[Ffmpeg-devel] weird snow segfaults on amd64

Aurelien Jacobs aurel
Mon Apr 18 13:25:18 CEST 2005


On Mon, 18 Apr 2005 03:23:16 +0200
Michael Niedermayer <michaelni at gmx.at> wrote:

> Hi
> 
> On Monday 18 April 2005 03:08, Aurelien Jacobs wrote:
> > On Sun, 17 Apr 2005 16:21:40 +0200
> >
> > Michael Niedermayer <michaelni at gmx.at> wrote:
> > > btw, maybe try to disable the START/STOP_TIMER macros (a trivial
> > > #if ... ->  #if 0 change in common.h), i think gcc misscompiles
> > > them on AMD64
> >
> > Right ! Disabling START/STOP_TIMER fix the segfault on AMD64.
> > I investigated a bit further and it seems that the "=A" constraint
> > don't work properly on AMD64. Maybe rdtsc modify the full rax/rdx
> > and "=A" only backup/restore eax/edx or something like that ?
> > So I've written an AMD64 specific rdtsc() implementation. I know
> > it's not very nice but I can't come with a cleaner solution.
> > Should I apply it ?
> 
> yes

done.

Aurel





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