systat.1: Improve a bit.
[dragonfly.git] / sys / dev / drm / include / linux / math64.h
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1/*-
2 * Copyright (c) 2007 Cisco Systems, Inc. All rights reserved.
3 * Copyright (c) 2014 Mellanox Technologies, Ltd. All rights reserved.
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice unmodified, this list of conditions, and the following
11 * disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28#ifndef _LINUX_MATH64_H
29#define _LINUX_MATH64_H
30
31#include <linux/types.h>
32#include <linux/bitops.h>
33
34#if BITS_PER_LONG == 64
35
36# define do_div(n, base) ({ \
37 uint32_t __base = (base); \
38 uint32_t __rem; \
39 __rem = ((uint64_t)(n)) % __base; \
40 (n) = ((uint64_t)(n)) / __base; \
41 __rem; \
42})
43
44/**
45* div_u64_rem - unsigned 64bit divide with 32bit divisor with remainder
46*
47* This is commonly provided by 32bit archs to provide an optimized 64bit
48* divide.
49*/
50static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder)
51{
52 *remainder = dividend % divisor;
53 return dividend / divisor;
54}
55
56
57#elif BITS_PER_LONG == 32
58
59static uint32_t __div64_32(uint64_t *n, uint32_t base)
60{
61 uint64_t rem = *n;
62 uint64_t b = base;
63 uint64_t res, d = 1;
64 uint32_t high = rem >> 32;
65
66 /* Reduce the thing a bit first */
67 res = 0;
68 if (high >= base) {
69 high /= base;
70 res = (uint64_t) high << 32;
71 rem -= (uint64_t) (high*base) << 32;
72 }
73
74 while ((int64_t)b > 0 && b < rem) {
75 b = b+b;
76 d = d+d;
77 }
78
79 do {
80 if (rem >= b) {
81 rem -= b;
82 res += d;
83 }
84 b >>= 1;
85 d >>= 1;
86 } while (d);
87
88 *n = res;
89 return rem;
90}
91
92# define do_div(n, base) ({ \
93 uint32_t __base = (base); \
94 uint32_t __rem; \
95 (void)(((typeof((n)) *)0) == ((uint64_t *)0)); \
96 if (likely(((n) >> 32) == 0)) { \
97 __rem = (uint32_t)(n) % __base; \
98 (n) = (uint32_t)(n) / __base; \
99 } else \
100 __rem = __div64_32(&(n), __base); \
101 __rem; \
102})
103
104#ifndef div_u64_rem
105static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder)
106{
107 *remainder = do_div(dividend, divisor);
108 return dividend;
109}
110#endif
111
112#endif /* BITS_PER_LONG */
113
114
115
116/**
117 ** div_u64 - unsigned 64bit divide with 32bit divisor
118 **
119 ** This is the most common 64bit divide and should be used if possible,
120 ** as many 32bit archs can optimize this variant better than a full 64bit
121 ** divide.
122 * */
123#ifndef div_u64
124
125static inline u64 div_u64(u64 dividend, u32 divisor)
126{
127 u32 remainder;
128 return div_u64_rem(dividend, divisor, &remainder);
129}
130#endif
131
132#endif /* _LINUX_MATH64_H */