[FFmpeg-devel] [PATCH] Make mmx2 dependent on mmx/ssse3 dependent on mmx2

Loren Merritt lorenm
Fri Mar 21 21:04:19 CET 2008

On Fri, 21 Mar 2008, M?ns Rullg?rd wrote:
> Panagiotis Issaris <takis.issaris at uhasselt.be> writes:
>> First of all, I'm not sure about this patch... The thing is, I had
>> expected the configure script to disable mmx2 and ssse3 too when
>> disabling mmx, which it currently doesn't do. But, that's just because
>> I'm not aware of any machines implementing mmx2 but not mmx. Anyway,
>> attached patch makes mmx2 dependent on mmx, likewise for ssse3 which
>> becomes dependent on mmx2. So, with the attached patch --disable-mmx
>> disables them all.
>> Index: configure
>> ===================================================================
>> --- configure	(revision 12527)
>> +++ configure	(working copy)
>> @@ -782,8 +784,8 @@
>>  iwmmxt_deps="armv4l"
>>  mmi_deps="mips"
>>  mmx_deps="x86"
>> -mmx2_deps="x86"
>> -ssse3_deps="x86"
>> +mmx2_deps="x86 mmx"
>> +ssse3_deps="x86 mmx2"
>>  vis_deps="sparc"
>>  # decoders / encoders
> I can imagine someone wishing to disable only mmx on an sse-capable
> machine to save some space.  If you want an option to disable all
> assembler optimisations, it should be called something else.

In that case, you want an option that disables only those functions that 
have an sse replacement.

Also what about --disable-sse1, sse2, sse3? I though just mmx and ssse3 
were ok because --disable-mmx disabled all x86 simd, and ssse3 was needed 
because it's a recent addition so some toolchains don't support it yet. 
But if you care about exactly which sets to disable...

--Loren Merritt

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