From dfe224f377be3e45758c69d881ca7874b82d647a Mon Sep 17 00:00:00 2001 From: Janne Grunau Date: Mon, 13 Jan 2014 01:06:20 +0100 Subject: aarch64: get_cabac inline asm Based on the x86 branchless get_cabac asm. get_cabac_noinline() gets approximately 20% faster (no cycle counts available) compared to clang from Xcode 5.1 beta5. More than 6% faster overall. A part of the overall speedup might be explained by additional inlining of get_cabac(). --- libavcodec/aarch64/cabac.h | 104 +++++++++++++++++++++++++++++++++++++++++++ libavcodec/cabac.h | 1 + libavcodec/cabac_functions.h | 4 +- 3 files changed, 108 insertions(+), 1 deletion(-) create mode 100644 libavcodec/aarch64/cabac.h diff --git a/libavcodec/aarch64/cabac.h b/libavcodec/aarch64/cabac.h new file mode 100644 index 0000000000..e12953e86c --- /dev/null +++ b/libavcodec/aarch64/cabac.h @@ -0,0 +1,104 @@ +/* + * 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 + */ + +#ifndef AVCODEC_AARCH64_CABAC_H +#define AVCODEC_AARCH64_CABAC_H + +#include "config.h" +#if HAVE_INLINE_ASM + +#include "libavutil/attributes.h" +#include "libavutil/internal.h" +#include "libavcodec/cabac.h" + +#define get_cabac_inline get_cabac_inline_aarch64 +static av_always_inline int get_cabac_inline_aarch64(CABACContext *c, + uint8_t *const state) +{ + int bit; + void *reg_a, *reg_b, *reg_c, *tmp; + + __asm__ volatile( + "ldrb %w[bit] , [%[state]] \n\t" + "add %[r_b] , %[tables] , %[lps_off] \n\t" + "mov %w[tmp] , %w[range] \n\t" + "and %w[range] , %w[range] , #0xC0 \n\t" + "lsl %w[r_c] , %w[range] , #1 \n\t" + "add %[r_b] , %[r_b] , %w[bit], UXTW \n\t" + "ldrb %w[range] , [%[r_b], %w[r_c], SXTW] \n\t" + "sub %w[r_c] , %w[tmp] , %w[range] \n\t" + "lsl %w[tmp] , %w[r_c] , #17 \n\t" + "cmp %w[tmp] , %w[low] \n\t" + "csel %w[tmp] , %w[tmp] , wzr , cc \n\t" + "csel %w[range] , %w[r_c] , %w[range], gt \n\t" + "cinv %w[bit] , %w[bit] , cc \n\t" + "sub %w[low] , %w[low] , %w[tmp] \n\t" + "add %[r_b] , %[tables] , %[norm_off] \n\t" + "add %[r_a] , %[tables] , %[mlps_off] \n\t" + "ldrb %w[tmp] , [%[r_b], %w[range], SXTW] \n\t" + "ldrb %w[r_a] , [%[r_a], %w[bit], SXTW] \n\t" + "lsl %w[low] , %w[low] , %w[tmp] \n\t" + "lsl %w[range] , %w[range] , %w[tmp] \n\t" + "uxth %w[r_c] , %w[low] \n\t" + "strb %w[r_a] , [%[state]] \n\t" + "cbnz %w[r_c] , 2f \n\t" + "ldr %[r_c] , [%[c], %[byte]] \n\t" + "ldr %[r_a] , [%[c], %[end]] \n\t" + "ldrh %w[tmp] , [%[r_c]] \n\t" + "cmp %[r_c] , %[r_a] \n\t" + "b.ge 1f \n\t" + "add %[r_a] , %[r_c] , #2 \n\t" + "str %[r_a] , [%[c], %[byte]] \n\t" + "1: \n\t" + "sub %w[r_c] , %w[low] , #1 \n\t" + "eor %w[r_c] , %w[r_c] , %w[low] \n\t" + "rev %w[tmp] , %w[tmp] \n\t" + "lsr %w[r_c] , %w[r_c] , #15 \n\t" + "lsr %w[tmp] , %w[tmp] , #15 \n\t" + "ldrb %w[r_c] , [%[r_b], %w[r_c], SXTW] \n\t" + "mov %w[r_b] , #0xFFFF \n\t" + "mov %w[r_a] , #7 \n\t" + "sub %w[tmp] , %w[tmp] , %w[r_b] \n\t" + "sub %w[r_c] , %w[r_a] , %w[r_c] \n\t" + "lsl %w[tmp] , %w[tmp] , %w[r_c] \n\t" + "add %w[low] , %w[low] , %w[tmp] \n\t" + "2: \n\t" + : [bit]"=&r"(bit), + [low]"+&r"(c->low), + [range]"+&r"(c->range), + [r_a]"=&r"(reg_a), + [r_b]"=&r"(reg_b), + [r_c]"=&r"(reg_c), + [tmp]"=&r"(tmp) + : [c]"r"(c), + [state]"r"(state), + [tables]"r"(ff_h264_cabac_tables), + [byte]"i"(offsetof(CABACContext, bytestream)), + [end]"i"(offsetof(CABACContext, bytestream_end)), + [norm_off]"I"(H264_NORM_SHIFT_OFFSET), + [lps_off]"I"(H264_LPS_RANGE_OFFSET), + [mlps_off]"I"(H264_MLPS_STATE_OFFSET + 128) + : "memory", "cc" + ); + + return bit & 1; +} + +#endif /* HAVE_INLINE_ASM */ + +#endif /* AVCODEC_AARCH64_CABAC_H */ diff --git a/libavcodec/cabac.h b/libavcodec/cabac.h index 7401bc96a9..426f338e34 100644 --- a/libavcodec/cabac.h +++ b/libavcodec/cabac.h @@ -31,6 +31,7 @@ #include "put_bits.h" +extern uint8_t ff_h264_cabac_tables[512 + 4*2*64 + 4*64 + 63]; #define H264_NORM_SHIFT_OFFSET 0 #define H264_LPS_RANGE_OFFSET 512 #define H264_MLPS_STATE_OFFSET 1024 diff --git a/libavcodec/cabac_functions.h b/libavcodec/cabac_functions.h index 11c9646742..39f0afbb36 100644 --- a/libavcodec/cabac_functions.h +++ b/libavcodec/cabac_functions.h @@ -32,11 +32,13 @@ #include "cabac.h" #include "config.h" +#if ARCH_AARCH64 +# include "aarch64/cabac.h" +#endif #if ARCH_X86 # include "x86/cabac.h" #endif -extern uint8_t ff_h264_cabac_tables[512 + 4*2*64 + 4*64 + 63]; static uint8_t * const ff_h264_norm_shift = ff_h264_cabac_tables + H264_NORM_SHIFT_OFFSET; static uint8_t * const ff_h264_lps_range = ff_h264_cabac_tables + H264_LPS_RANGE_OFFSET; static uint8_t * const ff_h264_mlps_state = ff_h264_cabac_tables + H264_MLPS_STATE_OFFSET; -- cgit v1.2.3