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lavc/aarch64: Add neon implementation for vsad16

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Provide optimized implementation of vsad16 function for arm64.

Performance comparison tests are shown below.
- vsad_0_c: 285.2
- vsad_0_neon: 39.5

Benchmarks and tests are run with checkasm tool on AWS Graviton 3.

Co-authored-by: Martin Storsjö <martin@martin.st>
Signed-off-by: Hubert Mazur <hum@semihalf.com>
Signed-off-by: Martin Storsjö <martin@martin.st>
This commit is contained in:
Hubert Mazur 2022-09-08 11:25:03 +02:00 committed by Martin Storsjö
parent a2fd553dd3
commit 200f5e578f
2 changed files with 70 additions and 0 deletions
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5
libavcodec/aarch64/me_cmp_init_aarch64.c
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@ -41,6 +41,9 @@ int sse8_neon(MpegEncContext *v, const uint8_t *pix1, const uint8_t *pix2,
int sse4_neon(MpegEncContext *v, const uint8_t *pix1, const uint8_t *pix2,
ptrdiff_t stride, int h);
int vsad16_neon(MpegEncContext *c, const uint8_t *s1, const uint8_t *s2,
ptrdiff_t stride, int h);
av_cold void ff_me_cmp_init_aarch64(MECmpContext *c, AVCodecContext *avctx)
{
int cpu_flags = av_get_cpu_flags();
@ -57,5 +60,7 @@ av_cold void ff_me_cmp_init_aarch64(MECmpContext *c, AVCodecContext *avctx)
c->sse[0] = sse16_neon;
c->sse[1] = sse8_neon;
c->sse[2] = sse4_neon;
c->vsad[0] = vsad16_neon;
}
}

65
libavcodec/aarch64/me_cmp_neon.S
View File

@ -584,3 +584,68 @@ function sse4_neon, export=1
ret
endfunc
function vsad16_neon, export=1
// x0 unused
// x1 uint8_t *pix1
// x2 uint8_t *pix2
// x3 ptrdiff_t stride
// w4 int h
ld1 {v0.16b}, [x1], x3 // Load pix1[0], first iteration
ld1 {v1.16b}, [x2], x3 // Load pix2[0], first iteration
sub w4, w4, #1 // we need to make h-1 iterations
movi v16.8h, #0
cmp w4, #3 // check if we can make 3 iterations at once
usubl v31.8h, v0.8b, v1.8b // Signed difference pix1[0] - pix2[0], first iteration
usubl2 v30.8h, v0.16b, v1.16b // Signed difference pix1[0] - pix2[0], first iteration
b.lt 2f
1:
// abs(pix1[0] - pix2[0] - pix1[0 + stride] + pix2[0 + stride])
ld1 {v0.16b}, [x1], x3 // Load pix1[0 + stride], first iteration
ld1 {v1.16b}, [x2], x3 // Load pix2[0 + stride], first iteration
ld1 {v2.16b}, [x1], x3 // Load pix1[0 + stride], second iteration
ld1 {v3.16b}, [x2], x3 // Load pix2[0 + stride], second iteration
usubl v29.8h, v0.8b, v1.8b // Signed difference pix1[0 + stride] - pix2[0 + stride], first iteration
usubl2 v28.8h, v0.16b, v1.16b // Signed difference pix1[0 + stride] - pix2[0 + stride], first iteration
ld1 {v4.16b}, [x1], x3 // Load pix1[0 + stride], third iteration
ld1 {v5.16b}, [x2], x3 // Load pix2[0 + stride], third iteration
usubl v27.8h, v2.8b, v3.8b // Signed difference pix1[0 + stride] - pix2[0 + stride], second iteration
saba v16.8h, v31.8h, v29.8h // Signed absolute difference and accumulate the result. first iteration
usubl2 v26.8h, v2.16b, v3.16b // Signed difference pix1[0 + stride] - pix2[0 + stride], second iteration
saba v16.8h, v30.8h, v28.8h // Signed absolute difference and accumulate the result. first iteration
usubl v25.8h, v4.8b, v5.8b // Signed difference pix1[0 + stride] - pix2[0 + stride], third iteration
usubl2 v24.8h, v4.16b, v5.16b // Signed difference pix1[0 + stride] - pix2[0 + stride], third iteration
saba v16.8h, v29.8h, v27.8h // Signed absolute difference and accumulate the result. second iteration
mov v31.16b, v25.16b
saba v16.8h, v28.8h, v26.8h // Signed absolute difference and accumulate the result. second iteration
sub w4, w4, #3 // h -= 3
mov v30.16b, v24.16b
saba v16.8h, v27.8h, v25.8h // Signed absolute difference and accumulate the result. third iteration
cmp w4, #3
saba v16.8h, v26.8h, v24.8h // Signed absolute difference and accumulate the result. third iteration
b.ge 1b
cbz w4, 3f
2:
ld1 {v0.16b}, [x1], x3
ld1 {v1.16b}, [x2], x3
subs w4, w4, #1
usubl v29.8h, v0.8b, v1.8b
usubl2 v28.8h, v0.16b, v1.16b
saba v16.8h, v31.8h, v29.8h
mov v31.16b, v29.16b
saba v16.8h, v30.8h, v28.8h
mov v30.16b, v28.16b
b.ne 2b
3:
uaddlv s17, v16.8h
fmov w0, s17
ret
endfunc