[FFmpeg-cvslog] avcodec/vc1: Arm 64-bit NEON unescape fast path
Ben Avison
git at videolan.org
Fri Apr 1 10:04:39 EEST 2022
ffmpeg | branch: master | Ben Avison <bavison at riscosopen.org> | Thu Mar 31 18:23:50 2022 +0100| [6eee65028957c3b16287a204e648caebcc86b06c] | committer: Martin Storsjö
avcodec/vc1: Arm 64-bit NEON unescape fast path
checkasm benchmarks on 1.5 GHz Cortex-A72 are as follows.
vc1dsp.vc1_unescape_buffer_c: 655617.7
vc1dsp.vc1_unescape_buffer_neon: 118237.0
Signed-off-by: Ben Avison <bavison at riscosopen.org>
Signed-off-by: Martin Storsjö <martin at martin.st>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=6eee65028957c3b16287a204e648caebcc86b06c
---
libavcodec/aarch64/vc1dsp_init_aarch64.c | 61 +++++++++++
libavcodec/aarch64/vc1dsp_neon.S | 176 +++++++++++++++++++++++++++++++
2 files changed, 237 insertions(+)
diff --git a/libavcodec/aarch64/vc1dsp_init_aarch64.c b/libavcodec/aarch64/vc1dsp_init_aarch64.c
index e0eb52dd63..a7976fd596 100644
--- a/libavcodec/aarch64/vc1dsp_init_aarch64.c
+++ b/libavcodec/aarch64/vc1dsp_init_aarch64.c
@@ -21,6 +21,7 @@
#include "libavutil/attributes.h"
#include "libavutil/cpu.h"
#include "libavutil/aarch64/cpu.h"
+#include "libavutil/intreadwrite.h"
#include "libavcodec/vc1dsp.h"
#include "config.h"
@@ -51,6 +52,64 @@ void ff_put_vc1_chroma_mc4_neon(uint8_t *dst, uint8_t *src, ptrdiff_t stride,
void ff_avg_vc1_chroma_mc4_neon(uint8_t *dst, uint8_t *src, ptrdiff_t stride,
int h, int x, int y);
+int ff_vc1_unescape_buffer_helper_neon(const uint8_t *src, int size, uint8_t *dst);
+
+static int vc1_unescape_buffer_neon(const uint8_t *src, int size, uint8_t *dst)
+{
+ /* Dealing with starting and stopping, and removing escape bytes, are
+ * comparatively less time-sensitive, so are more clearly expressed using
+ * a C wrapper around the assembly inner loop. Note that we assume a
+ * little-endian machine that supports unaligned loads. */
+ int dsize = 0;
+ while (size >= 4)
+ {
+ int found = 0;
+ while (!found && (((uintptr_t) dst) & 7) && size >= 4)
+ {
+ found = (AV_RL32(src) &~ 0x03000000) == 0x00030000;
+ if (!found)
+ {
+ *dst++ = *src++;
+ --size;
+ ++dsize;
+ }
+ }
+ if (!found)
+ {
+ int skip = size - ff_vc1_unescape_buffer_helper_neon(src, size, dst);
+ dst += skip;
+ src += skip;
+ size -= skip;
+ dsize += skip;
+ while (!found && size >= 4)
+ {
+ found = (AV_RL32(src) &~ 0x03000000) == 0x00030000;
+ if (!found)
+ {
+ *dst++ = *src++;
+ --size;
+ ++dsize;
+ }
+ }
+ }
+ if (found)
+ {
+ *dst++ = *src++;
+ *dst++ = *src++;
+ ++src;
+ size -= 3;
+ dsize += 2;
+ }
+ }
+ while (size > 0)
+ {
+ *dst++ = *src++;
+ --size;
+ ++dsize;
+ }
+ return dsize;
+}
+
av_cold void ff_vc1dsp_init_aarch64(VC1DSPContext *dsp)
{
int cpu_flags = av_get_cpu_flags();
@@ -76,5 +135,7 @@ av_cold void ff_vc1dsp_init_aarch64(VC1DSPContext *dsp)
dsp->avg_no_rnd_vc1_chroma_pixels_tab[0] = ff_avg_vc1_chroma_mc8_neon;
dsp->put_no_rnd_vc1_chroma_pixels_tab[1] = ff_put_vc1_chroma_mc4_neon;
dsp->avg_no_rnd_vc1_chroma_pixels_tab[1] = ff_avg_vc1_chroma_mc4_neon;
+
+ dsp->vc1_unescape_buffer = vc1_unescape_buffer_neon;
}
}
diff --git a/libavcodec/aarch64/vc1dsp_neon.S b/libavcodec/aarch64/vc1dsp_neon.S
index 0201db4f78..9a96c2523c 100644
--- a/libavcodec/aarch64/vc1dsp_neon.S
+++ b/libavcodec/aarch64/vc1dsp_neon.S
@@ -1368,3 +1368,179 @@ function ff_vc1_h_loop_filter16_neon, export=1
st2 {v2.b, v3.b}[7], [x6]
4: ret
endfunc
+
+// Copy at most the specified number of bytes from source to destination buffer,
+// stopping at a multiple of 32 bytes, none of which are the start of an escape sequence
+// On entry:
+// x0 -> source buffer
+// w1 = max number of bytes to copy
+// x2 -> destination buffer, optimally 8-byte aligned
+// On exit:
+// w0 = number of bytes not copied
+function ff_vc1_unescape_buffer_helper_neon, export=1
+ // Offset by 80 to screen out cases that are too short for us to handle,
+ // and also make it easy to test for loop termination, or to determine
+ // whether we need an odd number of half-iterations of the loop.
