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5l: two stack split bugs in one day

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An ARM expert could probably phrase the
comparison in fewer instructions, but this works.

R=ken2
CC=golang-dev
https://golang.org/cl/2620041
This commit is contained in:
Russ Cox 2010-10-20 18:11:53 -04:00
parent 10b53867e8
commit 231fcea7e6
1 changed files with 27 additions and 9 deletions
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36
src/cmd/5l/noop.c
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@ -37,6 +37,7 @@
enum
{
StackBig = 4096,
StackSmall = 128,
};
static Sym* sym_div;
@ -296,7 +297,7 @@ noops(void)
// TODO(kaib): add more trampolines
// TODO(kaib): put stackguard in register
// TODO(kaib): add support for -K and underflow detection
// MOVW g_stackguard(g), R1
p = appendp(p);
p->as = AMOVW;
@ -304,14 +305,31 @@ noops(void)
p->from.reg = REGG;
p->to.type = D_REG;
p->to.reg = 1;
// CMP R1, $-autosize(SP)
p = appendp(p);
p->as = ACMP;
p->from.type = D_REG;
p->from.reg = 1;
p->from.offset = -autosize;
p->reg = REGSP;
if(autosize < StackSmall) {
// CMP R1, SP
p = appendp(p);
p->as = ACMP;
p->from.type = D_REG;
p->from.reg = 1;
p->reg = REGSP;
} else {
// MOVW $-autosize(SP), R2
// CMP R1, R2
p = appendp(p);
p->as = AMOVW;
p->from.type = D_CONST;
p->from.reg = REGSP;
p->from.offset = -autosize;
p->to.type = D_REG;
p->to.reg = 2;
p = appendp(p);
p->as = ACMP;
p->from.type = D_REG;
p->from.reg = 1;
p->reg = 2;
}
// MOVW.LO $autosize, R1
p = appendp(p);