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vp56_arith.h
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1 /*
2  * Copyright (C) 2010 Mans Rullgard <mans@mansr.com>
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_ARM_VP56_ARITH_H
22 #define AVCODEC_ARM_VP56_ARITH_H
23 
24 #if CONFIG_THUMB
25 # define A(x)
26 # define T(x) x
27 #else
28 # define A(x) x
29 # define T(x)
30 #endif
31 
32 #if CONFIG_THUMB || defined __clang__
33 # define L(x)
34 # define U(x) x
35 #else
36 # define L(x) x
37 # define U(x)
38 #endif
39 
40 #if HAVE_ARMV6_INLINE
41 
42 #define vp56_rac_get_prob vp56_rac_get_prob_armv6
43 static inline int vp56_rac_get_prob_armv6(VP56RangeCoder *c, int pr)
44 {
45  unsigned shift = ff_vp56_norm_shift[c->high];
46  unsigned code_word = c->code_word << shift;
47  unsigned high = c->high << shift;
48  unsigned bit;
49 
50  __asm__ ("adds %3, %3, %0 \n"
51  "itt cs \n"
52  "cmpcs %7, %4 \n"
53  L("ldrcsh %2, [%4], #2 \n")
54  U("ldrhcs %2, [%4], #2 \n")
55  "rsb %0, %6, #256 \n"
56  "smlabb %0, %5, %6, %0 \n"
57  T("itttt cs \n")
58  "rev16cs %2, %2 \n"
59  T("lslcs %2, %2, %3 \n")
60  T("orrcs %1, %1, %2 \n")
61  A("orrcs %1, %1, %2, lsl %3 \n")
62  "subcs %3, %3, #16 \n"
63  "lsr %0, %0, #8 \n"
64  "cmp %1, %0, lsl #16 \n"
65  "ittte ge \n"
66  "subge %1, %1, %0, lsl #16 \n"
67  "subge %0, %5, %0 \n"
68  "movge %2, #1 \n"
69  "movlt %2, #0 \n"
70  : "=&r"(c->high), "=&r"(c->code_word), "=&r"(bit),
71  "+&r"(c->bits), "+&r"(c->buffer)
72  : "r"(high), "r"(pr), "r"(c->end - 1),
73  "0"(shift), "1"(code_word)
74  : "cc");
75 
76  return bit;
77 }
78 
79 #define vp56_rac_get_prob_branchy vp56_rac_get_prob_branchy_armv6
80 static inline int vp56_rac_get_prob_branchy_armv6(VP56RangeCoder *c, int pr)
81 {
82  unsigned shift = ff_vp56_norm_shift[c->high];
83  unsigned code_word = c->code_word << shift;
84  unsigned high = c->high << shift;
85  unsigned low;
86  unsigned tmp;
87 
88  __asm__ ("adds %3, %3, %0 \n"
89  "itt cs \n"
90  "cmpcs %7, %4 \n"
91  L("ldrcsh %2, [%4], #2 \n")
92  U("ldrhcs %2, [%4], #2 \n")
93  "rsb %0, %6, #256 \n"
94  "smlabb %0, %5, %6, %0 \n"
95  T("itttt cs \n")
96  "rev16cs %2, %2 \n"
97  T("lslcs %2, %2, %3 \n")
98  T("orrcs %1, %1, %2 \n")
99  A("orrcs %1, %1, %2, lsl %3 \n")
100  "subcs %3, %3, #16 \n"
101  "lsr %0, %0, #8 \n"
102  "lsl %2, %0, #16 \n"
103  : "=&r"(low), "+&r"(code_word), "=&r"(tmp),
104  "+&r"(c->bits), "+&r"(c->buffer)
105  : "r"(high), "r"(pr), "r"(c->end - 1), "0"(shift)
106  : "cc");
107 
108  if (code_word >= tmp) {
109  c->high = high - low;
110  c->code_word = code_word - tmp;
111  return 1;
112  }
113 
114  c->high = low;
115  c->code_word = code_word;
116  return 0;
117 }
118 
119 #endif
120 
121 #endif /* AVCODEC_ARM_VP56_ARITH_H */
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