+ subs w1, w1, #80
+ b.mi 90f
+
+ // Set up useful constants
+ movi v20.4s, #3, lsl #24
+ movi v21.4s, #3, lsl #16
+
+ tst w1, #32
+ b.ne 1f
+
+ ld1 {v0.16b, v1.16b, v2.16b}, [x0], #48
+ ext v25.16b, v0.16b, v1.16b, #1
+ ext v26.16b, v0.16b, v1.16b, #2
+ ext v27.16b, v0.16b, v1.16b, #3
+ ext v29.16b, v1.16b, v2.16b, #1
+ ext v30.16b, v1.16b, v2.16b, #2
+ ext v31.16b, v1.16b, v2.16b, #3
+ bic v24.16b, v0.16b, v20.16b
+ bic v25.16b, v25.16b, v20.16b
+ bic v26.16b, v26.16b, v20.16b
+ bic v27.16b, v27.16b, v20.16b
+ bic v28.16b, v1.16b, v20.16b
+ bic v29.16b, v29.16b, v20.16b
+ bic v30.16b, v30.16b, v20.16b
+ bic v31.16b, v31.16b, v20.16b
+ eor v24.16b, v24.16b, v21.16b
+ eor v25.16b, v25.16b, v21.16b
+ eor v26.16b, v26.16b, v21.16b
+ eor v27.16b, v27.16b, v21.16b
+ eor v28.16b, v28.16b, v21.16b
+ eor v29.16b, v29.16b, v21.16b
+ eor v30.16b, v30.16b, v21.16b
+ eor v31.16b, v31.16b, v21.16b
+ cmeq v24.4s, v24.4s, #0
+ cmeq v25.4s, v25.4s, #0
+ cmeq v26.4s, v26.4s, #0
+ cmeq v27.4s, v27.4s, #0
+ add w1, w1, #32
+ b 3f
+
+1: ld1 {v3.16b, v4.16b, v5.16b}, [x0], #48
+ ext v25.16b, v3.16b, v4.16b, #1
+ ext v26.16b, v3.16b, v4.16b, #2
+ ext v27.16b, v3.16b, v4.16b, #3
+ ext v29.16b, v4.16b, v5.16b, #1
+ ext v30.16b, v4.16b, v5.16b, #2
+ ext v31.16b, v4.16b, v5.16b, #3
+ bic v24.16b, v3.16b, v20.16b
+ bic v25.16b, v25.16b, v20.16b
+ bic v26.16b, v26.16b, v20.16b
+ bic v27.16b, v27.16b, v20.16b
+ bic v28.16b, v4.16b, v20.16b
+ bic v29.16b, v29.16b, v20.16b
+ bic v30.16b, v30.16b, v20.16b
+ bic v31.16b, v31.16b, v20.16b
+ eor v24.16b, v24.16b, v21.16b
+ eor v25.16b, v25.16b, v21.16b
+ eor v26.16b, v26.16b, v21.16b
+ eor v27.16b, v27.16b, v21.16b
+ eor v28.16b, v28.16b, v21.16b
+ eor v29.16b, v29.16b, v21.16b
+ eor v30.16b, v30.16b, v21.16b
+ eor v31.16b, v31.16b, v21.16b
+ cmeq v24.4s, v24.4s, #0
+ cmeq v25.4s, v25.4s, #0
+ cmeq v26.4s, v26.4s, #0
+ cmeq v27.4s, v27.4s, #0
+ // Drop through...
