[FFmpeg-devel] [PATCH + RFC] Faster ff_celp_lp_synthesis_filterf() (and failed SSE SIMD version)

Vitor Sessak vitor1001
Mon Dec 14 22:21:47 CET 2009


Vitor Sessak wrote:
> Michael Niedermayer wrote:
>> On Sun, Dec 13, 2009 at 08:55:08PM +0100, Vitor Sessak wrote:
>> [...]
>>> +            old_out3 = old_out2;
>>> +            old_out2 = old_out1;
>>> +            old_out1 = old_out0;
>>> +            old_out0 = out[-i-1];
>>> +
>>> +            val = filter_coeffs[i];
>>> +
>>> +            out0 -= val * old_out0;
>>> +            out1 -= val * old_out1;
>>> +            out2 -= val * old_out2;
>>> +            out3 -= val * old_out3;
>>
>> old_out3 = out[-i-1];
>>
>> val = filter_coeffs[i];
>> out0 -= val * old_out3;
>> out1 -= val * old_out0;
>> out2 -= val * old_out1;
>> out3 -= val * old_out2;
>>
>> and similarly you can get rid of the other copies if you unroll it more
> 
> Indeed, done. New patch attached.
> 
> BTW, in my SSE code, there was a line of code missing:
> 
>> DECLARE_ASM_CONST(16, uint32_t, mask[4]) = {0xFFFFFFFF, 0xFFFFFFFF,
>>                                             0xFFFFFFFF, 0x00000000};
>>

Err, this time without reinventing FFSWAP()...

-Vitor
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