[FFmpeg-cvslog] arm: Add assembly version of h264_find_start_code_candidate
Ben Avison
git at videolan.org
Thu Aug 8 12:57:19 CEST 2013
ffmpeg | branch: master | Ben Avison <bavison at riscosopen.org> | Mon Aug 5 13:12:48 2013 +0100| [45e10e5c8d3df09c80a4d80483bff2712367f3fa] | committer: Martin Storsjö
arm: Add assembly version of h264_find_start_code_candidate
Before After
Mean StdDev Mean StdDev Change
This function 508.8 23.4 185.4 9.0 +174.4%
Overall 3068.5 31.7 2752.1 29.4 +11.5%
In combination with the preceding patch:
Before After
Mean StdDev Mean StdDev Change
Overall 2925.6 26.2 2752.1 29.4 +6.3%
Signed-off-by: Martin Storsjö <martin at martin.st>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=45e10e5c8d3df09c80a4d80483bff2712367f3fa
---
libavcodec/arm/Makefile | 1 +
libavcodec/arm/h264dsp_armv6.S | 253 +++++++++++++++++++++++++++++++++++++
libavcodec/arm/h264dsp_init_arm.c | 4 +
3 files changed, 258 insertions(+)
diff --git a/libavcodec/arm/Makefile b/libavcodec/arm/Makefile
index e941aaa..9c64b36 100644
--- a/libavcodec/arm/Makefile
+++ b/libavcodec/arm/Makefile
@@ -45,6 +45,7 @@ ARMV6-OBJS-$(CONFIG_DSPUTIL) += arm/dsputil_init_armv6.o \
arm/simple_idct_armv6.o \
ARMV6-OBJS-$(CONFIG_AC3DSP) += arm/ac3dsp_armv6.o
+ARMV6-OBJS-$(CONFIG_H264DSP) += arm/h264dsp_armv6.o
ARMV6-OBJS-$(CONFIG_HPELDSP) += arm/hpeldsp_init_armv6.o \
arm/hpeldsp_armv6.o
ARMV6-OBJS-$(CONFIG_MPEGAUDIODSP) += arm/mpegaudiodsp_fixed_armv6.o
diff --git a/libavcodec/arm/h264dsp_armv6.S b/libavcodec/arm/h264dsp_armv6.S
new file mode 100644
index 0000000..c4f12a6
--- /dev/null
+++ b/libavcodec/arm/h264dsp_armv6.S
@@ -0,0 +1,253 @@
+/*
+ * Copyright (c) 2013 RISC OS Open Ltd
+ * Author: Ben Avison <bavison at riscosopen.org>
+ *
+ * This file is part of Libav.
+ *
+ * Libav is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * Libav is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "libavutil/arm/asm.S"
+
+RESULT .req a1
+BUF .req a1
+SIZE .req a2
+PATTERN .req a3
+PTR .req a4
+DAT0 .req v1
+DAT1 .req v2
+DAT2 .req v3
+DAT3 .req v4
+TMP0 .req v5
+TMP1 .req v6
+TMP2 .req ip
+TMP3 .req lr
+
+#define PRELOAD_DISTANCE 4
+
+.macro innerloop4
+ ldr DAT0, [PTR], #4
+ subs SIZE, SIZE, #4 @ C flag survives rest of macro
+ sub TMP0, DAT0, PATTERN, lsr #14
+ bic TMP0, TMP0, DAT0
+ ands TMP0, TMP0, PATTERN
+.endm
+
+.macro innerloop16 decrement, do_preload
+ ldmia PTR!, {DAT0,DAT1,DAT2,DAT3}
+ .ifnc "\do_preload",""
+ pld [PTR, #PRELOAD_DISTANCE*32]
+ .endif
+ .ifnc "\decrement",""
+ subs SIZE, SIZE, #\decrement @ C flag survives rest of macro
+ .endif
+ sub TMP0, DAT0, PATTERN, lsr #14
