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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 Libav.
5  *
6  * Libav 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  * Libav 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 Libav; 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/x86/asm.h"
27 #include "libavutil/internal.h"
28 #include "config.h"
29 
30 #if HAVE_INLINE_ASM
31 
32 #ifdef BROKEN_RELOCATIONS
33 #define TABLES_ARG , "r"(tables)
34 
35 #if HAVE_FAST_CMOV
36 #define BRANCHLESS_GET_CABAC_UPDATE(ret, retq, low, range, tmp) \
37  "cmp "low" , "tmp" \n\t"\
38  "cmova %%ecx , "range" \n\t"\
39  "sbb %%rcx , %%rcx \n\t"\
40  "and %%ecx , "tmp" \n\t"\
41  "xor %%rcx , "retq" \n\t"\
42  "sub "tmp" , "low" \n\t"
43 #else /* HAVE_FAST_CMOV */
44 #define BRANCHLESS_GET_CABAC_UPDATE(ret, retq, low, range, tmp) \
45 /* P4 Prescott has crappy cmov,sbb,64bit shift so avoid them */ \
46  "sub "low" , "tmp" \n\t"\
47  "sar $31 , "tmp" \n\t"\
48  "sub %%ecx , "range" \n\t"\
49  "and "tmp" , "range" \n\t"\
50  "add %%ecx , "range" \n\t"\
51  "shl $17 , %%ecx \n\t"\
52  "and "tmp" , %%ecx \n\t"\
53  "sub %%ecx , "low" \n\t"\
54  "xor "tmp" , "ret" \n\t"\
55  "movslq "ret" , "retq" \n\t"
56 #endif /* HAVE_FAST_CMOV */
57 
58 #define BRANCHLESS_GET_CABAC(ret, retq, statep, low, lowword, range, rangeq, tmp, tmpbyte, byte, end, norm_off, lps_off, mlps_off, tables) \
59  "movzbl "statep" , "ret" \n\t"\
60  "mov "range" , "tmp" \n\t"\
61  "and $0xC0 , "range" \n\t"\
62  "lea ("ret", "range", 2), %%ecx \n\t"\
63  "movzbl "lps_off"("tables", %%rcx), "range" \n\t"\
64  "sub "range" , "tmp" \n\t"\
65  "mov "tmp" , %%ecx \n\t"\
66  "shl $17 , "tmp" \n\t"\
67  BRANCHLESS_GET_CABAC_UPDATE(ret, retq, low, range, tmp) \
68  "movzbl "norm_off"("tables", "rangeq"), %%ecx \n\t"\
69  "shl %%cl , "range" \n\t"\
70  "movzbl "mlps_off"+128("tables", "retq"), "tmp" \n\t"\
71  "shl %%cl , "low" \n\t"\
72  "mov "tmpbyte" , "statep" \n\t"\
73  "test "lowword" , "lowword" \n\t"\
74  "jnz 2f \n\t"\
75  "mov "byte" , %%"REG_c" \n\t"\
76  "add"OPSIZE" $2 , "byte" \n\t"\
77  "movzwl (%%"REG_c") , "tmp" \n\t"\
78  "lea -1("low") , %%ecx \n\t"\
79  "xor "low" , %%ecx \n\t"\
80  "shr $15 , %%ecx \n\t"\
81  "bswap "tmp" \n\t"\
82  "shr $15 , "tmp" \n\t"\
83  "movzbl "norm_off"("tables", %%rcx), %%ecx \n\t"\
84  "sub $0xFFFF , "tmp" \n\t"\
85  "neg %%ecx \n\t"\
86  "add $7 , %%ecx \n\t"\
87  "shl %%cl , "tmp" \n\t"\
88  "add "tmp" , "low" \n\t"\
89  "2: \n\t"
90 
91 #else /* BROKEN_RELOCATIONS */
92 #define TABLES_ARG
93 #define RIP_ARG
94 
95 #if HAVE_FAST_CMOV
96 #define BRANCHLESS_GET_CABAC_UPDATE(ret, low, range, tmp)\
97  "mov "tmp" , %%ecx \n\t"\
98  "shl $17 , "tmp" \n\t"\
99  "cmp "low" , "tmp" \n\t"\
100  "cmova %%ecx , "range" \n\t"\
101  "sbb %%ecx , %%ecx \n\t"\
102  "and %%ecx , "tmp" \n\t"\
103  "xor %%ecx , "ret" \n\t"\
104  "sub "tmp" , "low" \n\t"
105 #else /* HAVE_FAST_CMOV */
106 #define BRANCHLESS_GET_CABAC_UPDATE(ret, low, range, tmp)\
107  "mov "tmp" , %%ecx \n\t"\
108  "shl $17 , "tmp" \n\t"\
109  "sub "low" , "tmp" \n\t"\
110  "sar $31 , "tmp" \n\t" /*lps_mask*/\
111  "sub %%ecx , "range" \n\t" /*RangeLPS - range*/\
112  "and "tmp" , "range" \n\t" /*(RangeLPS - range)&lps_mask*/\
113  "add %%ecx , "range" \n\t" /*new range*/\
114  "shl $17 , %%ecx \n\t"\
115  "and "tmp" , %%ecx \n\t"\
116  "sub %%ecx , "low" \n\t"\
117  "xor "tmp" , "ret" \n\t"
118 #endif /* HAVE_FAST_CMOV */
119 
120 #define BRANCHLESS_GET_CABAC(ret, retq, statep, low, lowword, range, rangeq, tmp, tmpbyte, byte, end, norm_off, lps_off, mlps_off, tables) \
