[FFmpeg-devel] [PATCH] Add ppc/fmtconvert_ppc.c to fix compilation for PPC without Altivec.

Måns Rullgård mans
Sat Mar 5 13:42:57 CET 2011

"Ronald S. Bultje" <rsbultje at gmail.com> writes:

> Hi,
> On Sat, Mar 5, 2011 at 6:15 AM, Reimar D?ffinger
> <Reimar.Doeffinger at gmx.de> wrote:
>>> + ? ?int mm_flags = av_get_cpu_flags();
>>> +
>>> + ? ?if (mm_flags & AV_CPU_FLAG_ALTIVEC && HAVE_ALTIVEC) {
>> Is there any point to it? As far as I know as soon as
>> HAVE_ALTIVEC is set the code will crash on non-altivec
>> anyway so the av_get_cpu_flags is just confusing because
>> it pretends that something will work that does not at all.
> On some systems (e.g. Darwin, I believe) it returns valid flags. On
> others it's a dummy.

On Linux uses mfspr to check for altivec support if RUNTIME_CPUDETECT is
enabled.  However, with the compiler flags we use, the compiler is free
to use altivec code anywhere it pleases, so the detection is rather

M?ns Rullg?rd
mans at mansr.com

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