[FFmpeg-devel] [PATCH] Remove global mm_flags variable

Michael Niedermayer michaelni
Tue Aug 24 21:44:55 CEST 2010

On Tue, Aug 24, 2010 at 10:39:30PM +0300, Ivan Kalvachev wrote:
> On 8/24/10, Mans Rullgard <mans at mansr.com> wrote:
> > -
> > -#define emms_c() \
> > -{\
> > -    if (mm_flags & FF_MM_MMX)\
> > -        emms();\
> > -}
> > +#define emms_c() emms()
> Michael, are you really OK with that change?
> The result would be illegal instruction on all pre-MMX CPUs.

who still uses these?
and how much pre mmx x86 asm do we have? and how much faster is
that on pre mmx cpus?

and dont forget disabling asm disables emms and thus this issue
also being able to use mmx without conditionals should allow some
speedups if we dont already use that somewhere, i remember it being
discussed ...


Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Many things microsoft did are stupid, but not doing something just because
microsoft did it is even more stupid. If everything ms did were stupid they
would be bankrupt already.
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