[FFmpeg-devel] [PATCH] x86/hevc_sao: make sao_band_filter work on x86_32

[James Almer]

On 08/02/15 3:41 PM, Christophe Gisquet wrote:
> Hi,
> 
> 2015-02-08 18:48 GMT+01:00 James Almer <jamrial at gmail.com>:
>>>> +    %assign MMSIZE mmsize
>>>
>>> Why do that? Not a big deal: it's only for my education, if there's
>>> something I'm missing.
>>
>> For width 48, the COMPUTE macro is last run after an INIT_XMM cpuname, so mmsize becomes
>> 16 and in the avx2 version the instructions would access the wrong data in stack.
>> Doing %assign MMSIZE mmsize at the beginning of the function and using it here makes sure
>> it's always 32 in avx2.
>> sse2 is unaffected by this, of course.
>>
>> And the reason I'm using INIT_XMM in the middle of the function for the avx2 width 48 case
>> is because i couldn't find a nice and clean way to use the xm* reg aliases with the COMPUTE
>> macros.
> 
> OK. Strange that it still compiled fine on Win32 here, but I haven't
> looked at the code generated, and I can't run the avx2 version.
> 
>>>> +cglobal hevc_sao_band_filter_%1_8, 6, 6, 15, 8*mmsize*ARCH_X86_32, dst, src, dststride, srcstride, offset, left
>>>>      HEVC_SAO_BAND_FILTER_INIT 8
>>>
>>> Why do you need room for 8 regs, and not 7?
>>
>> Remnant from before i realized i could keep m7 untouched. I'll change it.
> 
> If that's the only change, then, unless someone complains, just push
> that version.

Pushed, thanks.