[FFmpeg-devel] [PATCH] Assign unique values to AV_CPU_FLAG_IWMMXT and AV_CPU_FLAG_ALTIVEC.

[Reimar Döffinger]

On Wed, Sep 08, 2010 at 11:41:54AM -0400, Ronald S. Bultje wrote:
> Hi,
> 
> On Wed, Sep 8, 2010 at 11:32 AM, Janne Grunau <janne-ffmpeg at jannau.net> wrote:
> > On Wed, Sep 08, 2010 at 09:55:04AM -0400, Ronald S. Bultje wrote:
> >> On Wed, Sep 8, 2010 at 7:44 AM, Janne Grunau <janne-ffmpeg at jannau.net> wrote:
> >> > if (mm_flags && FF_MM_MMX)
> >> > ? ? ? ?cpuflags |= SWS_CPU_CAPS_MMX;
> >> > if (mm_flags && FF_MM_ALTIVEC)
> >> > ? ? ? ?cpuflags |= SWS_CPU_CAPS_ALTIVEC;
> >> >
> >> > had strange results since SWS_CPU_CAPS_MMX != SWS_CPU_CAPS_ALTIVEC.
> >> > Easily solveable with adding HAVE_(MMX|ALTIVEC) && to the ifs.
> >>
> >> This should all be under ARCH_PPC or HAVE_MMX and similar. x86-family
> >> CPUs supporting altivec don't exist.
> >
> > yes, the working code has 'if (HAVE_ALTIVEC && mm_flags & FF_MM_ALTIVEC)'
> 
> Excellent. Stefano, do you think it makes sense to document these
> flags a little so that it's obvious that altivec can only be used
> conditionally based on HAVE_ALTIVEC, x86-flags based on HAVE_MMX etc.?
> This should really be documented to prevent this from coming up again
> or causing issues for people.

Defining them to 0 for the "wrong" architectures like Michael suggested
might be the nicer solution...