1 /*-
2 * Copyright (c) 2010 Isilon Systems, Inc.
3 * Copyright (c) 2010 iX Systems, Inc.
4 * Copyright (c) 2010 Panasas, Inc.
5 * Copyright (c) 2013-2015 Mellanox Technologies, Ltd.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice unmodified, this list of conditions, and the following
13 * disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29 #ifndef _LINUXKPI_LINUX_LOG2_H_
30 #define _LINUXKPI_LINUX_LOG2_H_
31
32 #include <linux/types.h>
33
34 #include <sys/libkern.h>
35
36 static inline unsigned long
roundup_pow_of_two(unsigned long x)37 roundup_pow_of_two(unsigned long x)
38 {
39 return (1UL << flsl(x - 1));
40 }
41
42 static inline int
is_power_of_2(unsigned long n)43 is_power_of_2(unsigned long n)
44 {
45 return (n == roundup_pow_of_two(n));
46 }
47
48 static inline unsigned long
rounddown_pow_of_two(unsigned long x)49 rounddown_pow_of_two(unsigned long x)
50 {
51 return (1UL << (flsl(x) - 1));
52 }
53
54 #define ilog2(n) \
55 ( \
56 __builtin_constant_p(n) ? ( \
57 (n) < 1 ? -1 : \
58 (n) & (1ULL << 63) ? 63 : \
59 (n) & (1ULL << 62) ? 62 : \
60 (n) & (1ULL << 61) ? 61 : \
61 (n) & (1ULL << 60) ? 60 : \
62 (n) & (1ULL << 59) ? 59 : \
63 (n) & (1ULL << 58) ? 58 : \
64 (n) & (1ULL << 57) ? 57 : \
65 (n) & (1ULL << 56) ? 56 : \
66 (n) & (1ULL << 55) ? 55 : \
67 (n) & (1ULL << 54) ? 54 : \
68 (n) & (1ULL << 53) ? 53 : \
69 (n) & (1ULL << 52) ? 52 : \
70 (n) & (1ULL << 51) ? 51 : \
71 (n) & (1ULL << 50) ? 50 : \
72 (n) & (1ULL << 49) ? 49 : \
73 (n) & (1ULL << 48) ? 48 : \
74 (n) & (1ULL << 47) ? 47 : \
75 (n) & (1ULL << 46) ? 46 : \
76 (n) & (1ULL << 45) ? 45 : \
77 (n) & (1ULL << 44) ? 44 : \
78 (n) & (1ULL << 43) ? 43 : \
79 (n) & (1ULL << 42) ? 42 : \
80 (n) & (1ULL << 41) ? 41 : \
81 (n) & (1ULL << 40) ? 40 : \
82 (n) & (1ULL << 39) ? 39 : \
83 (n) & (1ULL << 38) ? 38 : \
84 (n) & (1ULL << 37) ? 37 : \
85 (n) & (1ULL << 36) ? 36 : \
86 (n) & (1ULL << 35) ? 35 : \
87 (n) & (1ULL << 34) ? 34 : \
88 (n) & (1ULL << 33) ? 33 : \
89 (n) & (1ULL << 32) ? 32 : \
90 (n) & (1ULL << 31) ? 31 : \
91 (n) & (1ULL << 30) ? 30 : \
92 (n) & (1ULL << 29) ? 29 : \
93 (n) & (1ULL << 28) ? 28 : \
94 (n) & (1ULL << 27) ? 27 : \
95 (n) & (1ULL << 26) ? 26 : \
96 (n) & (1ULL << 25) ? 25 : \
97 (n) & (1ULL << 24) ? 24 : \
98 (n) & (1ULL << 23) ? 23 : \
99 (n) & (1ULL << 22) ? 22 : \
100 (n) & (1ULL << 21) ? 21 : \
101 (n) & (1ULL << 20) ? 20 : \
102 (n) & (1ULL << 19) ? 19 : \
103 (n) & (1ULL << 18) ? 18 : \
104 (n) & (1ULL << 17) ? 17 : \
105 (n) & (1ULL << 16) ? 16 : \
106 (n) & (1ULL << 15) ? 15 : \
107 (n) & (1ULL << 14) ? 14 : \
108 (n) & (1ULL << 13) ? 13 : \
109 (n) & (1ULL << 12) ? 12 : \
110 (n) & (1ULL << 11) ? 11 : \
111 (n) & (1ULL << 10) ? 10 : \
112 (n) & (1ULL << 9) ? 9 : \
113 (n) & (1ULL << 8) ? 8 : \
114 (n) & (1ULL << 7) ? 7 : \
115 (n) & (1ULL << 6) ? 6 : \
116 (n) & (1ULL << 5) ? 5 : \
117 (n) & (1ULL << 4) ? 4 : \
118 (n) & (1ULL << 3) ? 3 : \
119 (n) & (1ULL << 2) ? 2 : \
120 (n) & (1ULL << 1) ? 1 : \
121 (n) & (1ULL << 0) ? 0 : \
122 -1) : \
123 (sizeof(n) <= 4) ? \
124 fls((u32)(n)) - 1 : flsll((u64)(n)) - 1 \
125 )
126
127 #define order_base_2(x) ilog2(roundup_pow_of_two(x))
128
129 #endif /* _LINUXKPI_LINUX_LOG2_H_ */
130