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roberto-ieruroberto-ieru
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new opcodes 'FORLOOP1'/'FORPREP1' for "basic for" (integer variable
with increment of 1)
1 parent ab07005 commit d388c16

4 files changed

Lines changed: 73 additions & 18 deletions

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‎lopcodes.c‎

Lines changed: 5 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,5 @@
11
/*
2-
** $Id: lopcodes.c,v 1.72 2017/12/04 17:41:30 roberto Exp roberto $
2+
** $Id: lopcodes.c,v 1.73 2017/12/13 18:32:09 roberto Exp roberto $
33
** Opcodes for Lua virtual machine
44
** See Copyright Notice in lua.h
55
*/
@@ -82,6 +82,8 @@ LUAI_DDEF const char *const luaP_opnames[NUM_OPCODES+1] = {
8282
"RETURN",
8383
"RETURN0",
8484
"RETURN1",
85+
"FORLOOP1",
86+
"FORPREP1",
8587
"FORLOOP",
8688
"FORPREP",
8789
"TFORCALL",
@@ -160,6 +162,8 @@ LUAI_DDEF const lu_byte luaP_opmodes[NUM_OPCODES] = {
160162
,opmode(0, 0, iABC) /* OP_RETURN */
161163
,opmode(0, 0, iABC) /* OP_RETURN0 */
162164
,opmode(0, 0, iABC) /* OP_RETURN1 */
165+
,opmode(0, 1, iABx) /* OP_FORLOOP1 */
166+
,opmode(0, 1, iABx) /* OP_FORPREP1 */
163167
,opmode(0, 1, iABx) /* OP_FORLOOP */
164168
,opmode(0, 1, iABx) /* OP_FORPREP */
165169
,opmode(0, 0, iABC) /* OP_TFORCALL */

‎lopcodes.h‎

Lines changed: 5 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,5 @@
11
/*
2-
** $Id: lopcodes.h,v 1.178 2017/12/15 18:35:22 roberto Exp roberto $
2+
** $Id: lopcodes.h,v 1.179 2017/12/15 18:53:48 roberto Exp roberto $
33
** Opcodes for Lua virtual machine
44
** See Copyright Notice in lua.h
55
*/
@@ -267,6 +267,10 @@ OP_RETURN,/* A B return R(A), ... ,R(A+B-2) (see note) */
267267
OP_RETURN0,/* return */
268268
OP_RETURN1,/* A return R(A) */
269269

270+
OP_FORLOOP1,/* A Bx R(A)++;
271+
if R(A) <= R(A+1) then { pc-=Bx; R(A+3)=R(A) } */
272+
OP_FORPREP1,/* A Bx R(A)--; pc+=Bx */
273+
270274
OP_FORLOOP,/* A Bx R(A)+=R(A+2);
271275
if R(A) <?= R(A+1) then { pc-=Bx; R(A+3)=R(A) } */
272276
OP_FORPREP,/* A Bx R(A)-=R(A+2); pc+=Bx */

‎lparser.c‎

Lines changed: 36 additions & 15 deletions
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,5 @@
11
/*
2-
** $Id: lparser.c,v 2.172 2017/12/15 13:07:10 roberto Exp roberto $
2+
** $Id: lparser.c,v 2.173 2017/12/18 12:33:54 roberto Exp roberto $
33
** Lua Parser
44
** See Copyright Notice in lua.h
55
*/
@@ -1313,11 +1313,20 @@ static void repeatstat (LexState *ls, int line) {
13131313
}
13141314

13151315

1316-
static void exp1 (LexState *ls) {
1316+
/*
1317+
** Read an expression and generate code to put its results in next
1318+
** stack slot. Return true if expression is a constant integer and,
1319+
** if 'i' is not-zero, its value is equal to 'i'.
1320+
**
1321+
*/
1322+
static int exp1 (LexState *ls, int i) {
13171323
expdesc e;
1324+
int res;
13181325
expr(ls, &e);
1326+
res = luaK_isKint(&e) && (i == 0 || i == e.u.ival);
13191327
luaK_exp2nextreg(ls->fs, &e);
13201328
lua_assert(e.k == VNONRELOC);
1329+
return res;
13211330
}
13221331

13231332

@@ -1337,29 +1346,37 @@ static void fixforjump (FuncState *fs, int pc, int dest, int back) {
13371346
}
13381347

