Re: [FFmpeg-devel] [PATCH v4 1/2][GSoC 2024] libavcodec/x86/vvc: Add AVX2 DMVR SAD functions for VVC

["Ronald S. Bultje" <rsbultje@gmail.com>]

Hi,

This is mostly good, the following is tiny nitpicks.

On Sun, May 19, 2024 at 8:46 PM Stone Chen <chen.stonechen@gmail.com> wrote:

> +%macro INIT_OFFSET 6 ; src1, src2, dxq, dyq, off1, off2
>

The macro is only used once, so you could inline it in the calling function.

>
> +    imul            %5, 128
> +    imul            %6, 128
>

I believe shl is typically preferred over imul for powers of two.


> +    add             %5, 2
> +    add             %6, 2
>

And these can be integrated as a constant offset in the lea below (lea %1,
[%1 + %5 * 2 + 2 * 2], same for %2).


> +    add             %5, %3
> +    sub             %6, %3
> +
> +    lea             %1, [%1 + %5 * 2]
> +    lea             %2, [%2 + %6 * 2]

[..]

> +cglobal vvc_sad, 6, 11, 5, src1, src2, dx, dy, block_w, block_h, off1,
> off2, row_idx, dx2, dy2
> +    movsxd           dx2q, dxd
> +    movsxd           dy2q, dyd
>

If you change the argument type from int to intptr_t, this is not necessary
anymore.


> +    vvc_sad_16_128:
> +        .loop_height:
> +        mov         off1q, src1q
> +        mov         off2q, src2q
> +        mov      row_idxd, block_wd
> +        sar      row_idxd, 4
>

You could right-shift block_wd by 4 outside the loop (before .loop_height).

Ronald
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