On Sat, 28 Jun 2008, Marius Strobl wrote:
On Sat, Jun 28, 2008 at 12:09:13PM +1000, Bruce Evans wrote:
On Sat, 28 Jun 2008, Marius Strobl wrote:
I think it still only works by chance.
[volatile]
Besides I don't think using "__volatile" for this is
that wrong, given that the sparc64 code generated by using "cc"
and "__volatile" is nearly identical and given that at least i386
relies on "__volatile" telling GCC that the inline assembler uses
the condition codes since quite some time. So the condition codes
are probably part of what GCC treats as "important side-effects".
No, the comments in the i386 version are rotted bits left over from
old failing attempts to fix this problem.
So by now you are saying that using "__volatile" in this case
is the wrong solution and that using "cc" is a style bug. How
am I supposed to tell the compiler that the inline assembler
alters the condition codes then, which it apparently needs to
know as it at shown to otherwise generate broken code even
when using a single __asm() for the istructions.
Using volatile is wrong in this and most cases.
Use "cc" when it isn't a style bug :-). I guess this is on some CPUs
including sparc64 now, and in all new asms on i386.
Bruce
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