13391348

1340-
static void forbody (LexState *ls, int base, int line, int nvars, int isnum) {
1349+
/*
1350+
** Generate code for a 'for' loop. 'kind' can be zero (a common for
1351+
** loop), one (a basic for loop, with integer values and increment of
1352+
** 1), or two (a generic for loop).
1353+
*/
1354+
static void forbody (LexState *ls, int base, int line, int nvars, int kind) {
13411355
/* forbody -> DO block */
13421356
BlockCnt bl;
13431357
FuncState *fs = ls->fs;
13441358
int prep, endfor;
13451359
adjustlocalvars(ls, 3); /* control variables */
13461360
checknext(ls, TK_DO);
1347-
prep = isnum ? luaK_codeABx(fs, OP_FORPREP, base, 0) : luaK_jump(fs);
1361+
prep = (kind == 0) ? luaK_codeABx(fs, OP_FORPREP, base, 0)
1362+
: (kind == 1) ? luaK_codeABx(fs, OP_FORPREP1, base, 0)
1363+
: luaK_jump(fs);
13481364
enterblock(fs, &bl, 0); /* scope for declared variables */
13491365
adjustlocalvars(ls, nvars);
13501366
luaK_reserveregs(fs, nvars);
13511367
block(ls);
13521368
leaveblock(fs); /* end of scope for declared variables */
1353-
if (isnum) { /* numeric for? */
1354-
fixforjump(fs, prep, luaK_getlabel(fs), 0);
1355-
endfor = luaK_codeABx(fs, OP_FORLOOP, base, 0);
1356-
}
1357-
else { /* generic for */
1369+
if (kind == 2) { /* generic for? */
13581370
luaK_patchtohere(fs, prep);
13591371
luaK_codeABC(fs, OP_TFORCALL, base, 0, nvars);
13601372
luaK_fixline(fs, line);
13611373
endfor = luaK_codeABx(fs, OP_TFORLOOP, base + 2, 0);
13621374
}
1375+
else {
1376+
fixforjump(fs, prep, luaK_getlabel(fs), 0);
1377+
endfor = (kind == 0) ? luaK_codeABx(fs, OP_FORLOOP, base, 0)
1378+
: luaK_codeABx(fs, OP_FORLOOP1, base, 0);
1379+
}
13631380
fixforjump(fs, endfor, prep + 1, 1);
13641381
luaK_fixline(fs, line);
13651382
}
@@ -1369,21 +1386,25 @@ static void fornum (LexState *ls, TString *varname, int line) {
13691386
/* fornum -> NAME = exp,exp[,exp] forbody */
13701387
FuncState *fs = ls->fs;
13711388
int base = fs->freereg;
1389+
int basicfor = 1; /* true if it is a "basic" 'for' (integer + 1) */
13721390
new_localvarliteral(ls, "(for index)");
13731391
new_localvarliteral(ls, "(for limit)");
13741392
new_localvarliteral(ls, "(for step)");
13751393
new_localvar(ls, varname);
13761394
checknext(ls, '=');
1377-
exp1(ls); /* initial value */
1395+
if (!exp1(ls, 0)) /* initial value not an integer? */
1396+
basicfor = 0; /* not a basic 'for' */
13781397
checknext(ls, ',');
1379-
exp1(ls); /* limit */
1380-
if (testnext(ls, ','))
1381-
exp1(ls); /* optional step */
1398+
exp1(ls, 0); /* limit */
1399+
if (testnext(ls, ',')) {
1400+
if (!exp1(ls, 1)) /* optional step not 1? */
1401+
basicfor = 0; /* not a basic 'for' */
1402+
}
13821403
else { /* default step = 1 */
13831404
luaK_int(fs, fs->freereg, 1);
13841405
luaK_reserveregs(fs, 1);
13851406
}
1386-
forbody(ls, base, line, 1, 1);
1407+
forbody(ls, base, line, 1, basicfor);
13871408
}
13881409

13891410

@@ -1408,7 +1429,7 @@ static void forlist (LexState *ls, TString *indexname) {
14081429
line = ls->linenumber;
14091430
adjust_assign(ls, 3, explist(ls, &e), &e);
14101431
luaK_checkstack(fs, 3); /* extra space to call generator */
1411-
forbody(ls, base, line, nvars - 3, 0);
1432+
forbody(ls, base, line, nvars - 3, 2);
14121433
}
14131434

14141435

‎lvm.c‎

Lines changed: 27 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,5 @@
11
/*
2-
** $Id: lvm.c,v 2.324 2017/12/04 17:41:30 roberto Exp roberto $
2+
** $Id: lvm.c,v 2.326 2017/12/18 17:49:31 roberto Exp $
33
** Lua virtual machine
44
** See Copyright Notice in lua.h
55
*/
@@ -1564,6 +1564,32 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
15641564
}
15651565
return;
15661566
}
1567+
vmcase(OP_FORLOOP1) {
1568+
lua_Integer idx = intop(+, ivalue(vra), 1); /* increment index */
1569+
lua_Integer limit = ivalue(s2v(ra + 1));
1570+
if (idx <= limit) {
1571+
pc -= GETARG_Bx(i); /* jump back */
1572+
chgivalue(vra, idx); /* update internal index... */
1573+
setivalue(s2v(ra + 3), idx); /* ...and external index */
1574+
}
1575+
updatetrap(ci);
1576+
vmbreak;
1577+
}
1578+
vmcase(OP_FORPREP1) {
1579+
TValue *init = vra;
1580+
TValue *plimit = s2v(ra + 1);
1581+
lua_Integer ilimit, initv;
1582+
int stopnow;
1583+
if (!forlimit(plimit, &ilimit, 1, &stopnow)) {
1584+
savepc(L); /* for the error message */
1585+
luaG_runerror(L, "'for' limit must be a number");
1586+
}
1587+
initv = (stopnow ? 0 : ivalue(init));
1588+
setivalue(plimit, ilimit);
1589+
setivalue(init, intop(-, initv, 1));
1590+
pc += GETARG_Bx(i);
1591+
vmbreak;
1592+
}
15671593
vmcase(OP_FORLOOP) {
15681594
if (ttisinteger(vra)) { /* integer loop? */
15691595
lua_Integer step = ivalue(s2v(ra + 2));

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