FFmpeg  4.0
h264_cabac.c
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1 /*
2  * H.26L/H.264/AVC/JVT/14496-10/... encoder/decoder
3  * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 /**
23  * @file
24  * H.264 / AVC / MPEG-4 part10 codec.
25  * non-SIMD x86-specific optimizations for H.264
26  * @author Michael Niedermayer <michaelni@gmx.at>
27  */
28 
29 #include <stddef.h>
30 
31 #include "libavcodec/cabac.h"
32 #include "cabac.h"
33 
34 #if HAVE_INLINE_ASM
35 
36 #if ARCH_X86_64
37 #define REG64 "r"
38 #else
39 #define REG64 "m"
40 #endif
41 
42 //FIXME use some macros to avoid duplicating get_cabac (cannot be done yet
43 //as that would make optimization work hard)
44 #if HAVE_7REGS && !BROKEN_COMPILER
45 #define decode_significance decode_significance_x86
46 static int decode_significance_x86(CABACContext *c, int max_coeff,
47  uint8_t *significant_coeff_ctx_base,
48  int *index, x86_reg last_off){
49  void *end= significant_coeff_ctx_base + max_coeff - 1;
50  int minusstart= -(intptr_t)significant_coeff_ctx_base;
51  int minusindex= 4-(intptr_t)index;
52  int bit;
53  x86_reg coeff_count;
54 
55 #ifdef BROKEN_RELOCATIONS
56  void *tables;
57 
58  __asm__ volatile(
59  "lea "MANGLE(ff_h264_cabac_tables)", %0 \n\t"
60  : "=&r"(tables)
61  : NAMED_CONSTRAINTS_ARRAY(ff_h264_cabac_tables)
62  );
63 #endif
64 
65  __asm__ volatile(
66  "3: \n\t"
67 
68  BRANCHLESS_GET_CABAC("%4", "%q4", "(%1)", "%3", "%w3",
69  "%5", "%q5", "%k0", "%b0",
70  "%c11(%6)", "%c12(%6)",
71  AV_STRINGIFY(H264_NORM_SHIFT_OFFSET),
72  AV_STRINGIFY(H264_LPS_RANGE_OFFSET),
73  AV_STRINGIFY(H264_MLPS_STATE_OFFSET),
74  "%13")
75 
76  "test $1, %4 \n\t"
77  " jz 4f \n\t"
78  "add %10, %1 \n\t"
79 
80  BRANCHLESS_GET_CABAC("%4", "%q4", "(%1)", "%3", "%w3",
81  "%5", "%q5", "%k0", "%b0",
82  "%c11(%6)", "%c12(%6)",
83  AV_STRINGIFY(H264_NORM_SHIFT_OFFSET),
84  AV_STRINGIFY(H264_LPS_RANGE_OFFSET),
85  AV_STRINGIFY(H264_MLPS_STATE_OFFSET),
86  "%13")
87 
88  "sub %10, %1 \n\t"
89  "mov %2, %0 \n\t"
90  "movl %7, %%ecx \n\t"
91  "add %1, %%"FF_REG_c" \n\t"
92  "movl %%ecx, (%0) \n\t"
93 
94  "test $1, %4 \n\t"
95  " jnz 5f \n\t"
96 
97  "add"FF_OPSIZE" $4, %2 \n\t"
98 
99  "4: \n\t"
100  "add $1, %1 \n\t"
101  "cmp %8, %1 \n\t"
102  " jb 3b \n\t"
103  "mov %2, %0 \n\t"
104  "movl %7, %%ecx \n\t"
105  "add %1, %%"FF_REG_c" \n\t"
106  "movl %%ecx, (%0) \n\t"
107  "5: \n\t"
108  "add %9, %k0 \n\t"
109  "shr $2, %k0 \n\t"
110  : "=&q"(coeff_count), "+r"(significant_coeff_ctx_base), "+m"(index),
111  "+&r"(c->low), "=&r"(bit), "+&r"(c->range)
112  : "r"(c), "m"(minusstart), "m"(end), "m"(minusindex), "m"(last_off),
113  "i"(offsetof(CABACContext, bytestream)),
114  "i"(offsetof(CABACContext, bytestream_end))
115  TABLES_ARG
116  : "%"FF_REG_c, "memory"
117  );
118  return coeff_count;
119 }
120 
121 #define decode_significance_8x8 decode_significance_8x8_x86
122 static int decode_significance_8x8_x86(CABACContext *c,
123  uint8_t *significant_coeff_ctx_base,
124  int *index, uint8_t *last_coeff_ctx_base, const uint8_t *sig_off){
125  int minusindex= 4-(intptr_t)index;
126  int bit;
127  x86_reg coeff_count;
128  x86_reg last=0;
129  x86_reg state;
130 
131 #ifdef BROKEN_RELOCATIONS
