[FFmpeg-devel] [PATCH] PPC runtime altivec detection via mfspr

Guillaume POIRIER poirierg
Thu Nov 15 13:23:33 CET 2007


On Nov 15, 2007 11:51 AM, Reimar D?ffinger
<Reimar.Doeffinger at stud.uni-karlsruhe.de> wrote:
> Hello,
> attached patch adds altivec detection via the mfspr.
> Unfortunately, there is no way to detect if mfspr is available,
> neither is there a configure flag to manually enable/disable runtime
> cpudetection.
> So as a (temporary) hack I made the code conditional on MPlayer's
> I agree this is ugly, and for ffmpeg we could just as well put it under
> #elif 0.
> I just think it might be nice to have this code in because it seems e.g.
> Debian could use it without any problems, whereas on my test system it
> would always crash.
> Of course, if someone wrote a proper ffmpeg configure part for it that
> would be nice as well...
> Opinions?

Runtime CPU detection is under Linux only right? I guess it's quite
implicit, since on OSX, the OS provides an syscall (or smth like that)
for AltiVec support detection...

Other than that, I don't have an opinion regarding your patch. I just
regret that it's required to do some hacks to detect PPC CPU features,
when on x86, the same thing is very simple.

A soldier will fight long and hard for a bit of colored ribbon.
 -- Napoleon Bonaparte

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