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cabac.h
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1 /*
2  * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 #ifndef AVCODEC_X86_CABAC_H
22 #define AVCODEC_X86_CABAC_H
23 
24 #include "libavcodec/cabac.h"
25 #include "libavutil/attributes.h"
26 #include "libavutil/macros.h"
27 #include "libavutil/x86/asm.h"
28 #include "config.h"
29 
30 #if (defined(__i386) && defined(__clang__) && (__clang_major__<2 || (__clang_major__==2 && __clang_minor__<10)))\
31  || ( !defined(__clang__) && defined(__llvm__) && __GNUC__==4 && __GNUC_MINOR__==2 && __GNUC_PATCHLEVEL__<=1)\
32  || (defined(__INTEL_COMPILER) && defined(_MSC_VER))
33 # define BROKEN_COMPILER 1
34 #else
35 # define BROKEN_COMPILER 0
36 #endif
37 
38 #if HAVE_INLINE_ASM
39 
40 #ifndef UNCHECKED_BITSTREAM_READER
41 #define UNCHECKED_BITSTREAM_READER !CONFIG_SAFE_BITSTREAM_READER
42 #endif
43 
44 #if UNCHECKED_BITSTREAM_READER
45 #define END_CHECK(end) ""
46 #else
47 #define END_CHECK(end) \
48  "cmp "end" , %%"REG_c" \n\t"\
49  "jge 1f \n\t"
50 #endif
51 
52 #ifdef BROKEN_RELOCATIONS
53 #define TABLES_ARG , "r"(tables)
54 
55 #if HAVE_FAST_CMOV
56 #define BRANCHLESS_GET_CABAC_UPDATE(ret, retq, low, range, tmp) \
57  "cmp "low" , "tmp" \n\t"\
58  "cmova %%ecx , "range" \n\t"\
59  "sbb %%rcx , %%rcx \n\t"\
60  "and %%ecx , "tmp" \n\t"\
61  "xor %%rcx , "retq" \n\t"\
62  "sub "tmp" , "low" \n\t"
63 #else /* HAVE_FAST_CMOV */
64 #define BRANCHLESS_GET_CABAC_UPDATE(ret, retq, low, range, tmp) \
65 /* P4 Prescott has crappy cmov,sbb,64bit shift so avoid them */ \
66  "sub "low" , "tmp" \n\t"\
67  "sar $31 , "tmp" \n\t"\
68  "sub %%ecx , "range" \n\t"\
69  "and "tmp" , "range" \n\t"\
70  "add %%ecx , "range" \n\t"\
71  "shl $17 , %%ecx \n\t"\
72  "and "tmp" , %%ecx \n\t"\
73  "sub %%ecx , "low" \n\t"\
74  "xor "tmp" , "ret" \n\t"\
75  "movslq "ret" , "retq" \n\t"
76 #endif /* HAVE_FAST_CMOV */
77 
78 #define BRANCHLESS_GET_CABAC(ret, retq, statep, low, lowword, range, rangeq, tmp, tmpbyte, byte, end, norm_off, lps_off, mlps_off, tables) \
79  "movzbl "statep" , "ret" \n\t"\
80  "mov "range" , "tmp" \n\t"\
81  "and $0xC0 , "range" \n\t"\
82  "lea ("ret", "range", 2), %%ecx \n\t"\
83  "movzbl "lps_off"("tables", %%rcx), "range" \n\t"\
84  "sub "range" , "tmp" \n\t"\
85  "mov "tmp" , %%ecx \n\t"\
86  "shl $17 , "tmp" \n\t"\
87  BRANCHLESS_GET_CABAC_UPDATE(ret, retq, low, range, tmp) \
88  "movzbl "norm_off"("tables", "rangeq"), %%ecx \n\t"\
89  "shl %%cl , "range" \n\t"\
90  "movzbl "mlps_off"+128("tables", "retq"), "tmp" \n\t"\
91  "shl %%cl , "low" \n\t"\
92  "mov "tmpbyte" , "statep" \n\t"\
93  "test "lowword" , "lowword" \n\t"\
94  "jnz 2f \n\t"\
95  "mov "byte" , %%"REG_c" \n\t"\
96  END_CHECK(end)\
97  "add"OPSIZE" $2 , "byte" \n\t"\
98  "1: \n\t"\
99  "movzwl (%%"REG_c") , "tmp" \n\t"\
100  "lea -1("low") , %%ecx \n\t"\
101  "xor "low" , %%ecx \n\t"\
102  "shr $15 , %%ecx \n\t"\
103  "bswap "tmp" \n\t"\
104  "shr $15 , "tmp" \n\t"\
105  "movzbl "norm_off"("tables", %%rcx), %%ecx \n\t"\
