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_cpu.h"
27 #include "config.h"
28 
29 #if HAVE_FAST_CMOV
30 #define BRANCHLESS_GET_CABAC_UPDATE(ret, statep, low, lowword, range, tmp)\
31  "mov "tmp" , %%ecx \n\t"\
32  "shl $17 , "tmp" \n\t"\
33  "cmp "low" , "tmp" \n\t"\
34  "cmova %%ecx , "range" \n\t"\
35  "sbb %%ecx , %%ecx \n\t"\
36  "and %%ecx , "tmp" \n\t"\
37  "xor %%ecx , "ret" \n\t"\
38  "sub "tmp" , "low" \n\t"
39 #else /* HAVE_FAST_CMOV */
40 #define BRANCHLESS_GET_CABAC_UPDATE(ret, statep, low, lowword, range, tmp)\
41  "mov "tmp" , %%ecx \n\t"\
42  "shl $17 , "tmp" \n\t"\
43  "sub "low" , "tmp" \n\t"\
44  "sar $31 , "tmp" \n\t" /*lps_mask*/\
45  "sub %%ecx , "range" \n\t" /*RangeLPS - range*/\
46  "and "tmp" , "range" \n\t" /*(RangeLPS - range)&lps_mask*/\
47  "add %%ecx , "range" \n\t" /*new range*/\
48  "shl $17 , %%ecx \n\t"\
49  "and "tmp" , %%ecx \n\t"\
50  "sub %%ecx , "low" \n\t"\
51  "xor "tmp" , "ret" \n\t"
52 #endif /* HAVE_FAST_CMOV */
53 
54 #define BRANCHLESS_GET_CABAC(ret, statep, low, lowword, range, tmp, tmpbyte, byte) \
55  "movzbl "statep" , "ret" \n\t"\
56  "mov "range" , "tmp" \n\t"\
57  "and $0xC0 , "range" \n\t"\
58  "movzbl "MANGLE(ff_h264_lps_range)"("ret", "range", 2), "range" \n\t"\
59  "sub "range" , "tmp" \n\t"\
60  BRANCHLESS_GET_CABAC_UPDATE(ret, statep, low, lowword, range, tmp) \
61  "movzbl " MANGLE(ff_h264_norm_shift) "("range"), %%ecx \n\t"\
62  "shl %%cl , "range" \n\t"\
63  "movzbl "MANGLE(ff_h264_mlps_state)"+128("ret"), "tmp" \n\t"\
64  "shl %%cl , "low" \n\t"\
65  "mov "tmpbyte" , "statep" \n\t"\
66  "test "lowword" , "lowword" \n\t"\
67  " jnz 1f \n\t"\
68  "mov "byte" , %%"REG_c" \n\t"\
69  "add"OPSIZE" $2 , "byte" \n\t"\
70  "movzwl (%%"REG_c") , "tmp" \n\t"\
71  "lea -1("low") , %%ecx \n\t"\
72  "xor "low" , %%ecx \n\t"\
73  "shr $15 , %%ecx \n\t"\
74  "bswap "tmp" \n\t"\
75  "shr $15 , "tmp" \n\t"\
76  "movzbl " MANGLE(ff_h264_norm_shift) "(%%ecx), %%ecx \n\t"\
77  "sub $0xFFFF , "tmp" \n\t"\
78  "neg %%ecx \n\t"\
79  "add $7 , %%ecx \n\t"\
80  "shl %%cl , "tmp" \n\t"\
81  "add "tmp" , "low" \n\t"\
82  "1: \n\t"
83 
84 #if HAVE_7REGS && !defined(BROKEN_RELOCATIONS)
85 #define get_cabac_inline get_cabac_inline_x86
86 static av_always_inline int get_cabac_inline_x86(CABACContext *c,
87  uint8_t *const state)
88 {
89  int bit, tmp;
90 
91  __asm__ volatile(
92  BRANCHLESS_GET_CABAC("%0", "(%5)", "%1", "%w1", "%2",
93  "%3", "%b3", "%4")
94  :"=&r"(bit), "+&r"(c->low), "+&r"(c->range), "=&q"(tmp),
95  "+m"(c->bytestream)
96  :"r"(state)
97  : "%"REG_c, "memory"
98  );
99  return bit & 1;
100 }
101 #endif /* HAVE_7REGS && !defined(BROKEN_RELOCATIONS) */
102 
103 #define get_cabac_bypass_sign get_cabac_bypass_sign_x86
105 {
106  x86_reg tmp;
107  __asm__ volatile(
108  "movl %4, %k1 \n\t"
109  "movl %2, %%eax \n\t"
110  "shl $17, %k1 \n\t"
111  "add %%eax, %%eax \n\t"
112  "sub %k1, %%eax \n\t"
113  "cltd \n\t"
114  "and %%edx, %k1 \n\t"
115  "add %k1, %%eax \n\t"
116  "xor %%edx, %%ecx \n\t"
117  "sub %%edx, %%ecx \n\t"
118  "test %%ax, %%ax \n\t"
119  " jnz 1f \n\t"
120  "mov %3, %1 \n\t"
121  "subl $0xFFFF, %%eax \n\t"
122  "movzwl (%1), %%edx \n\t"
123  "bswap %%edx \n\t"
124  "shrl $15, %%edx \n\t"
125  "add $2, %1 \n\t"
126  "addl %%edx, %%eax \n\t"
127  "mov %1, %3 \n\t"
128  "1: \n\t"
129  "movl %%eax, %2 \n\t"
130 
131  :"+c"(val), "=&r"(tmp), "+m"(c->low), "+m"(c->bytestream)
132  :"m"(c->range)
133  : "%eax", "%edx"
134  );
135  return val;
136 }
137 
138 #endif /* AVCODEC_X86_CABAC_H */