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

[Michael Niedermayer]

On Wed, Sep 08, 2010 at 11:56:30AM +0200, Stefano Sabatini wrote:
> On date Sunday 2010-09-05 21:51:57 -0400, Ronald S. Bultje encoded:
> > Hi,
> > 
> > On Sun, Sep 5, 2010 at 8:04 PM, Stefano Sabatini
> > <stefano.sabatini-lala at poste.it> wrote:
> > > ---
> > > ?libavutil/cpu.h | ? ?4 ++--
> > > ?1 files changed, 2 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/libavutil/cpu.h b/libavutil/cpu.h
> > > index 644df3e..7ec52c8 100644
> > > --- a/libavutil/cpu.h
> > > +++ b/libavutil/cpu.h
> > > @@ -38,7 +38,7 @@
> > > ?#define AV_CPU_FLAG_SSSE3 ? ? ? ?0x0080 ///< Conroe SSSE3 functions
> > > ?#define AV_CPU_FLAG_SSE4 ? ? ? ? 0x0100 ///< Penryn SSE4.1 functions
> > > ?#define AV_CPU_FLAG_SSE42 ? ? ? ?0x0200 ///< Nehalem SSE4.2 functions
> > > -#define AV_CPU_FLAG_IWMMXT ? ? ? 0x0100 ///< XScale IWMMXT
> > > -#define AV_CPU_FLAG_ALTIVEC ? ? ?0x0001 ///< standard
> > > +#define AV_CPU_FLAG_IWMMXT ? ? ? 0x0400 ///< XScale IWMMXT
> > > +#define AV_CPU_FLAG_ALTIVEC ? ? ?0x0800 ///< Altivec
> > 
> > I don't think this is a good idea, as previously said.
> > 
> > Every use of AV_CPU_FLAG_ALTIVEC currently is, and should be, under
> > HAVE_ALTIVEC and every use of AV_CPU_FLAG_SSE*/MMX*/3DNOW/etc should
> > be under HAVE_MMX, since these are all exclusive. A real-life CPU will
> > never support both altivec and SSSE3.
> > 
> > Since this doesn't solve a problem and actually adds a problem of
> > having only 32 flags for all CPU extensions out there on all archs,
> > which is rather limiting given the amount of new extensions Intel and
> > Arm come up with every few months. Therefore, I'd rather not see this
> > committed.
> 
> I don't have a strong opinion so I can easily drop this patch, but
> having the same flag with different meanings is intrinsically messy,

> and I remember an user complaining about that for some reason.

thats a bad argument independant of what is discussed
or in other words if you dont remember the reasoning it really isnt helpfull

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

Democracy is the form of government in which you can choose your dictator
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