| Message ID | b718bb0c9383b4b332eb943324a3e4568437c1e1.1558749041.git.pross@xvid.org |
|---|---|
| State | Accepted |
| Commit | b6ca032adebe05573d9fe9c3a2625240f55b33b0 |
| Headers | show |
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.
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)
diff --git a/libavcodec/vp3.c b/libavcodec/vp3.c index b248c90413..63f60c9109 100644 --- a/libavcodec/vp3.c +++ b/libavcodec/vp3.c @@ -988,9 +988,9 @@ static int unpack_vlcs(Vp3DecodeContext *s, GetBitContext *gb, token = get_vlc2(gb, vlc_table, 11, 3); /* use the token to get a zero run, a coefficient, and an eob run */ if ((unsigned) token <= 6U) { - eob_run = eob_run_base[token]; - if (eob_run_get_bits[token]) - eob_run += get_bits(gb, eob_run_get_bits[token]); + eob_run = eob_run_table[token].base; + if (eob_run_table[token].bits) + eob_run += get_bits(gb, eob_run_table[token].bits); if (!eob_run) eob_run = INT_MAX; diff --git a/libavcodec/vp3data.h b/libavcodec/vp3data.h index c82b1b3a86..d520a10c76 100644 --- a/libavcodec/vp3data.h +++ b/libavcodec/vp3data.h @@ -198,11 +198,10 @@ static const int8_t fixed_motion_vector_table[64] = { }; /* only tokens 0..6 indicate eob runs */ -static const uint8_t eob_run_base[7] = { - 1, 2, 3, 4, 8, 16, 0 -}; -static const uint8_t eob_run_get_bits[7] = { - 0, 0, 0, 2, 3, 4, 12 +static const struct { + uint8_t base, bits; +} eob_run_table[7] = { + {1, 0}, {2, 0}, {3, 0}, {4, 2}, {8, 3}, {16, 4}, {0, 12} }; static const uint8_t zero_run_base[32] = {