idx)) {
             ci->u.l.savedpc += GETARG_sBx(i);  /* jump back */
             chgivalue(ra, idx);  /* update internal index... */
             setivalue(ra + 3, idx);  /* ...and external index */
           }
         }
         else {  /* floating loop */
           lua_Number step = fltvalue(ra + 2);
           lua_Number idx = luai_numadd(L, fltvalue(ra), step); /* inc. index */
           lua_Number limit = fltvalue(ra + 1);
           if (luai_numlt(0, step) ? luai_numle(idx, limit)
                                   : luai_numle(limit, idx)) {
             ci->u.l.savedpc += GETARG_sBx(i);  /* jump back */
             chgfltvalue(ra, idx);  /* update internal index... */
             setfltvalue(ra + 3, idx);  /* ...and external index */
           }
         }
         vmbreak;
       }
       vmcase(OP_FORPREP) {
         TValue *init = ra;
         TValue *plimit = ra + 1;
         TValue *pstep = ra + 2;
         lua_Integer ilimit;
         int stopnow;
         if (ttisinteger(init) && ttisinteger(pstep) &&
             forlimit(plimit, &ilimit, ivalue(pstep), &stopnow)) {
           /* all values are integer */
           lua_Integer initv = (stopnow ? 0 : ivalue(init));
           setivalue(plimit, ilimit);
           setivalue(init, intop(-, initv, ivalue(pstep)));
         }
         else {  /* try making all values floats */
           lua_Number ninit; lua_Number nlimit; lua_Number nstep;
           if (!tonumber(plimit, &nlimit))
             luaG_runerror(L, "'for' limit must be a number");
           setfltvalue(plimit, nlimit);
           if (!tonumber(pstep, &nstep))
             luaG_runerror(L, "'for' step must be a number");
           setfltvalue(pstep, nstep);
           if (!tonumber(init, &ninit))
             luaG_runerror(L, "'for' initial value must be a number");
           setfltvalue(init, luai_numsub(L, ninit, nstep));
         }
         ci->u.l.savedpc += GETARG_sBx(i);
         vmbreak;
       }
       vmcase(OP_TFORCALL) {
         StkId cb = ra + 3;  /* call base */
         setobjs2s(L, cb+2, ra+2);
         setobjs2s(L, cb+1, ra+1);
         setobjs2s(L, cb, ra);
         L->top = cb + 3;  /* func. + 2 args (state and index) */
         Protect(luaD_call(L, cb, GETARG_C(i)));
         L->top = ci->top;
         i = *(ci->u.l.savedpc++);  /* go to next instruction */
         ra = RA(i);
         lua_assert(GET_OPCODE(i) == OP_TFORLOOP);
         goto l_tforloop;
       }
       vmcase(OP_TFORLOOP) {
         l_tforloop:
         if (!ttisnil(ra + 1)) {  /* continue loop? */
           setobjs2s(L, ra, ra + 1);  /* save control variable */
            ci->u.l.savedpc += GETARG_sBx(i);  /* jump back */
         }
         vmbreak;
       }
       vmcase(OP_SETLIST) {
         int n = GETARG_B(i);
         int c = GETARG_C(i);
         unsigned int last;
         Table *h;
         if (n == 0) n = cast_int(L->top - ra) - 1;
         if (c == 0) {
           lua_assert(GET_OPCODE(*ci->u.l.savedpc) == OP_EXTRAARG);
           c = GETARG_Ax(*ci->u.l.savedpc++);
         }
         h = hvalue(ra);
         last = ((c-1)*LFIELDS_PER_FLUSH) + n;
         if (last > h->sizearray)  /* needs more space? */
           luaH_resizearray(L, h, last);  /* preallocate it at once */
         for (; n > 0; n--) {
           TValue *val = ra+n;
           luaH_setint(L, h, last--, val);
           luaC_barrierback(L, h, val);
         }
         L->top = ci->top;  /* correct top (in case of previous open call) */
         vmbreak;
       }
       vmcase(OP_CLOSURE) {
         Proto *p = cl->p->p[GETARG_Bx(i)];
         LClosure *ncl = getcached(p, cl->upvals, base);  /* cached closure */
         if (ncl == NULL)  /* no match? */
           pushclosure(L, p, cl->upvals, base, ra);  /* create a new one */
         else
           setclLvalue(L, ra, ncl);  /* push cashed closure */
         checkGC(L, ra + 1);
         vmbreak;
       }
       vmcase(OP_VARARG) {
         int b = GETARG_B(i) - 1;  /* required results */
         int j;
         int n = cast_int(base - ci->func) - cl->p->numparams - 1;
         if (n < 0)  /* less arguments than parameters? */
           n = 0;  /* no vararg arguments */
         if (b < 0) {  /* B == 0? */
           b = n;  /* get all var. arguments */
           Protect(luaD_checkstack(L, n));
           ra = RA(i);  /* previous call may change the stack */
           L->top = ra + n;
         }
         for (j = 0; j < b && j < n; j++)
           setobjs2s(L, ra + j, base - n + j);
         for (; j < b; j++)  /* complete required results with nil */
           setnilvalue(ra + j);
         vmbreak;
       }
       vmcase(OP_EXTRAARG) {
         lua_assert(0);
         vmbreak;
       }
     }
   }
 }
 
 /* }================================================================== */