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ffmpeg/libavcodec/x86/h264_i386.h
Roland Scheidegger 82c71913e4 h264: new assembly version of get_cabac for x86_64 with PIC 
This adds a hand-optimized assembly version for get_cabac much like the
existing one, but it works if the table offsets are RIP-relative.
Compared to the non-RIP-relative version this adds 2 lea instructions
and it needs one extra register.
There is a surprisingly large performance improvement over the c version (more
so than the generated assembly seems to suggest) just in get_cabac, I measured
roughly 40% faster for get_cabac on a K8. However, overall the difference is
not that big, I measured roughly 5% on a test clip on a K8 and a Core2.
Hopefully it still compiles on x86 32bit...
Now that only one table is used, there's some chance even darwin as compiles
this (apparently the label arithmetic used previously doesn't work if it
involves symbols defined in a different file, thanks to Ronald S. Bultje for
helping me with this).

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
2012-04-28 20:02:27 +02:00

189 lines
7.0 KiB
C
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/*
* H.26L/H.264/AVC/JVT/14496-10/... encoder/decoder
* Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
*
* This file is part of FFmpeg.
*
* FFmpeg 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.
*
* FFmpeg 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 FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* H.264 / AVC / MPEG4 part10 codec.
* non-MMX i386-specific optimizations for H.264
* @author Michael Niedermayer <michaelni@gmx.at>
*/
#ifndef AVCODEC_X86_H264_I386_H
#define AVCODEC_X86_H264_I386_H
#include <stddef.h>
#include "libavcodec/cabac.h"
#include "cabac.h"
//FIXME use some macros to avoid duplicating get_cabac (cannot be done yet
//as that would make optimization work hard)
#if HAVE_7REGS
static int decode_significance_x86(CABACContext *c, int max_coeff,
uint8_t *significant_coeff_ctx_base,
int *index, x86_reg last_off){
void *end= significant_coeff_ctx_base + max_coeff - 1;
int minusstart= -(intptr_t)significant_coeff_ctx_base;
int minusindex= 4-(intptr_t)index;
int bit;
x86_reg coeff_count;
#ifdef BROKEN_RELOCATIONS
void *tables;
__asm__ volatile(
"lea "MANGLE(ff_h264_cabac_tables)", %0 \n\t"
: "=&r"(tables)
);
#endif
__asm__ volatile(
"3: \n\t"
BRANCHLESS_GET_CABAC("%4", "%q4", "(%1)", "%3", "%w3",
"%5", "%q5", "%k0", "%b0",
"%a11(%6)", "%a12(%6)", "%a13", "%a14", "%a15", "%16")
"test $1, %4 \n\t"
" jz 4f \n\t"
"add %10, %1 \n\t"
BRANCHLESS_GET_CABAC("%4", "%q4", "(%1)", "%3", "%w3",
"%5", "%q5", "%k0", "%b0",
"%a11(%6)", "%a12(%6)", "%a13", "%a14", "%a15", "%16")
"sub %10, %1 \n\t"
"mov %2, %0 \n\t"
"movl %7, %%ecx \n\t"
"add %1, %%"REG_c" \n\t"
"movl %%ecx, (%0) \n\t"
"test $1, %4 \n\t"
" jnz 5f \n\t"
"add"OPSIZE" $4, %2 \n\t"
"4: \n\t"
"add $1, %1 \n\t"
"cmp %8, %1 \n\t"
" jb 3b \n\t"
"mov %2, %0 \n\t"
"movl %7, %%ecx \n\t"
"add %1, %%"REG_c" \n\t"
"movl %%ecx, (%0) \n\t"
"5: \n\t"
"add %9, %k0 \n\t"
"shr $2, %k0 \n\t"
: "=&q"(coeff_count), "+r"(significant_coeff_ctx_base), "+m"(index),
"+&r"(c->low), "=&r"(bit), "+&r"(c->range)
: "r"(c), "m"(minusstart), "m"(end), "m"(minusindex), "m"(last_off),
"i"(offsetof(CABACContext, bytestream)),
"i"(offsetof(CABACContext, bytestream_end)),
"i"(H264_NORM_SHIFT_OFFSET),
"i"(H264_LPS_RANGE_OFFSET),
"i"(H264_MLPS_STATE_OFFSET) TABLES_ARG
: "%"REG_c, "memory"
);
return coeff_count;
}
static int decode_significance_8x8_x86(CABACContext *c,
uint8_t *significant_coeff_ctx_base,
int *index, uint8_t *last_coeff_ctx_base, const uint8_t *sig_off){
int minusindex= 4-(intptr_t)index;
int bit;
x86_reg coeff_count;
x86_reg last=0;
x86_reg state;
#ifdef BROKEN_RELOCATIONS
void *tables;
__asm__ volatile(
"lea "MANGLE(ff_h264_cabac_tables)", %0 \n\t"
: "=&r"(tables)
);
#endif
__asm__ volatile(
"mov %1, %6 \n\t"
"3: \n\t"
"mov %10, %0 \n\t"
"movzbl (%0, %6), %k6 \n\t"
"add %9, %6 \n\t"
BRANCHLESS_GET_CABAC("%4", "%q4", "(%6)", "%3", "%w3",
"%5", "%q5", "%k0", "%b0",
"%a12(%7)", "%a13(%7)", "%a14", "%a15", "%a16", "%18")
"mov %1, %k6 \n\t"
"test $1, %4 \n\t"
" jz 4f \n\t"
#ifdef BROKEN_RELOCATIONS
"movzbl %a17(%18, %q6), %k6\n\t"
#else
"movzbl "MANGLE(ff_h264_cabac_tables)"+%a17(%k6), %k6\n\t"
#endif
"add %11, %6 \n\t"
BRANCHLESS_GET_CABAC("%4", "%q4", "(%6)", "%3", "%w3",
"%5", "%q5", "%k0", "%b0",
"%a12(%7)", "%a13(%7)", "%a14", "%a15", "%a16", "%18")
"mov %2, %0 \n\t"
"mov %1, %k6 \n\t"
"movl %k6, (%0) \n\t"
"test $1, %4 \n\t"
" jnz 5f \n\t"
"add"OPSIZE" $4, %2 \n\t"
"4: \n\t"
"addl $1, %k6 \n\t"
"mov %k6, %1 \n\t"
"cmpl $63, %k6 \n\t"
" jb 3b \n\t"
"mov %2, %0 \n\t"
"movl %k6, (%0) \n\t"
"5: \n\t"
"addl %8, %k0 \n\t"
"shr $2, %k0 \n\t"
: "=&q"(coeff_count), "+m"(last), "+m"(index), "+&r"(c->low),
"=&r"(bit), "+&r"(c->range), "=&r"(state)
: "r"(c), "m"(minusindex), "m"(significant_coeff_ctx_base),
"m"(sig_off), "m"(last_coeff_ctx_base),
"i"(offsetof(CABACContext, bytestream)),
"i"(offsetof(CABACContext, bytestream_end)),
"i"(H264_NORM_SHIFT_OFFSET),
"i"(H264_LPS_RANGE_OFFSET),
"i"(H264_MLPS_STATE_OFFSET),
"i"(H264_LAST_COEFF_FLAG_OFFSET_8x8_OFFSET) TABLES_ARG
: "%"REG_c, "memory"
);
return coeff_count;
}
#endif /* HAVE_7REGS && !defined(BROKEN_RELOCATIONS) */
#endif /* AVCODEC_X86_H264_I386_H */
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