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

Guillaume POIRIER poirierg
Sat Dec 27 12:41:37 CET 2008


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
  movd [
  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

Only a very small fraction of our DNA does anything; the rest is all
comments and ifdefs.

Bill Cosby  - "Human beings are the only creatures on earth that allow
their children to come back home."

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