[FFmpeg-devel] [PATCH] x86/dcadec: add ff_lfe_fir1_float_{sse3, avx}

[Christophe Gisquet]

Hi,

2016-02-22 22:43 GMT+01:00 James Almer <jamrial at gmail.com>:
> +.loop:
> +%if cpuflag(avx)
> +    cvtdq2ps  m4, [lfeq]
> +    shufps    m5, m4, m4, q0123
> +%elif cpuflag(sse2)
> +    movu      m4, [lfeq]
> +    cvtdq2ps  m4, m4
> +    pshufd    m5, m4, q0123
> +%endif
> +
> +.inner_loop:
> +%if ARCH_X86_64
> +    movaps    m6, [coeffq+cnt1q*4   ]
> +    movaps    m7, [coeffq+cnt1q*4+16]
> +    movaps    m8, [coeffq+cnt1q*4+32]
> +    movaps    m9, [coeffq+cnt1q*4+48]
> +    mulps     m0, m5, m6
> +    mulps     m1, m5, m7
> +    mulps     m2, m5, m8
> +    mulps     m3, m5, m9
> +%else
> +    movaps    m6, [coeffq+cnt1q*4   ]
> +    movaps    m7, [coeffq+cnt1q*4+16]
> +    mulps     m0, m5, m6
> +    mulps     m1, m5, m7
> +    mulps     m2, m5, [coeffq+cnt1q*4+32]
> +    mulps     m3, m5, [coeffq+cnt1q*4+48]
> +%endif

Is OOE the reason why you don't move the common code out of those
conditional blocks? Otherwise, it looks cleaner to me to do:
    movaps    m6, [coeffq+cnt1q*4   ]
    movaps    m7, [coeffq+cnt1q*4+16]
    mulps     m0, m3, m6
    mulps     m1, m3, m7
%if ARCH_X86_64
    movaps    m8, [coeffq+cnt1q*4+32]
    movaps    m9, [coeffq+cnt1q*4+48]
    mulps     m2, m5, m8
    mulps     m3, m5, m9
%else
    mulps     m2, m5, [coeffq+cnt1q*4+32]
    mulps     m3, m5, [coeffq+cnt1q*4+48]
%endif
and let OOE do its job.

Secondly, m5 is not reused afterwards, so maybe replace m5 by m3 for
all code up to this, and load something into m5 instead?

> +    haddps    m0, m1
> +    haddps    m2, m3
> +    haddps    m0, m2
> +    movaps [samplesq+cnt1q], m0

I suppose you've already looked at most arrangements that would help
doing fewer shuffles. And I don't see any obvious one either.

-- 
Christophe