[x264-devel] Re: [Patch] x264 on ppc without altivec

[Guillaume POIRIER]

Hi,

On 3/4/07, Alexis Ballier <aballier at gentoo.org> wrote:
> Hi,
>
> while playing with a friend's efika I noticed that x264 assumed that a
> ppc has altivec. This results in nices "Illegal instructions" when you
> try to do anything.
>
> In fact, it could be autodetected (there is a nice "Fixme" in the
> autodetection routine for ppc ;) ), but the only detection methods I've
> found are from libmpeg2 (used in mplayer, ffmpeg), those try to execute
> altivec code while catching SIGILL. This method fails in x264, the
> signal is cought but SIGILL still kills x264, most likely because of
> threads.
>
> Please find enclosed a patch that allows to disable altivec at build
> time, defaulting to yes, in order to allow non altivec ppc users to use
> x264.

Here's what I think:
It should be possible to compile x264 without Altivec support, which
your patch addess, and it's good. Unless the others object, I'd like
to checkin a similar patch, that I'll post when it's ready.

Short of having a way to determine Altivec at runtime, I think it's a
good temporary solution, but in the end, x264 should just behave like
x86 does. It shouldn't be too hard.

Guillaume

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