132  void *tables;
133 
134  __asm__ volatile(
135  "lea "MANGLE(ff_h264_cabac_tables)", %0 \n\t"
136  : "=&r"(tables)
137  : NAMED_CONSTRAINTS_ARRAY(ff_h264_cabac_tables)
138  );
139 #endif
140 
141  __asm__ volatile(
142  "mov %1, %6 \n\t"
143  "3: \n\t"
144 
145  "mov %10, %0 \n\t"
146  "movzb (%0, %6), %6 \n\t"
147  "add %9, %6 \n\t"
148 
149  BRANCHLESS_GET_CABAC("%4", "%q4", "(%6)", "%3", "%w3",
150  "%5", "%q5", "%k0", "%b0",
151  "%c12(%7)", "%c13(%7)",
152  AV_STRINGIFY(H264_NORM_SHIFT_OFFSET),
153  AV_STRINGIFY(H264_LPS_RANGE_OFFSET),
154  AV_STRINGIFY(H264_MLPS_STATE_OFFSET),
155  "%15")
156 
157  "mov %1, %6 \n\t"
158  "test $1, %4 \n\t"
159  " jz 4f \n\t"
160 
161 #ifdef BROKEN_RELOCATIONS
162  "movzb %c14(%15, %q6), %6\n\t"
163 #else
164  "movzb "MANGLE(ff_h264_cabac_tables)"+%c14(%6), %6\n\t"
165 #endif
166  "add %11, %6 \n\t"
167 
168  BRANCHLESS_GET_CABAC("%4", "%q4", "(%6)", "%3", "%w3",
169  "%5", "%q5", "%k0", "%b0",
170  "%c12(%7)", "%c13(%7)",
171  AV_STRINGIFY(H264_NORM_SHIFT_OFFSET),
172  AV_STRINGIFY(H264_LPS_RANGE_OFFSET),
173  AV_STRINGIFY(H264_MLPS_STATE_OFFSET),
174  "%15")
175 
176  "mov %2, %0 \n\t"
177  "mov %1, %6 \n\t"
178  "mov %k6, (%0) \n\t"
179 
180  "test $1, %4 \n\t"
181  " jnz 5f \n\t"
182 
183  "add"FF_OPSIZE" $4, %2 \n\t"
184 
185  "4: \n\t"
186  "add $1, %6 \n\t"
187  "mov %6, %1 \n\t"
188  "cmp $63, %6 \n\t"
189  " jb 3b \n\t"
190  "mov %2, %0 \n\t"
191  "mov %k6, (%0) \n\t"
192  "5: \n\t"
193  "addl %8, %k0 \n\t"
194  "shr $2, %k0 \n\t"
195  : "=&q"(coeff_count), "+"REG64(last), "+"REG64(index), "+&r"(c->low),
196  "=&r"(bit), "+&r"(c->range), "=&r"(state)
197  : "r"(c), "m"(minusindex), "m"(significant_coeff_ctx_base),
198  REG64(sig_off), REG64(last_coeff_ctx_base),
199  "i"(offsetof(CABACContext, bytestream)),
200  "i"(offsetof(CABACContext, bytestream_end)),
201  "i"(H264_LAST_COEFF_FLAG_OFFSET_8x8_OFFSET) TABLES_ARG
202  : "%"FF_REG_c, "memory"
203  );
204  return coeff_count;
205 }
206 #endif /* HAVE_7REGS && BROKEN_COMPILER */
207 
208 #endif /* HAVE_INLINE_ASM */
MANGLE
#define MANGLE(a)
Definition: asm.h:127
NAMED_CONSTRAINTS_ARRAY
#define NAMED_CONSTRAINTS_ARRAY(...)
Definition: asm.h:151
uint8_t
uint8_t
Definition: audio_convert.c:194
end
static av_cold int end(AVCodecContext *avctx)
Definition: avrndec.c:90
H264_LAST_COEFF_FLAG_OFFSET_8x8_OFFSET
#define H264_LAST_COEFF_FLAG_OFFSET_8x8_OFFSET
Definition: cabac.h:38
state
static struct @271 state
CABACContext::range
int range
Definition: cabac.h:45
AV_STRINGIFY
#define AV_STRINGIFY(s)
Definition: macros.h:36
H264_MLPS_STATE_OFFSET
#define H264_MLPS_STATE_OFFSET
Definition: cabac.h:37
index
int index
Definition: gxfenc.c:89
H264_NORM_SHIFT_OFFSET
#define H264_NORM_SHIFT_OFFSET
Definition: cabac.h:35
CABACContext::low
int low
Definition: cabac.h:44
ff_h264_cabac_tables
const uint8_t ff_h264_cabac_tables[512+4 *2 *64+4 *64+63]
c
static double c[64]
Definition: vsrc_mptestsrc.c:87
x86_reg
int x86_reg
Definition: asm.h:72
tables
static ConstTables tables[2][NB_SUBBANDS]
Definition: aptx.c:396
cabac.h
Context Adaptive Binary Arithmetic Coder.
H264_LPS_RANGE_OFFSET
#define H264_LPS_RANGE_OFFSET
Definition: cabac.h:36
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