106  "sub $0xFFFF , "tmp" \n\t"\
107  "neg %%ecx \n\t"\
108  "add $7 , %%ecx \n\t"\
109  "shl %%cl , "tmp" \n\t"\
110  "add "tmp" , "low" \n\t"\
111  "2: \n\t"
112 
113 #else /* BROKEN_RELOCATIONS */
114 #define TABLES_ARG NAMED_CONSTRAINTS_ARRAY_ADD(ff_h264_cabac_tables)
115 #define RIP_ARG
116 
117 #if HAVE_FAST_CMOV
118 #define BRANCHLESS_GET_CABAC_UPDATE(ret, low, range, tmp)\
119  "mov "tmp" , %%ecx \n\t"\
120  "shl $17 , "tmp" \n\t"\
121  "cmp "low" , "tmp" \n\t"\
122  "cmova %%ecx , "range" \n\t"\
123  "sbb %%ecx , %%ecx \n\t"\
124  "and %%ecx , "tmp" \n\t"\
125  "xor %%ecx , "ret" \n\t"\
126  "sub "tmp" , "low" \n\t"
127 #else /* HAVE_FAST_CMOV */
128 #define BRANCHLESS_GET_CABAC_UPDATE(ret, low, range, tmp)\
129  "mov "tmp" , %%ecx \n\t"\
130  "shl $17 , "tmp" \n\t"\
131  "sub "low" , "tmp" \n\t"\
132  "sar $31 , "tmp" \n\t" /*lps_mask*/\
133  "sub %%ecx , "range" \n\t" /*RangeLPS - range*/\
134  "and "tmp" , "range" \n\t" /*(RangeLPS - range)&lps_mask*/\
135  "add %%ecx , "range" \n\t" /*new range*/\
136  "shl $17 , %%ecx \n\t"\
137  "and "tmp" , %%ecx \n\t"\
138  "sub %%ecx , "low" \n\t"\
139  "xor "tmp" , "ret" \n\t"
140 #endif /* HAVE_FAST_CMOV */
141 
142 #define BRANCHLESS_GET_CABAC(ret, retq, statep, low, lowword, range, rangeq, tmp, tmpbyte, byte, end, norm_off, lps_off, mlps_off, tables) \
143  "movzbl "statep" , "ret" \n\t"\
144  "mov "range" , "tmp" \n\t"\
145  "and $0xC0 , "range" \n\t"\
146  "movzbl "MANGLE(ff_h264_cabac_tables)"+"lps_off"("ret", "range", 2), "range" \n\t"\
147  "sub "range" , "tmp" \n\t"\
148  BRANCHLESS_GET_CABAC_UPDATE(ret, low, range, tmp) \
149  "movzbl "MANGLE(ff_h264_cabac_tables)"+"norm_off"("range"), %%ecx \n\t"\
150  "shl %%cl , "range" \n\t"\
151  "movzbl "MANGLE(ff_h264_cabac_tables)"+"mlps_off"+128("ret"), "tmp" \n\t"\
152  "shl %%cl , "low" \n\t"\
153  "mov "tmpbyte" , "statep" \n\t"\
154  "test "lowword" , "lowword" \n\t"\
155  " jnz 2f \n\t"\
156  "mov "byte" , %%"REG_c" \n\t"\
157  END_CHECK(end)\
158  "add"OPSIZE" $2 , "byte" \n\t"\
159  "1: \n\t"\
160  "movzwl (%%"REG_c") , "tmp" \n\t"\
161  "lea -1("low") , %%ecx \n\t"\
162  "xor "low" , %%ecx \n\t"\
163  "shr $15 , %%ecx \n\t"\
164  "bswap "tmp" \n\t"\
165  "shr $15 , "tmp" \n\t"\
166  "movzbl "MANGLE(ff_h264_cabac_tables)"+"norm_off"(%%ecx), %%ecx \n\t"\
167  "sub $0xFFFF , "tmp" \n\t"\
168  "neg %%ecx \n\t"\
169  "add $7 , %%ecx \n\t"\
170  "shl %%cl , "tmp" \n\t"\
171  "add "tmp" , "low" \n\t"\
172  "2: \n\t"
173 
174 #endif /* BROKEN_RELOCATIONS */
175 
176 #if HAVE_7REGS && !BROKEN_COMPILER
177 #define get_cabac_inline get_cabac_inline_x86
178 static av_always_inline int get_cabac_inline_x86(CABACContext *c,
179  uint8_t *const state)
180 {
181  int bit, tmp;
182 #ifdef BROKEN_RELOCATIONS
183  void *tables;
184 
185  __asm__ volatile(
186  "lea "MANGLE(ff_h264_cabac_tables)", %0 \n\t"
187  : "=&r"(tables)
188  : NAMED_CONSTRAINTS_ARRAY(ff_h264_cabac_tables)
189  );
190 #endif
191 
192  __asm__ volatile(
193  BRANCHLESS_GET_CABAC("%0", "%q0", "(%4)", "%1", "%w1",
