[PATCH] iWMMXt support was Re: [Ffmpeg-devel] iWMMXt support

[Michael Niedermayer]

Hi

On Thu, Mar 15, 2007 at 10:52:30AM +0100, Guillaume Poirier wrote:
> Hi,
> 
> Reimar D?ffinger wrote:
> > Hello,
> > On Thu, Mar 15, 2007 at 12:10:56AM +0100, Guillaume POIRIER wrote:
> > 
> >>Couldn't be done in the same way as we do Altivec support detection on 
> >>Linux?
> >>
> >>The idea is simple: install a signal handler for SIGILL, try to
> >>exectute an iWMMXt instruction, and if it triggers a SIGILL, then that
> >>means that no support is there, otherwise, iWMMXt is available.
> > 
> > 
> > And that one is still broken. It sent a patch to make it restore at
> > least the signal handler again to its original value, but it was
> > suggested to remove the whole hack instead.
> 
> Maybe it's a hack, but I'd like to see someone coming up with a proper
> way to test for Altivec support. I mean, there's gotta be a proper
> way, it's just that Google isn't that informative :-(

proper way is leaving it to the user application, possibly with a function
which the application could call explicitly and which says in its doxygen
comment that it might install a signal handler to test cpu capabilities


[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Everything should be made as simple as possible, but not simpler.
-- Albert Einstein
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