[Ffmpeg-devel] [BUG] Compilation failure when using --disable-opts

Måns Rullgård mans
Wed Mar 14 23:16:59 CET 2007


Panagiotis Issaris <takis at issaris.org> writes:

> Hi M?ns,
>
> M?ns Rullg?rd schreef:
>> 
>> Isn't there already some x86 section this could be added to?  
> I could add it here... but that doesn't look good to me for some
> reason... it seems a bit ugly to do these tests while output is already
> being generated.
>
> 1793 echo "big-endian                $bigendian"
> 1794 if test $arch = "x86_32" -o $arch = "x86_64"; then
> 1795     echo "MMX enabled               $mmx"
> 1796     echo "CMOV enabled              $cmov"
> 1797     echo "CMOV is fast              $fast_cmov"
> 1798 fi
> 1799 if test $arch = "armv4l"; then

No, not there.

> And there's this spot, but that is even further near the end...
> 1909 # special cases
> 1910 case "$arch" in
> 1911     x86_32|x86_64)
> 1912         echo "TARGET_ARCH_X86=yes" >> config.mak
> 1913         echo "#define ARCH_X86 1" >> $TMPH
> 1914         ;;
> 1915     powerpc)

And not there either.

> But if you prefer to have the tests in one of those, I'll change the patch.

It certainly doesn't belong in any of those.  I was thinking there
should be some section dealing with mmx and such.

>> And are you certain that this is correct for x86_64?  Is the check
>> even needed there, what with all the extra registers?
> Actually, I do not really know... I figured that because x86_64 is
> backwards compatible

The instruction set is compatible, meaning that everything that works
on 32-bit x86 still works on a 64-bit chip.  Things that don't work on
32-bit chips might still be possible.  8 extra registers come to
mind...

> the registers are still there and the tests should still work. In the
> worst case the tests would be unnecessary ofcourse... Prefer to remove
> it and only add it when someone figures out how this works on x86_64?

I don't think this is very urgent, so I'd rather wait a day for
someone with the knowledge to shed some light.

-- 
M?ns Rullg?rd
mans at mansr.com




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