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simpler implementation of for loops

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This commit is contained in:
Roberto Ierusalimschy
2001-01-29 13:26:40 -02:00
parent caf01b5bfa
commit 3b6f8bfbe6
4 changed files with 29 additions and 29 deletions
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38
lvm.c
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@@ -1,5 +1,5 @@
/*
** $Id: lvm.c,v 1.158 2001/01/26 18:43:22 roberto Exp roberto $
** $Id: lvm.c,v 1.159 2001/01/29 13:02:20 roberto Exp roberto $
** Lua virtual machine
** See Copyright Notice in lua.h
*/
@@ -330,7 +330,7 @@ static void adjust_varargs (lua_State *L, StkId base, int nfixargs) {
#define dojump(pc, i) { int d = GETARG_S(i); pc += d; }
#define dojump(pc, i) ((pc) += GETARG_S(i))
/*
** Executes the given Lua function. Parameters are between [base,top).
@@ -615,19 +615,15 @@ StkId luaV_execute (lua_State *L, const Closure *cl, StkId base) {
break;
}
case OP_FORPREP: {
int jmp = GETARG_S(i);
if (tonumber(top-1))
luaD_error(L, "`for' step must be a number");
if (tonumber(top-2))
luaD_error(L, "`for' limit must be a number");
if (tonumber(top-3))
luaD_error(L, "`for' initial value must be a number");
if (nvalue(top-1) > 0 ?
nvalue(top-3) > nvalue(top-2) :
nvalue(top-3) < nvalue(top-2)) { /* `empty' loop? */
top -= 3; /* remove control variables */
dojump(pc, i); /* jump to loop end */
}
break;
pc += -jmp; /* "jump" to loop end (delta is negated here) */
goto forloop; /* do not increment index */
}
case OP_FORLOOP: {
lua_assert(ttype(top-1) == LUA_TNUMBER);
@@ -635,6 +631,7 @@ StkId luaV_execute (lua_State *L, const Closure *cl, StkId base) {
if (ttype(top-3) != LUA_TNUMBER)
luaD_error(L, "`for' index must be a number");
nvalue(top-3) += nvalue(top-1); /* increment index */
forloop:
if (nvalue(top-1) > 0 ?
nvalue(top-3) > nvalue(top-2) :
nvalue(top-3) < nvalue(top-2))
@@ -644,24 +641,15 @@ StkId luaV_execute (lua_State *L, const Closure *cl, StkId base) {
break;
}
case OP_LFORPREP: {
int n;
Hash *t;
int jmp = GETARG_S(i);
if (ttype(top-1) != LUA_TTABLE)
luaD_error(L, "`for' table must be a table");
t = hvalue(top-1);
n = luaH_nexti(t, -1);
if (n == -1) { /* `empty' loop? */
top--; /* remove table */
dojump(pc, i); /* jump to loop end */
}
else {
Node *node = node(t, n);
top += 3; /* index,key,value */
setnvalue(top-3, n); /* index */
setobj(top-2, key(node));
setobj(top-1, val(node));
}
break;
top += 3; /* index,key,value */
setnvalue(top-3, -1); /* initial index */
setnilvalue(top-2);
setnilvalue(top-1);
pc += -jmp; /* "jump" to loop end (delta is negated here) */
/* go through */
}
case OP_LFORLOOP: {
Hash *t = hvalue(top-4);