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 */
div_u64_rem(u64 dividend,u32 divisor,u32 * remainder)15 static 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 */
div_s64_rem(s64 dividend,s32 divisor,s32 * remainder)24 static 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 */
div64_u64(u64 dividend,u64 divisor)33 static 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 */
div64_s64(s64 dividend,s64 divisor)41 static 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
div_u64_rem(u64 dividend,u32 divisor,u32 * remainder)49 static 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
57 extern s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder);
58 #endif
59
60 #ifndef div64_u64
61 extern u64 div64_u64(u64 dividend, u64 divisor);
62 #endif
63
64 #ifndef div64_s64
65 extern 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
div_u64(u64 dividend,u32 divisor)78 static 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
div_s64(s64 dividend,s32 divisor)89 static inline s64 div_s64(s64 dividend, s32 divisor)
90 {
91 s32 remainder;
92 return div_s64_rem(dividend, divisor, &remainder);
93 }
94 #endif
95
96 u32 iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder);
97
98 static __always_inline u32
__iter_div_u64_rem(u64 dividend,u32 divisor,u64 * remainder)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 */
118