+ sub TMP1, DAT1, PATTERN, lsr #14
+ bic TMP0, TMP0, DAT0
+ bic TMP1, TMP1, DAT1
+ sub TMP2, DAT2, PATTERN, lsr #14
+ sub TMP3, DAT3, PATTERN, lsr #14
+ ands TMP0, TMP0, PATTERN
+ bic TMP2, TMP2, DAT2
+ it eq
+ andseq TMP1, TMP1, PATTERN
+ bic TMP3, TMP3, DAT3
+ itt eq
+ andseq TMP2, TMP2, PATTERN
+ andseq TMP3, TMP3, PATTERN
+.endm
+
+/* int ff_h264_find_start_code_candidate_armv6(const uint8_t *buf, int size) */
+function ff_h264_find_start_code_candidate_armv6, export=1
+ push {v1-v6,lr}
+ mov PTR, BUF
+ @ Ensure there are at least (PRELOAD_DISTANCE+2) complete cachelines to go
+ @ before using code that does preloads
+ cmp SIZE, #(PRELOAD_DISTANCE+3)*32 - 1
+ blo 60f
+
+ @ Get to word-alignment, 1 byte at a time
+ tst PTR, #3
+ beq 2f
+1: ldrb DAT0, [PTR], #1
+ sub SIZE, SIZE, #1
+ teq DAT0, #0
+ beq 90f
+ tst PTR, #3
+ bne 1b
+2: @ Get to 4-word alignment, 1 word at a time
+ ldr PATTERN, =0x80008000
+ setend be
+ tst PTR, #12
+ beq 4f
+3: innerloop4
+ bne 91f
+ tst PTR, #12
+ bne 3b
+4: @ Get to cacheline (8-word) alignment
+ tst PTR, #16
+ beq 5f
+ innerloop16 16
+ bne 93f
+5: @ Check complete cachelines, with preloading
+ @ We need to stop when there are still (PRELOAD_DISTANCE+1)
+ @ complete cachelines to go
+ sub SIZE, SIZE, #(PRELOAD_DISTANCE+2)*32
+6: innerloop16 , do_preload
+ bne 93f
+ innerloop16 32
+ bne 93f
+ bcs 6b
+ @ Preload trailing part-cacheline, if any
+ tst SIZE, #31
+ beq 7f
+ pld [PTR, #(PRELOAD_DISTANCE+1)*32]
+ @ Check remaining data without doing any more preloads. First
+ @ do in chunks of 4 words:
+7: adds SIZE, SIZE, #(PRELOAD_DISTANCE+2)*32 - 16
+ bmi 9f
+8: innerloop16 16
+ bne 93f
+ bcs 8b
+ @ Then in words:
+9: adds SIZE, SIZE, #16 - 4
+ bmi 11f
+10: innerloop4
+ bne 91f
+ bcs 10b
+11: setend le
+ @ Check second byte of final halfword
+ ldrb DAT0, [PTR, #-1]
+ teq DAT0, #0
+ beq 90f
+ @ Check any remaining bytes
+ tst SIZE, #3
+ beq 13f
+12: ldrb DAT0, [PTR], #1
+ sub SIZE, SIZE, #1
+ teq DAT0, #0
+ beq 90f
+ tst SIZE, #3
+ bne 12b
+ @ No candidate found
+13: sub RESULT, PTR, BUF
+ b 99f
+
+60: @ Small buffer - simply check by looping over bytes
+ subs SIZE, SIZE, #1
+ bcc 99f
+61: ldrb DAT0, [PTR], #1
+ subs SIZE, SIZE, #1
+ teq DAT0, #0
+ beq 90f
+ bcs 61b
+ @ No candidate found
+ sub RESULT, PTR, BUF
+ b 99f
+
+90: @ Found a candidate at the preceding byte
+ sub RESULT, PTR, BUF
+ sub RESULT, RESULT, #1
+ b 99f
+
+91: @ Found a candidate somewhere in the preceding 4 bytes
+ sub RESULT, PTR, BUF
+ sub RESULT, RESULT, #4
+ sub TMP0, DAT0, #0x20000
+ bics TMP0, TMP0, DAT0
+ itt pl
