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
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
|
/* ----------------------------------------------------------------------- *
*
* Copyright 1996-2017 The NASM Authors - All Rights Reserved
* See the file AUTHORS included with the NASM distribution for
* the specific copyright holders.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following
* conditions are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* ----------------------------------------------------------------------- */
#ifndef ILOG2_H
#define ILOG2_H
#include "compiler.h"
#ifdef ILOG2_C /* For generating the out-of-line functions */
# undef extern_inline
# define extern_inline
# define inline_prototypes
#endif
#ifdef inline_prototypes
extern unsigned int const_func ilog2_32(uint32_t v);
extern unsigned int const_func ilog2_64(uint64_t v);
extern unsigned int const_func ilog2_64(uint64_t vv);
extern int const_func alignlog2_32(uint32_t v);
extern int const_func alignlog2_64(uint64_t v);
#endif
#ifdef extern_inline
#define ROUND(v, a, w) \
do { \
if (v & (((UINT32_C(1) << w) - 1) << w)) { \
a += w; \
v >>= w; \
} \
} while (0)
#if defined(HAVE___BUILTIN_CLZ) && INT_MAX == 2147483647
extern_inline unsigned int const_func ilog2_32(uint32_t v)
{
if (!v)
return 0;
return __builtin_clz(v) ^ 31;
}
#elif defined(__GNUC__) && defined(__x86_64__)
extern_inline unsigned int const_func ilog2_32(uint32_t v)
{
unsigned int n;
__asm__("bsrl %1,%0"
: "=r" (n)
: "rm" (v), "0" (0));
return n;
}
#elif defined(__GNUC__) && defined(__i386__)
extern_inline unsigned int const_func ilog2_32(uint32_t v)
{
unsigned int n;
#ifdef __i686__
__asm__("bsrl %1,%0 ; cmovz %2,%0\n"
: "=&r" (n)
: "rm" (v), "r" (0));
#else
__asm__("bsrl %1,%0 ; jnz 1f ; xorl %0,%0\n"
"1:"
: "=&r" (n)
: "rm" (v));
#endif
return n;
}
#elif defined(HAVE__BITSCANREVERSE)
extern_inline unsigned int const_func ilog2_32(uint32_t v)
{
unsigned long ix;
return _BitScanReverse(&ix, v) ? v : 0;
}
#else
extern_inline unsigned int const_func ilog2_32(uint32_t v)
{
unsigned int p = 0;
ROUND(v, p, 16);
ROUND(v, p, 8);
ROUND(v, p, 4);
ROUND(v, p, 2);
ROUND(v, p, 1);
return p;
}
#endif
#if defined(HAVE__BUILTIN_CLZLL) && LLONG_MAX == 9223372036854775807LL
extern_inline unsigned int const_func ilog2_64(uint64_t v)
{
if (!v)
return 0;
return __builtin_clzll(v) ^ 63;
}
#elif defined(__GNUC__) && defined(__x86_64__)
extern_inline unsigned int const_func ilog2_64(uint64_t v)
{
uint64_t n;
__asm__("bsrq %1,%0"
: "=r" (n)
: "rm" (v), "0" (UINT64_C(0)));
return n;
}
#elif defined(HAVE__BITSCANREVERSE64)
extern_inline unsigned int const_func ilog2_64(uint64_t v)
{
unsigned long ix;
return _BitScanReverse64(&ix, v) ? ix : 0;
}
#else
extern_inline unsigned int const_func ilog2_64(uint64_t vv)
{
unsigned int p = 0;
uint32_t v;
v = vv >> 32;
if (v)
p += 32;
else
v = vv;
return p + ilog2_32(v);
}
#endif
/*
* v == 0 ? 0 : is_power2(x) ? ilog2_X(v) : -1
*/
extern_inline int const_func alignlog2_32(uint32_t v)
{
if (unlikely(v & (v-1)))
return -1; /* invalid alignment */
return ilog2_32(v);
}
extern_inline int const_func alignlog2_64(uint64_t v)
{
if (unlikely(v & (v-1)))
return -1; /* invalid alignment */
return ilog2_64(v);
}
#undef ROUND
#endif /* extern_inline */
#endif /* ILOG2_H */
|
