[Ffmpeg-devel] [PATCH] SSE counterpart of ff_imdct_calc_3dn2
Loren Merritt
lorenm
Thu Aug 24 19:11:48 CEST 2006
On Thu, 24 Aug 2006, Luca Barbato wrote:
> Zuxy Meng wrote:
>
>> + z += n8;
>
>[...]
>> + for(k = 0; k < n8; k += 2) {
>[...]
>> + asm (
>> + "movaps %4, %%xmm0 \n\t" // xmm0 = 0 1 2 3
>> + "movaps %5, %%xmm1 \n\t" // xmm1 = 4 5 6 7
>[...]
>> + :"m"(z[k]), "m"(z[-2 - k])
>
> I'm missing something or it could be unaligned?
> z is 8 byte not 16.
The array index is even. In order for n8 to be odd you'd need an 8 element
fft. Nothing in ffmpeg does one that small, and the simd code would
break for more reasons than just alignment.
--Loren Merritt
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