[FFmpeg-devel] [RFC] clobbers for XMM registers

Måns Rullgård mans
Tue Sep 28 17:57:32 CEST 2010


Ramiro Polla <ramiro.polla at gmail.com> writes:

> On Tue, Sep 28, 2010 at 11:34 AM, Michael Niedermayer <michaelni at gmx.at> wrote:
>> On Tue, Sep 28, 2010 at 10:32:41AM -0400, Ronald S. Bultje wrote:
>>> On Tue, Sep 28, 2010 at 10:19 AM, Michael Niedermayer <michaelni at gmx.at> wrote:
>>> > On Tue, Sep 28, 2010 at 10:15:29AM -0400, Ronald S. Bultje wrote:
>>> >> On Tue, Sep 28, 2010 at 10:09 AM, Michael Niedermayer <michaelni at gmx.at> wrote:
>>> >> > On Tue, Sep 28, 2010 at 09:36:40AM -0400, Ronald S. Bultje wrote:
>>> >> >> On Tue, Sep 28, 2010 at 8:34 AM, Michael Niedermayer <michaelni at gmx.at> wrote:
>>> >> >> > you want to execute code from vp3dsp_sse2.c on a pre SSE cpu?
>>> >> >>
>>> >> >> All _sse2 files are templates files that are included in dsputil_mmx.c
>>> >> >> or similar.
>>> >> >
>>> >> > we could add the flags to dsputil_mmx then or split the file.
>>> >>
>>> >> Before splitting, can someone first confirm that -msse actually fixes it?
>>> >
>>> > i cant confirm that it fixes it as i dont have an affected platform but
>>> > it definitly fails here with an identical looking error if i pass -mno-sse
>>>
>>> I would feel safer if someone on BSD/Win of one of the affected FATE
>>> platforms could confirm that this fixes the issue.
>>
>> of course
>
> $ cat clobber.c
> void foo(void)
> {
>     asm("nop\n\t"::: "xmm0");
> }
> $ i686-mingw32-gcc-4.4 -o /dev/null -c clobber.c
> clobber.c: In function 'foo':
> clobber.c:3: error: unknown register name 'xmm0' in 'asm'
> $ i686-mingw32-gcc-4.4 -o /dev/null -c clobber.c -msse
> $

Why is this different on Windows?

-- 
M?ns Rullg?rd
mans at mansr.com



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