[FFmpeg-devel] [PATCH] avcodec/vp3data: combine eob_run_base and eob_run_get_bits tables

[Peter Ross]

On Sun, May 26, 2019 at 09:27:55PM +0200, Reimar Döffinger wrote:
> On Sat, May 25, 2019 at 12:04:49PM +1000, Peter Ross wrote:
> > ---
> > This provides a small readability improvement.
> > I observe no performance change on x86_64 or arm6.
> 
> Looks good to me, but probably the maintainer should decide.
> I guess I'd be very mildly curious to know if the asm code
> the compiler generates looks (slightly) better with this change
> as I expect, but if I'm honest it's not really relevant.

ok.

x86_64:

-before patch
+after patch

+       leaq    eob_run_table(%rip), %rcx
        movslq  %edx, %rdx
-       leaq    eob_run_base(%rip), %rcx
-       movzbl  (%rcx,%rdx), %edi
+       movzbl  (%rcx,%rdx,2), %edi
 .LVL540:
-       leaq    eob_run_get_bits(%rip), %rcx
-       movzbl  (%rcx,%rdx), %edx
+       movzbl  1(%rcx,%rdx,2), %edx

-- Peter
(A907 E02F A6E5 0CD2 34CD 20D2 6760 79C5 AC40 DD6B)
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