194  "%2", "%q2", "%3", "%b3",
195  "%c6(%5)", "%c7(%5)",
196  AV_STRINGIFY(H264_NORM_SHIFT_OFFSET),
197  AV_STRINGIFY(H264_LPS_RANGE_OFFSET),
198  AV_STRINGIFY(H264_MLPS_STATE_OFFSET),
199  "%8")
200  : "=&r"(bit), "=&r"(c->low), "=&r"(c->range), "=&q"(tmp)
201  : "r"(state), "r"(c),
202  "i"(offsetof(CABACContext, bytestream)),
203  "i"(offsetof(CABACContext, bytestream_end))
204  TABLES_ARG
205  ,"1"(c->low), "2"(c->range)
206  : "%"REG_c, "memory"
207  );
208  return bit & 1;
209 }
210 #endif /* HAVE_7REGS && !BROKEN_COMPILER */
211 
212 #if !BROKEN_COMPILER
213 #define get_cabac_bypass_sign get_cabac_bypass_sign_x86
214 static av_always_inline int get_cabac_bypass_sign_x86(CABACContext *c, int val)
215 {
216  x86_reg tmp;
217  __asm__ volatile(
218  "movl %c6(%2), %k1 \n\t"
219  "movl %c3(%2), %%eax \n\t"
220  "shl $17, %k1 \n\t"
221  "add %%eax, %%eax \n\t"
222  "sub %k1, %%eax \n\t"
223  "cdq \n\t"
224  "and %%edx, %k1 \n\t"
225  "add %k1, %%eax \n\t"
226  "xor %%edx, %%ecx \n\t"
227  "sub %%edx, %%ecx \n\t"
228  "test %%ax, %%ax \n\t"
229  "jnz 1f \n\t"
230  "mov %c4(%2), %1 \n\t"
231  "subl $0xFFFF, %%eax \n\t"
232  "movzwl (%1), %%edx \n\t"
233  "bswap %%edx \n\t"
234  "shrl $15, %%edx \n\t"
235 #if UNCHECKED_BITSTREAM_READER
236  "add $2, %1 \n\t"
237  "addl %%edx, %%eax \n\t"
238  "mov %1, %c4(%2) \n\t"
239 #else
240  "addl %%edx, %%eax \n\t"
241  "cmp %c5(%2), %1 \n\t"
242  "jge 1f \n\t"
243  "add"OPSIZE" $2, %c4(%2) \n\t"
244 #endif
245  "1: \n\t"
246  "movl %%eax, %c3(%2) \n\t"
247 
248  : "+c"(val), "=&r"(tmp)
249  : "r"(c),
250  "i"(offsetof(CABACContext, low)),
251  "i"(offsetof(CABACContext, bytestream)),
252  "i"(offsetof(CABACContext, bytestream_end)),
253  "i"(offsetof(CABACContext, range))
254  : "%eax", "%edx", "memory"
255  );
256  return val;
257 }
258 
259 #define get_cabac_bypass get_cabac_bypass_x86
260 static av_always_inline int get_cabac_bypass_x86(CABACContext *c)
261 {
262  x86_reg tmp;
263  int res;
264  __asm__ volatile(
265  "movl %c6(%2), %k1 \n\t"
266  "movl %c3(%2), %%eax \n\t"
267  "shl $17, %k1 \n\t"
268  "add %%eax, %%eax \n\t"
269  "sub %k1, %%eax \n\t"
270  "cdq \n\t"
271  "and %%edx, %k1 \n\t"
272  "add %k1, %%eax \n\t"
273  "inc %%edx \n\t"
274  "test %%ax, %%ax \n\t"
275  "jnz 1f \n\t"
276  "mov %c4(%2), %1 \n\t"
277  "subl $0xFFFF, %%eax \n\t"
278  "movzwl (%1), %%ecx \n\t"
279  "bswap %%ecx \n\t"
280  "shrl $15, %%ecx \n\t"
281  "addl %%ecx, %%eax \n\t"
282  "cmp %c5(%2), %1 \n\t"
283  "jge 1f \n\t"
284  "add"OPSIZE" $2, %c4(%2) \n\t"
285  "1: \n\t"
286  "movl %%eax, %c3(%2) \n\t"
287 
288  : "=&d"(res), "=&r"(tmp)
289  : "r"(c),
290  "i"(offsetof(CABACContext, low)),
291  "i"(offsetof(CABACContext, bytestream)),
292  "i"(offsetof(CABACContext, bytestream_end)),
293  "i"(offsetof(CABACContext, range))
294  : "%eax", "%ecx", "memory"
295  );
296  return res;
297 }
298 #endif /* !BROKEN_COMPILER */
299 
300 #endif /* HAVE_INLINE_ASM */
301 #endif /* AVCODEC_X86_CABAC_H */
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