You are right.
My compiler also produces this absolutely decent code when not
specifying the variables as "volatile".
With "volatile" the code is a lot worse, I don't understand this, as the
"normal" code not only fulfills what is necessary to volatile but even
is "thread-atomic", as a thread switch does not do an interrupt within a
single instruction, not even with the Fido that provides _hardware_ threads.
Thanks a lot for discussing this with me.
-Michael
On 08/03/2012 03:34 PM, Luis Alves wrote:
Hi Michael,
Here is the result (gcc version is 4.2.4):
C test code used:
int xx, xy;
int yy, yx;
int zz;
int main(void)
{
xx |= 0x80;
xy |= 0x80000000;
if (zz & 0x4000)
yy=yx;
return 0;
}
[...]
main:
link.w %fp,#0
or.w #128,xx+2
bset #7,xy
btst #6,zz+2
jbeq .L2
move.l yx,yy
.L2:
clr.l %d0
unlk %fp
rts
[...]
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