121  "movzbl "statep" , "ret" \n\t"\
122  "mov "range" , "tmp" \n\t"\
123  "and $0xC0 , "range" \n\t"\
124  "movzbl "MANGLE(ff_h264_cabac_tables)"+"lps_off"("ret", "range", 2), "range" \n\t"\
125  "sub "range" , "tmp" \n\t"\
126  BRANCHLESS_GET_CABAC_UPDATE(ret, low, range, tmp) \
127  "movzbl "MANGLE(ff_h264_cabac_tables)"+"norm_off"("range"), %%ecx \n\t"\
128  "shl %%cl , "range" \n\t"\
129  "movzbl "MANGLE(ff_h264_cabac_tables)"+"mlps_off"+128("ret"), "tmp" \n\t"\
130  "shl %%cl , "low" \n\t"\
131  "mov "tmpbyte" , "statep" \n\t"\
132  "test "lowword" , "lowword" \n\t"\
133  " jnz 2f \n\t"\
134  "mov "byte" , %%"REG_c" \n\t"\
135  "add"OPSIZE" $2 , "byte" \n\t"\
136  "movzwl (%%"REG_c") , "tmp" \n\t"\
137  "lea -1("low") , %%ecx \n\t"\
138  "xor "low" , %%ecx \n\t"\
139  "shr $15 , %%ecx \n\t"\
140  "bswap "tmp" \n\t"\
141  "shr $15 , "tmp" \n\t"\
142  "movzbl "MANGLE(ff_h264_cabac_tables)"+"norm_off"(%%ecx), %%ecx \n\t"\
143  "sub $0xFFFF , "tmp" \n\t"\
144  "neg %%ecx \n\t"\
145  "add $7 , %%ecx \n\t"\
146  "shl %%cl , "tmp" \n\t"\
147  "add "tmp" , "low" \n\t"\
148  "2: \n\t"
149 
150 #endif /* BROKEN_RELOCATIONS */
151 
152 
153 #if HAVE_7REGS && !(defined(__i386) && defined(__clang__) && (__clang_major__<2 || (__clang_major__==2 && __clang_minor__<10)))\
154  && !(defined(__i386) && !defined(__clang__) && defined(__llvm__) && __GNUC__==4 && __GNUC_MINOR__==2 && __GNUC_PATCHLEVEL__<=1)
155 #define get_cabac_inline get_cabac_inline_x86
156 static av_always_inline int get_cabac_inline_x86(CABACContext *c,
157  uint8_t *const state)
158 {
159  int bit, tmp;
160 #ifdef BROKEN_RELOCATIONS
161  void *tables;
162 
163  __asm__ volatile(
164  "lea "MANGLE(ff_h264_cabac_tables)", %0 \n\t"
165  : "=&r"(tables)
166  );
167 #endif
168 
169  __asm__ volatile(
170  BRANCHLESS_GET_CABAC("%0", "%q0", "(%4)", "%1", "%w1",
171  "%2", "%q2", "%3", "%b3",
172  "%c6(%5)", "%c7(%5)",
173  AV_STRINGIFY(H264_NORM_SHIFT_OFFSET),
174  AV_STRINGIFY(H264_LPS_RANGE_OFFSET),
175  AV_STRINGIFY(H264_MLPS_STATE_OFFSET),
176  "%8")
177  : "=&r"(bit), "=&r"(c->low), "=&r"(c->range), "=&q"(tmp)
178  : "r"(state), "r"(c),
179  "i"(offsetof(CABACContext, bytestream)),
180  "i"(offsetof(CABACContext, bytestream_end))
181  TABLES_ARG
182  ,"1"(c->low), "2"(c->range)
183  : "%"REG_c, "memory"
184  );
185  return bit & 1;
186 }
187 #endif /* HAVE_7REGS */
188 
189 #define get_cabac_bypass_sign get_cabac_bypass_sign_x86
190 static av_always_inline int get_cabac_bypass_sign_x86(CABACContext *c, int val)
191 {
192  x86_reg tmp;
193  __asm__ volatile(
194  "movl %c6(%2), %k1 \n\t"
195  "movl %c3(%2), %%eax \n\t"
196  "shl $17, %k1 \n\t"
197  "add %%eax, %%eax \n\t"
198  "sub %k1, %%eax \n\t"
199  "cltd \n\t"
200  "and %%edx, %k1 \n\t"
201  "add %k1, %%eax \n\t"
202  "xor %%edx, %%ecx \n\t"
203  "sub %%edx, %%ecx \n\t"
204  "test %%ax, %%ax \n\t"
205  "jnz 1f \n\t"
206  "mov %c4(%2), %1 \n\t"
207  "subl $0xFFFF, %%eax \n\t"
208  "movzwl (%1), %%edx \n\t"
209  "bswap %%edx \n\t"
210  "shrl $15, %%edx \n\t"
211  "add $2, %1 \n\t"
212  "addl %%edx, %%eax \n\t"
213  "mov %1, %c4(%2) \n\t"
214  "1: \n\t"
215  "movl %%eax, %c3(%2) \n\t"
216 
217  : "+c"(val), "=&r"(tmp)
218  : "r"(c),
219  "i"(offsetof(CABACContext, low)),
220  "i"(offsetof(CABACContext, bytestream)),
221  "i"(offsetof(CABACContext, bytestream_end)),
222  "i"(offsetof(CABACContext, range))
223  : "%eax", "%edx", "memory"
224  );
225  return val;
226 }
227 
228 #endif /* HAVE_INLINE_ASM */
229 #endif /* AVCODEC_X86_CABAC_H */
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