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

Panagiotis Issaris takis
Wed Mar 14 23:26:38 CET 2007

M?ns Rullg?rd schreef:
> Panagiotis Issaris <takis at issaris.org> writes:
>> M?ns Rullg?rd schreef:
>>> Isn't there already some x86 section this could be added to?  
> 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.
The only other area in which I noticed a $arch "x86_32" compare was this
1242 # compute MMX state
1243 if test $mmx = "default"; then
1244     if test $arch = "x86_32" -o $arch = "x86_64"; then
1245         mmx="yes"
1246     else
1247         mmx="no"
1248     fi
1249 fi

Which I dismissed immediately, because the test is inside the
$mmx==default conditional.

>>> 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...
Sure, but I wouldn't know if ebp specifically wasn't still being used
for the base pointer :) Of course the original problem (in cabac.h)
would be gone with those extra registers...

>> 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.
Sure. Although I wonder: Doesn't anybody in here use a debugger? Aren't
you annoyed by the jumping around because of reorderings caused by the
compilers' optimizations?

With friendly regards,

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