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runtime: save 8 stack bytes in timediv on arm.

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Operations on int64 are very stack consuming with 5c.
Fixes netbsd/arm build.

Before: TEXT    runtime.timediv+0(SB),7,$52-16
After:  TEXT    runtime.timediv+0(SB),7,$44-16

The stack usage is unchanged on 386:
        TEXT    runtime.timediv+0(SB),7,$8-16

R=golang-dev, dvyukov, bradfitz
CC=golang-dev
https://golang.org/cl/12182044
This commit is contained in:
Rémy Oudompheng 2013-07-31 23:37:23 +02:00
parent 727901410a
commit a05237f20a
1 changed files with 5 additions and 5 deletions
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10
src/pkg/runtime/runtime.c
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@ -421,16 +421,16 @@ runtime·timediv(int64 v, int32 div, int32 *rem)
{
int32 res, bit;
if(v >= div*0x7fffffffLL) {
if(v >= (int64)div*0x7fffffffLL) {
if(rem != nil)
*rem = 0;
return 0x7fffffff;
}
res = 0;
for(bit = 0x40000000; bit != 0; bit >>= 1) {
if(v >= (int64)bit*div) {
v = v - (int64)bit*div;
res += bit;
for(bit = 30; bit >= 0; bit--) {
if(v >= ((int64)div<<bit)) {
v = v - ((int64)div<<bit);
res += 1<<bit;
}
}
if(rem != nil)