[FFmpeg-devel] [PATCH 1/5] lavc/aarch64: Add neon implementation for vsad16
Hubert Mazur
hum at semihalf.com
Mon Aug 22 18:26:23 EEST 2022
Provide optimized implementation of vsad16 function for arm64.
Performance comparison tests are shown below.
- vsad_0_c: 285.0
- vsad_0_neon: 42.5
Benchmarks and tests are run with checkasm tool on AWS Graviton 3.
Signed-off-by: Hubert Mazur <hum at semihalf.com>
---
libavcodec/aarch64/me_cmp_init_aarch64.c | 5 ++
libavcodec/aarch64/me_cmp_neon.S | 75 ++++++++++++++++++++++++
2 files changed, 80 insertions(+)
diff --git a/libavcodec/aarch64/me_cmp_init_aarch64.c b/libavcodec/aarch64/me_cmp_init_aarch64.c
index fb7c3f5059..ddc5d05611 100644
--- a/libavcodec/aarch64/me_cmp_init_aarch64.c
+++ b/libavcodec/aarch64/me_cmp_init_aarch64.c
@@ -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;
}
}
diff --git a/libavcodec/aarch64/me_cmp_neon.S b/libavcodec/aarch64/me_cmp_neon.S
index 4198985c6c..d4c0099854 100644
--- a/libavcodec/aarch64/me_cmp_neon.S
+++ b/libavcodec/aarch64/me_cmp_neon.S
@@ -584,3 +584,78 @@ 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
+
+ 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
+ add x5, x1, x3 // pix1 + stride
+ add x6, x2, x3 // pix2 + stride
+ b.le 2f
+
+1:
+ // abs(pix1[0] - pix2[0] - pix1[0 + stride] + pix2[0 + stride])
+ // abs(x) = (x < 0 ? (-x) : (x))
+ ld1 {v0.16b}, [x1], x3 // Load pix1[0], first iteration
+ ld1 {v1.16b}, [x2], x3 // Load pix2[0], first iteration
+ ld1 {v2.16b}, [x5], x3 // Load pix1[0 + stride], first iteration
+ usubl v31.8h, v0.8b, v1.8b // Signed difference pix1[0] - pix2[0], first iteration
+ ld1 {v3.16b}, [x6], x3 // Load pix2[0 + stride], first iteration
+ usubl2 v30.8h, v0.16b, v1.16b // Signed difference pix1[0] - pix2[0], first iteration
+ usubl v29.8h, v2.8b, v3.8b // Signed difference pix1[0 + stride] - pix2[0 + stride], first iteration
+ ld1 {v4.16b}, [x1], x3 // Load pix1[0], second iteration
+ usubl2 v28.8h, v2.16b, v3.16b // Signed difference pix1[0 + stride] - pix2[0 + stride], first iteration
+ ld1 {v5.16b}, [x2], x3 // Load pix2[0], second iteration
+ saba v16.8h, v31.8h, v29.8h // Signed absolute difference and accumulate the result. first iteration
+ ld1 {v6.16b}, [x5], x3 // Load pix1[0 + stride], second iteration
+ saba v16.8h, v30.8h, v28.8h // Signed absolute difference and accumulate the result. first iteration
+ usubl v27.8h, v4.8b, v5.8b // Signed difference pix1[0] - pix2[0], second iteration
+ ld1 {v7.16b}, [x6], x3 // Load pix2[0 + stride], second iteration
+ usubl2 v26.8h, v4.16b, v5.16b // Signed difference pix1[0] - pix2[0], second iteration
+ usubl v25.8h, v6.8b, v7.8b // Signed difference pix1[0 + stride] - pix2[0 + stride], second iteration
+ ld1 {v17.16b}, [x1], x3 // Load pix1[0], third iteration
+ usubl2 v24.8h, v6.16b, v7.16b // Signed difference pix1[0 + stride] - pix2[0 + stride], second iteration
+ ld1 {v18.16b}, [x2], x3 // Load pix2[0], second iteration
+ saba v16.8h, v27.8h, v25.8h // Signed absolute difference and accumulate the result. second iteration
+ ld1 {v19.16b}, [x5], x3 // Load pix1[0 + stride], third iteration
+ saba v16.8h, v26.8h, v24.8h // Signed absolute difference and accumulate the result. second iteration
+ usubl v23.8h, v17.8b, v18.8b // Signed difference pix1[0] - pix2[0], third iteration
+ ld1 {v20.16b}, [x6], x3 // Load pix2[0 + stride], third iteration
+ usubl2 v22.8h, v17.16b, v18.16b // Signed difference pix1[0] - pix2[0], third iteration
+ usubl v21.8h, v19.8b, v20.8b // Signed difference pix1[0 + stride] - pix2[0 + stride], third iteration
+ sub w4, w4, #3 // h -= 3
+ saba v16.8h, v23.8h, v21.8h // Signed absolute difference and accumulate the result. third iteration
+ usubl2 v31.8h, v19.16b, v20.16b // Signed difference pix1[0 + stride] - pix2[0 + stride], third iteration
+ cmp w4, #3
+ saba v16.8h, v22.8h, v31.8h // 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
+ ld1 {v2.16b}, [x5], x3
+ usubl v30.8h, v0.8b, v1.8b
+ ld1 {v3.16b}, [x6], x3
+ usubl2 v29.8h, v0.16b, v1.16b
+ usubl v28.8h, v2.8b, v3.8b
+ usubl2 v27.8h, v2.16b, v3.16b
+ saba v16.8h, v30.8h, v28.8h
+ subs w4, w4, #1
+ saba v16.8h, v29.8h, v27.8h
+
+ b.ne 2b
+3:
+ uaddlv s17, v16.8h
+ fmov w0, s17
+
+ ret
+endfunc
--
2.34.1
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