+ ldrbpl DAT0, [PTR, #-3]
+ addpl RESULT, RESULT, #2
+ bpl 92f
+ teq RESULT, #0
+ beq 98f @ don't look back a byte if found at first byte in buffer
+ ldrb DAT0, [PTR, #-5]
+92: teq DAT0, #0
+ it eq
+ subeq RESULT, RESULT, #1
+ b 98f
+
+93: @ Found a candidate somewhere in the preceding 16 bytes
+ sub RESULT, PTR, BUF
+ sub RESULT, RESULT, #16
+ teq TMP0, #0
+ beq 95f @ not in first 4 bytes
+ sub TMP0, DAT0, #0x20000
+ bics TMP0, TMP0, DAT0
+ itt pl
+ ldrbpl DAT0, [PTR, #-15]
+ addpl RESULT, RESULT, #2
+ bpl 94f
+ teq RESULT, #0
+ beq 98f @ don't look back a byte if found at first byte in buffer
+ ldrb DAT0, [PTR, #-17]
+94: teq DAT0, #0
+ it eq
+ subeq RESULT, RESULT, #1
+ b 98f
+95: add RESULT, RESULT, #4
+ teq TMP1, #0
+ beq 96f @ not in next 4 bytes
+ sub TMP1, DAT1, #0x20000
+ bics TMP1, TMP1, DAT1
+ itee mi
+ ldrbmi DAT0, [PTR, #-13]
+ ldrbpl DAT0, [PTR, #-11]
+ addpl RESULT, RESULT, #2
+ teq DAT0, #0
+ it eq
+ subeq RESULT, RESULT, #1
+ b 98f
+96: add RESULT, RESULT, #4
+ teq TMP2, #0
+ beq 97f @ not in next 4 bytes
+ sub TMP2, DAT2, #0x20000
+ bics TMP2, TMP2, DAT2
+ itee mi
+ ldrbmi DAT0, [PTR, #-9]
+ ldrbpl DAT0, [PTR, #-7]
+ addpl RESULT, RESULT, #2
+ teq DAT0, #0
+ it eq
+ subeq RESULT, RESULT, #1
+ b 98f
+97: add RESULT, RESULT, #4
+ sub TMP3, DAT3, #0x20000
+ bics TMP3, TMP3, DAT3
+ itee mi
+ ldrbmi DAT0, [PTR, #-5]
+ ldrbpl DAT0, [PTR, #-3]
+ addpl RESULT, RESULT, #2
+ teq DAT0, #0
+ it eq
+ subeq RESULT, RESULT, #1
+ @ drop through to 98f
+98: setend le
+99: pop {v1-v6,pc}
+.endfunc
+
+ .unreq RESULT
+ .unreq BUF
+ .unreq SIZE
+ .unreq PATTERN
+ .unreq PTR
+ .unreq DAT0
+ .unreq DAT1
+ .unreq DAT2
+ .unreq DAT3
+ .unreq TMP0
+ .unreq TMP1
+ .unreq TMP2
+ .unreq TMP3
diff --git a/libavcodec/arm/h264dsp_init_arm.c b/libavcodec/arm/h264dsp_init_arm.c
index bb8b3b9..b206a1b 100644
--- a/libavcodec/arm/h264dsp_init_arm.c
+++ b/libavcodec/arm/h264dsp_init_arm.c
@@ -24,6 +24,8 @@
#include "libavutil/arm/cpu.h"
#include "libavcodec/h264dsp.h"
+int ff_h264_find_start_code_candidate_armv6(const uint8_t *buf, int size);
+
void ff_h264_v_loop_filter_luma_neon(uint8_t *pix, int stride, int alpha,
int beta, int8_t *tc0);
void ff_h264_h_loop_filter_luma_neon(uint8_t *pix, int stride, int alpha,
@@ -102,6 +104,8 @@ av_cold void ff_h264dsp_init_arm(H264DSPContext *c, const int bit_depth,
{
int cpu_flags = av_get_cpu_flags();
+ if (have_armv6(cpu_flags))
+ c->h264_find_start_code_candidate = ff_h264_find_start_code_candidate_armv6;
if (have_neon(cpu_flags))
h264dsp_init_neon(c, bit_depth, chroma_format_idc);
}
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