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1#ifndef _LINUX_MATH64_H
2#define _LINUX_MATH64_H
3
4#include <linux/types.h>
5#include <asm/div64.h>
6
7#if BITS_PER_LONG == 64
8
9/**
10 * div_u64_rem - unsigned 64bit divide with 32bit divisor with remainder
11 *
12 * This is commonly provided by 32bit archs to provide an optimized 64bit
13 * divide.
14 */
15static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder)
16{
17 *remainder = dividend % divisor;
18 return dividend / divisor;
19}
20
21/**
22 * div_s64_rem - signed 64bit divide with 32bit divisor with remainder
23 */
24static inline s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder)
25{
26 *remainder = dividend % divisor;
27 return dividend / divisor;
28}
29
30/**
31 * div64_u64 - unsigned 64bit divide with 64bit divisor
32 */
33static inline u64 div64_u64(u64 dividend, u64 divisor)
34{
35 return dividend / divisor;
36}
37
38/**
39 * div64_s64 - signed 64bit divide with 64bit divisor
40 */
41static inline s64 div64_s64(s64 dividend, s64 divisor)
42{
43 return dividend / divisor;
44}
45
46#elif BITS_PER_LONG == 32
47
48#ifndef div_u64_rem
49static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder)
50{
51 *remainder = do_div(dividend, divisor);
52 return dividend;
53}
54#endif
55
56#ifndef div_s64_rem
57extern s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder);
58#endif
59
60#ifndef div64_u64
61extern u64 div64_u64(u64 dividend, u64 divisor);
62#endif
63
64#ifndef div64_s64
65extern s64 div64_s64(s64 dividend, s64 divisor);
66#endif
67
68#endif /* BITS_PER_LONG */
69
70/**
71 * div_u64 - unsigned 64bit divide with 32bit divisor
72 *
73 * This is the most common 64bit divide and should be used if possible,
74 * as many 32bit archs can optimize this variant better than a full 64bit
75 * divide.
76 */
77#ifndef div_u64
78static inline u64 div_u64(u64 dividend, u32 divisor)
79{
80 u32 remainder;
81 return div_u64_rem(dividend, divisor, &remainder);
82}
83#endif
84
85/**
86 * div_s64 - signed 64bit divide with 32bit divisor
87 */
88#ifndef div_s64
89static inline s64 div_s64(s64 dividend, s32 divisor)
90{
91 s32 remainder;
92 return div_s64_rem(dividend, divisor, &remainder);
93}
94#endif
95
96u32 iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder);
97
98static __always_inline u32
99__iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder)
100{
101 u32 ret = 0;
102
103 while (dividend >= divisor) {
104 /* The following asm() prevents the compiler from
105 optimising this loop into a modulo operation. */
106 asm("" : "+rm"(dividend));
107
108 dividend -= divisor;
109 ret++;
110 }
111
112 *remainder = dividend;
113
114 return ret;
115}
116
117#endif /* _LINUX_MATH64_H */