1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
|
/*
* Copyright (c) 2010 Mans Rullgard <mans@mansr.com>
*
* This file is part of Libav.
*
* Libav is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* Libav is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef AVUTIL_INTMATH_H
#define AVUTIL_INTMATH_H
#include <stdint.h>
#include "config.h"
#include "attributes.h"
#if ARCH_ARM
# include "arm/intmath.h"
#endif
/**
* @addtogroup lavu_internal
* @{
*/
#if HAVE_FAST_CLZ && AV_GCC_VERSION_AT_LEAST(3,4)
#ifndef ff_log2
# define ff_log2(x) (31 - __builtin_clz((x)|1))
# ifndef ff_log2_16bit
# define ff_log2_16bit av_log2
# endif
#endif /* ff_log2 */
#ifndef ff_clz
# define ff_clz(v) __builtin_clz(v)
#endif /* ff_clz */
#endif /* AV_GCC_VERSION_AT_LEAST(3,4) */
extern const uint8_t ff_log2_tab[256];
#ifndef ff_log2
#define ff_log2 ff_log2_c
static av_always_inline av_const int ff_log2_c(unsigned int v)
{
int n = 0;
if (v & 0xffff0000) {
v >>= 16;
n += 16;
}
if (v & 0xff00) {
v >>= 8;
n += 8;
}
n += ff_log2_tab[v];
return n;
}
#endif
#ifndef ff_log2_16bit
#define ff_log2_16bit ff_log2_16bit_c
static av_always_inline av_const int ff_log2_16bit_c(unsigned int v)
{
int n = 0;
if (v & 0xff00) {
v >>= 8;
n += 8;
}
n += ff_log2_tab[v];
return n;
}
#endif
#define av_log2 ff_log2
#define av_log2_16bit ff_log2_16bit
/**
* @}
*/
/**
* @addtogroup lavu_math
* @{
*/
#if HAVE_FAST_CLZ && AV_GCC_VERSION_AT_LEAST(3,4)
#ifndef ff_ctz
#define ff_ctz(v) __builtin_ctz(v)
#endif
#endif
#ifndef ff_ctz
#define ff_ctz ff_ctz_c
static av_always_inline av_const int ff_ctz_c(int v)
{
int c;
if (v & 0x1)
return 0;
c = 1;
if (!(v & 0xffff)) {
v >>= 16;
c += 16;
}
if (!(v & 0xff)) {
v >>= 8;
c += 8;
}
if (!(v & 0xf)) {
v >>= 4;
c += 4;
}
if (!(v & 0x3)) {
v >>= 2;
c += 2;
}
c -= v & 0x1;
return c;
}
#endif
#ifndef ff_clz
#define ff_clz ff_clz_c
static av_always_inline av_const unsigned ff_clz_c(unsigned x)
{
unsigned i = sizeof(x) * 8;
while (x) {
x >>= 1;
i--;
}
return i;
}
#endif
/**
* Trailing zero bit count.
*
* @param v input value. If v is 0, the result is undefined.
* @return the number of trailing 0-bits
*/
int av_ctz(int v);
/**
* @}
*/
#endif /* AVUTIL_INTMATH_H */
|
