Mercurial > hg > forks > libbpg
comparison libavutil/intmath.h @ 0:772086c29cc7
Initial import.
author | Matti Hamalainen <ccr@tnsp.org> |
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date | Wed, 16 Nov 2016 11:16:33 +0200 |
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-1:000000000000 | 0:772086c29cc7 |
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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 AVUTIL_INTMATH_H | |
22 #define AVUTIL_INTMATH_H | |
23 | |
24 #include <stdint.h> | |
25 | |
26 #include "config.h" | |
27 #include "attributes.h" | |
28 | |
29 #if ARCH_ARM | |
30 # include "arm/intmath.h" | |
31 #endif | |
32 | |
33 /** | |
34 * @addtogroup lavu_internal | |
35 * @{ | |
36 */ | |
37 | |
38 #if HAVE_FAST_CLZ | |
39 #if AV_GCC_VERSION_AT_LEAST(3,4) | |
40 #ifndef ff_log2 | |
41 # define ff_log2(x) (31 - __builtin_clz((x)|1)) | |
42 # ifndef ff_log2_16bit | |
43 # define ff_log2_16bit av_log2 | |
44 # endif | |
45 #endif /* ff_log2 */ | |
46 #elif defined( __INTEL_COMPILER ) | |
47 #ifndef ff_log2 | |
48 # define ff_log2(x) (_bit_scan_reverse(x|1)) | |
49 # ifndef ff_log2_16bit | |
50 # define ff_log2_16bit av_log2 | |
51 # endif | |
52 #endif /* ff_log2 */ | |
53 #endif | |
54 #endif /* AV_GCC_VERSION_AT_LEAST(3,4) */ | |
55 | |
56 extern const uint8_t ff_log2_tab[256]; | |
57 | |
58 #ifndef ff_log2 | |
59 #define ff_log2 ff_log2_c | |
60 #if !defined( _MSC_VER ) | |
61 static av_always_inline av_const int ff_log2_c(unsigned int v) | |
62 { | |
63 int n = 0; | |
64 if (v & 0xffff0000) { | |
65 v >>= 16; | |
66 n += 16; | |
67 } | |
68 if (v & 0xff00) { | |
69 v >>= 8; | |
70 n += 8; | |
71 } | |
72 n += ff_log2_tab[v]; | |
73 | |
74 return n; | |
75 } | |
76 #else | |
77 static av_always_inline av_const int ff_log2_c(unsigned int v) | |
78 { | |
79 unsigned long n; | |
80 _BitScanReverse(&n, v|1); | |
81 return n; | |
82 } | |
83 #define ff_log2_16bit av_log2 | |
84 #endif | |
85 #endif | |
86 | |
87 #ifndef ff_log2_16bit | |
88 #define ff_log2_16bit ff_log2_16bit_c | |
89 static av_always_inline av_const int ff_log2_16bit_c(unsigned int v) | |
90 { | |
91 int n = 0; | |
92 if (v & 0xff00) { | |
93 v >>= 8; | |
94 n += 8; | |
95 } | |
96 n += ff_log2_tab[v]; | |
97 | |
98 return n; | |
99 } | |
100 #endif | |
101 | |
102 #define av_log2 ff_log2 | |
103 #define av_log2_16bit ff_log2_16bit | |
104 | |
105 /** | |
106 * @} | |
107 */ | |
108 | |
109 /** | |
110 * @addtogroup lavu_math | |
111 * @{ | |
112 */ | |
113 | |
114 #if HAVE_FAST_CLZ | |
115 #if AV_GCC_VERSION_AT_LEAST(3,4) | |
116 #ifndef ff_ctz | |
117 #define ff_ctz(v) __builtin_ctz(v) | |
118 #endif | |
119 #elif defined( __INTEL_COMPILER ) | |
120 #ifndef ff_ctz | |
121 #define ff_ctz(v) _bit_scan_forward(v) | |
122 #endif | |
123 #endif | |
124 #endif | |
125 | |
126 #ifndef ff_ctz | |
127 #define ff_ctz ff_ctz_c | |
128 #if !defined( _MSC_VER ) | |
129 static av_always_inline av_const int ff_ctz_c(int v) | |
130 { | |
131 int c; | |
132 | |
133 if (v & 0x1) | |
134 return 0; | |
135 | |
136 c = 1; | |
137 if (!(v & 0xffff)) { | |
138 v >>= 16; | |
139 c += 16; | |
140 } | |
141 if (!(v & 0xff)) { | |
142 v >>= 8; | |
143 c += 8; | |
144 } | |
145 if (!(v & 0xf)) { | |
146 v >>= 4; | |
147 c += 4; | |
148 } | |
149 if (!(v & 0x3)) { | |
150 v >>= 2; | |
151 c += 2; | |
152 } | |
153 c -= v & 0x1; | |
154 | |
155 return c; | |
156 } | |
157 #else | |
158 static av_always_inline av_const int ff_ctz_c( int v ) | |
159 { | |
160 unsigned long c; | |
161 _BitScanForward(&c, v); | |
162 return c; | |
163 } | |
164 #endif | |
165 #endif | |
166 | |
167 /** | |
168 * Trailing zero bit count. | |
169 * | |
170 * @param v input value. If v is 0, the result is undefined. | |
171 * @return the number of trailing 0-bits | |
172 */ | |
173 int av_ctz(int v); | |
174 | |
175 /** | |
176 * @} | |
177 */ | |
178 #endif /* AVUTIL_INTMATH_H */ |