[FFmpeg-devel] [PATCH] Altivec version of new split-radix FFT4.

[Guillaume POIRIER]

Hello,

On Sat, Dec 27, 2008 at 11:32 AM, Luca Barbato <lu_zero at gentoo.org> wrote:
> Guillaume Poirier wrote:
>> Hello Folks, and happy holidays!
>> I've written Altivec version of the new split-radix FFT4.
>
> Great! =)
>
>> I'll hopefully apply it  once I have an Altivec implementation of FFT8
>> ready too.
>>
>> I hope you guys don't mind being used as my backup system, right? ;-)
>
> Absolutely not ^^;

:-)


>> Cheers!
>
> btw the fft4/fft8 are applied always on aligned memory?

I'm just trusting that's already done for x86:

 grep mov libavcodec/x86/fft_mmx.asm | cut -c 3-10 | sort | uniq
%1 mova
  mova
  movd [
  movq
  mov r2

As you can see (maybe), there's no instruction for unaligned memory
access in the implementation. I assume it's correct since an unaligned
memory access with an instruction that does aligned memory read leads
to SIGILL.

Guillaume
-- 
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comments and ifdefs.

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