[FFmpeg-cvslog] r28500 - trunk/libswscale/swscale-example.c

[Michael Niedermayer]

On Mon, Feb 09, 2009 at 10:48:12PM +0100, Aurelien Jacobs wrote:
> Ivan Kalvachev wrote:
> 
> > On 2/9/09, Diego Biurrun <diego at biurrun.de> wrote:
> > > On Mon, Feb 09, 2009 at 08:13:55PM +0000, M?ns Rullg?rd wrote:
> > >> Diego Biurrun <diego at biurrun.de> writes:
> > >>
> > >> > On Mon, Feb 09, 2009 at 08:53:27PM +0100, Michael Niedermayer wrote:
> > >> >> On Mon, Feb 09, 2009 at 07:04:19PM +0100, diego wrote:
> > >> >> >
> > >> >> > Log:
> > >> >> > Add config.h #include for ARCH_X86 definition.
> > >> >>
> > >> >> config.h is not a public header there is no way how swscale-example
> > >> >> could
> > >> >> include it.
> > >> >> Please keep in mind this is a example on how people should use swscale
> > >> >> from
> > >> >> their code, you wouldnt want them to include our config.h would you?
> > >> >
> > >> > Unfortunately this example program was broken in multiple ways.  I fixed
> > >> > compilation so that at least 'make tests' can run, but yes, it still has
> > >> > issues.  It contains
> > >> >
> > >> >   #if ARCH_X86
> > >> >
> > >> > which implicitly relies on config.h being available.
> > >>
> > >> Then that should be fixed, not more breakage added.
> > >
> > > Do you have bright suggestions?  Is there a way to avoid the
> > >
> > > #if ARCH_X86
> > >     __asm__ volatile ("emms\n\t");
> > > #endif
> > 
> > This instruction clears the fpu registers after they have been used by mmx.
> > The real question is:
> > Is this really necessary? Does swscale leave the fpu registers in mmx
> > state to boost speed on K6?
> > From quick look in the template it looks like - no.
> > 
> > I guess this is ancient workaround for bug fixed long time ago.
> 
> It seems to be so.
> It indeed looks like swscale already does the appropriate emms, so
> they could be removed from swscale-example.c.
> Anyway, it don't seem reasonable to require calling apps to do an
> emms after calling swscale. So in case this emms in swscale-example.c
> is really required, I would consider this a bug in swscale.
> So what about attached patch ?

if you tested this with MMX/MMXEXT enabled and VERY important SSE* disabled
then ok

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

I know you won't believe me, but the highest form of Human Excellence is
to question oneself and others. -- Socrates
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 189 bytes
Desc: Digital signature
URL: <http://lists.mplayerhq.hu/pipermail/ffmpeg-cvslog/attachments/20090209/ca232e40/attachment.pgp>