[FFmpeg-devel] [PATCH 4/4] avfilter/vf_v360: x86 SIMD for interpolations

[James Almer]

On 9/4/2019 5:47 PM, Henrik Gramner wrote:
> On Wed, Sep 4, 2019 at 10:01 PM James Almer <jamrial at gmail.com> wrote:
>> On 9/4/2019 4:28 PM, Paul B Mahol wrote:
>>> +        vpmulld          m3, m1, m0
>>> +        vpaddd           m1, m3, m2
>>
>> pmulld m1, m0
>> paddd  m1, m2
> 
> Could use pmaddwd instead as well, it's faster than pmulld on pretty
> much every CPU.
> 
>>> +        mova             m2, m4
>>
>> Pointless mova. Just use m4 in the vpgatherdd below.
> 
> No, it's required. Gathers overwrite the mask register.

Ah, my bad.

> 
>>> +        vpgatherdd       m5, [srcq + m1], m2
>>> +        vextracti128    xm3, m5, 1
>>> +        vpshufb          m1, m5, m6
>>> +        vpshufb          m2, m3, m6
>>
>> You could make these two pshufb use xmm regs, since you don't care
>> what's in the upper 128 bits.
> 
> Or a single ymm pshufb before the vectracti128.