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 AVUTIL_INTMATH_H
22 #define AVUTIL_INTMATH_H
23
24 #include <stdint.h>
25
26 #include "config.h"
28
29 #if ARCH_ARM
31 #endif
32
33 /**
34 * @addtogroup lavu_internal
35 * @{
36 */
37
38 #if ARCH_ARM
40 #endif
41
42 #if HAVE_FAST_CLZ && AV_GCC_VERSION_AT_LEAST(3,4)
43
44 #ifndef ff_log2
45 # define ff_log2(x) (31 - __builtin_clz((x)|1))
46 # ifndef ff_log2_16bit
47 # define ff_log2_16bit av_log2
48 # endif
49 #endif /* ff_log2 */
50
51 #endif /* AV_GCC_VERSION_AT_LEAST(3,4) */
52
54
55 #ifndef ff_log2
56 #define ff_log2 ff_log2_c
58 {
60 if (v & 0xffff0000) {
61 v >>= 16;
62 n += 16;
63 }
64 if (v & 0xff00) {
65 v >>= 8;
66 n += 8;
67 }
69
71 }
72 #endif
73
74 #ifndef ff_log2_16bit
75 #define ff_log2_16bit ff_log2_16bit_c
77 {
79 if (v & 0xff00) {
80 v >>= 8;
81 n += 8;
82 }
84
86 }
87 #endif
88
89 #define av_log2 ff_log2
90 #define av_log2_16bit ff_log2_16bit
91
92 /**
93 * @}
94 */
95
96 /**
97 * @addtogroup lavu_math
98 * @{
99 */
100
101 #if HAVE_FAST_CLZ && AV_GCC_VERSION_AT_LEAST(3,4)
102 #ifndef ff_ctz
103 #define ff_ctz(v) __builtin_ctz(v)
104 #endif
105 #endif
106
107 #ifndef ff_ctz
108 #define ff_ctz ff_ctz_c
110 {
112
113 if (v & 0x1)
114 return 0;
115
116 c = 1;
117 if (!(v & 0xffff)) {
118 v >>= 16;
119 c += 16;
120 }
121 if (!(v & 0xff)) {
122 v >>= 8;
123 c += 8;
124 }
125 if (!(v & 0xf)) {
126 v >>= 4;
127 c += 4;
128 }
129 if (!(v & 0x3)) {
130 v >>= 2;
131 c += 2;
132 }
133 c -= v & 0x1;
134
136 }
137 #endif
138
139 /**
140 * Trailing zero bit count.
141 *
142 * @param v input value. If v is 0, the result is undefined.
143 * @return the number of trailing 0-bits
144 */
146
147 /**
148 * @}
149 */
150 #endif /* AVUTIL_INTMATH_H */