[MPlayer-dev-eng] Altivec+GCC fix

Magnus Damm damm at opensource.se
Fri May 23 15:39:42 CEST 2003

Hi again,

> > > * libmpeg2/idct_altivec.c
> > >   Updated to version 1.19 from sourceforge
> > > * libmpeg2/motion_comp_altivec.c
> > >   Updated to version 1.12 from sourceforge
> However, these new files require altivec flags to be present to be able
> to compile. That is why I modified the Makefile instead of throwing in
> ifdefs in the source files. I though that it was easier to just have
> one file (makefile) that differs instead of modifying each c-file.
> To verify this I will download and test the libmpeg2 cvs
> on sourceforge, but I have no time today - maybe tomorrow.

After downloading the libmpeg2 snapshot and building it I realized that
libmpeg2-configure checks for altivec.h and enables altivec if that file
is present. And it is not possible to pass --enable/disable-altivec to 
force support on/off.

I can't see any makefiles/conditions that excludes idct_altivec.c and 
motion_comp_altivec.c from the build process if altivec support is missing,
and it is not possible for me to build these altivec-enabled files without 
passing the altivec-flags to gcc.

My conclusion is that it should be impossible to build libmpeg2 (on sf)
for powerpc with a gcc that has no support for altivec, but I have not
it since I have no compiler without altivec support.

mplayer has the nice feature --disable/enable-altivec so we need to 
conditionally choose the altivec sources depending on if altivec is 
enabled or disabled.

So I would say my patch is correct... =)

/ magnus

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