+2: mov v0.16b, v5.16b
+ ld1 {v1.16b, v2.16b}, [x0], #32
+ cmeq v28.4s, v28.4s, #0
+ cmeq v29.4s, v29.4s, #0
+ cmeq v30.4s, v30.4s, #0
+ cmeq v31.4s, v31.4s, #0
+ orr v24.16b, v24.16b, v25.16b
+ orr v26.16b, v26.16b, v27.16b
+ orr v28.16b, v28.16b, v29.16b
+ orr v30.16b, v30.16b, v31.16b
+ ext v25.16b, v0.16b, v1.16b, #1
+ orr v22.16b, v24.16b, v26.16b
+ ext v26.16b, v0.16b, v1.16b, #2
+ ext v27.16b, v0.16b, v1.16b, #3
+ ext v29.16b, v1.16b, v2.16b, #1
+ orr v23.16b, v28.16b, v30.16b
+ ext v30.16b, v1.16b, v2.16b, #2
+ ext v31.16b, v1.16b, v2.16b, #3
+ bic v24.16b, v0.16b, v20.16b
+ bic v25.16b, v25.16b, v20.16b
+ bic v26.16b, v26.16b, v20.16b
+ orr v22.16b, v22.16b, v23.16b
+ bic v27.16b, v27.16b, v20.16b
+ bic v28.16b, v1.16b, v20.16b
+ bic v29.16b, v29.16b, v20.16b
+ bic v30.16b, v30.16b, v20.16b
+ bic v31.16b, v31.16b, v20.16b
+ addv s22, v22.4s
+ eor v24.16b, v24.16b, v21.16b
+ eor v25.16b, v25.16b, v21.16b
+ eor v26.16b, v26.16b, v21.16b
+ eor v27.16b, v27.16b, v21.16b
+ eor v28.16b, v28.16b, v21.16b
+ mov w3, v22.s[0]
+ eor v29.16b, v29.16b, v21.16b
+ eor v30.16b, v30.16b, v21.16b
+ eor v31.16b, v31.16b, v21.16b
+ cmeq v24.4s, v24.4s, #0
+ cmeq v25.4s, v25.4s, #0
+ cmeq v26.4s, v26.4s, #0
+ cmeq v27.4s, v27.4s, #0
+ cbnz w3, 90f
+ st1 {v3.16b, v4.16b}, [x2], #32
+3: mov v3.16b, v2.16b
+ ld1 {v4.16b, v5.16b}, [x0], #32
+ cmeq v28.4s, v28.4s, #0
+ cmeq v29.4s, v29.4s, #0
+ cmeq v30.4s, v30.4s, #0
+ cmeq v31.4s, v31.4s, #0
+ orr v24.16b, v24.16b, v25.16b
+ orr v26.16b, v26.16b, v27.16b
+ orr v28.16b, v28.16b, v29.16b
+ orr v30.16b, v30.16b, v31.16b
+ ext v25.16b, v3.16b, v4.16b, #1
+ orr v22.16b, v24.16b, v26.16b
+ ext v26.16b, v3.16b, v4.16b, #2
+ ext v27.16b, v3.16b, v4.16b, #3
+ ext v29.16b, v4.16b, v5.16b, #1
+ orr v23.16b, v28.16b, v30.16b
+ ext v30.16b, v4.16b, v5.16b, #2
+ ext v31.16b, v4.16b, v5.16b, #3
+ bic v24.16b, v3.16b, v20.16b
+ bic v25.16b, v25.16b, v20.16b
+ bic v26.16b, v26.16b, v20.16b
+ orr v22.16b, v22.16b, v23.16b
+ bic v27.16b, v27.16b, v20.16b
+ bic v28.16b, v4.16b, v20.16b
+ bic v29.16b, v29.16b, v20.16b
+ bic v30.16b, v30.16b, v20.16b
+ bic v31.16b, v31.16b, v20.16b
+ addv s22, v22.4s
+ eor v24.16b, v24.16b, v21.16b
+ eor v25.16b, v25.16b, v21.16b
+ eor v26.16b, v26.16b, v21.16b
+ eor v27.16b, v27.16b, v21.16b
+ eor v28.16b, v28.16b, v21.16b
+ mov w3, v22.s[0]
+ eor v29.16b, v29.16b, v21.16b
+ eor v30.16b, v30.16b, v21.16b
+ eor v31.16b, v31.16b, v21.16b
+ cmeq v24.4s, v24.4s, #0
+ cmeq v25.4s, v25.4s, #0
+ cmeq v26.4s, v26.4s, #0
+ cmeq v27.4s, v27.4s, #0
+ cbnz w3, 91f
+ st1 {v0.16b, v1.16b}, [x2], #32
+ subs w1, w1, #64
+ b.pl 2b
+
+90: add w0, w1, #80
+ ret
+
+91: sub w1, w1, #32
+ b 90b
+endfunc
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