vp56_arith.h
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1 /*
2  * Copyright (C) 2010 Mans Rullgard <mans@mansr.com>
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_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 HAVE_ARMV6 && HAVE_INLINE_ASM
33 
34 #define vp56_rac_get_prob vp56_rac_get_prob_armv6
35 static inline int vp56_rac_get_prob_armv6(VP56RangeCoder *c, int pr)
36 {
37  unsigned shift = ff_vp56_norm_shift[c->high];
38  unsigned code_word = c->code_word << shift;
39  unsigned high = c->high << shift;
40  unsigned bit;
41 
42  __asm__ ("adds %3, %3, %0 \n"
43  "itt cs \n"
44  "cmpcs %7, %4 \n"
45  A("ldrcsh %2, [%4], #2 \n")
46  T("ldrhcs %2, [%4], #2 \n")
47  "rsb %0, %6, #256 \n"
48  "smlabb %0, %5, %6, %0 \n"
49  T("itttt cs \n")
50  "rev16cs %2, %2 \n"
51  T("lslcs %2, %2, %3 \n")
52  T("orrcs %1, %1, %2 \n")
53  A("orrcs %1, %1, %2, lsl %3 \n")
54  "subcs %3, %3, #16 \n"
55  "lsr %0, %0, #8 \n"
56  "cmp %1, %0, lsl #16 \n"
57  "ittte ge \n"
58  "subge %1, %1, %0, lsl #16 \n"
59  "subge %0, %5, %0 \n"
60  "movge %2, #1 \n"
61  "movlt %2, #0 \n"
62  : "=&r"(c->high), "=&r"(c->code_word), "=&r"(bit),
63  "+&r"(c->bits), "+&r"(c->buffer)
64  : "r"(high), "r"(pr), "r"(c->end - 1),
65  "0"(shift), "1"(code_word)
66  : "cc");
67 
68  return bit;
69 }
70 
71 #define vp56_rac_get_prob_branchy vp56_rac_get_prob_branchy_armv6
72 static inline int vp56_rac_get_prob_branchy_armv6(VP56RangeCoder *c, int pr)
73 {
74  unsigned shift = ff_vp56_norm_shift[c->high];
75  unsigned code_word = c->code_word << shift;
76  unsigned high = c->high << shift;
77  unsigned low;
78  unsigned tmp;
79 
80  __asm__ ("adds %3, %3, %0 \n"
81  "itt cs \n"
82  "cmpcs %7, %4 \n"
83  A("ldrcsh %2, [%4], #2 \n")
84  T("ldrhcs %2, [%4], #2 \n")
85  "rsb %0, %6, #256 \n"
86  "smlabb %0, %5, %6, %0 \n"
87  T("itttt cs \n")
88  "rev16cs %2, %2 \n"
89  T("lslcs %2, %2, %3 \n")
90  T("orrcs %1, %1, %2 \n")
91  A("orrcs %1, %1, %2, lsl %3 \n")
92  "subcs %3, %3, #16 \n"
93  "lsr %0, %0, #8 \n"
94  "lsl %2, %0, #16 \n"
95  : "=&r"(low), "+&r"(code_word), "=&r"(tmp),
96  "+&r"(c->bits), "+&r"(c->buffer)
97  : "r"(high), "r"(pr), "r"(c->end - 1), "0"(shift)
98  : "cc");
99 
100  if (code_word >= tmp) {
101  c->high = high - low;
102  c->code_word = code_word - tmp;
103  return 1;
104  }
105 
106  c->high = low;
107  c->code_word = code_word;
108  return 0;
109 }
110 
111 #endif
112 
113 #endif /* AVCODEC_ARM_VP56_ARITH_H */