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math64.h
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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 #define div64_long(x,y) div64_s64((x),(y))
10 
17 static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder)
18 {
19  *remainder = dividend % divisor;
20  return dividend / divisor;
21 }
22 
26 static inline s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder)
27 {
28  *remainder = dividend % divisor;
29  return dividend / divisor;
30 }
31 
35 static inline u64 div64_u64(u64 dividend, u64 divisor)
36 {
37  return dividend / divisor;
38 }
39 
43 static inline s64 div64_s64(s64 dividend, s64 divisor)
44 {
45  return dividend / divisor;
46 }
47 
48 #elif BITS_PER_LONG == 32
49 
50 #define div64_long(x,y) div_s64((x),(y))
51 
52 #ifndef div_u64_rem
53 static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder)
54 {
55  *remainder = do_div(dividend, divisor);
56  return dividend;
57 }
58 #endif
59 
60 #ifndef div_s64_rem
61 extern s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder);
62 #endif
63 
64 #ifndef div64_u64
65 extern u64 div64_u64(u64 dividend, u64 divisor);
66 #endif
67 
68 #ifndef div64_s64
69 extern s64 div64_s64(s64 dividend, s64 divisor);
70 #endif
71 
72 #endif /* BITS_PER_LONG */
73 
81 #ifndef div_u64
82 static inline u64 div_u64(u64 dividend, u32 divisor)
83 {
84  u32 remainder;
85  return div_u64_rem(dividend, divisor, &remainder);
86 }
87 #endif
88 
92 #ifndef div_s64
93 static inline s64 div_s64(s64 dividend, s32 divisor)
94 {
95  s32 remainder;
96  return div_s64_rem(dividend, divisor, &remainder);
97 }
98 #endif
99 
100 u32 iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder);
101 
102 static __always_inline u32
103 __iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder)
104 {
105  u32 ret = 0;
106 
107  while (dividend >= divisor) {
108  /* The following asm() prevents the compiler from
109  optimising this loop into a modulo operation. */
110  asm("" : "+rm"(dividend));
111 
112  dividend -= divisor;
113  ret++;
114  }
115 
116  *remainder = dividend;
117 
118  return ret;
119 }
120 
121 #endif /* _LINUX_MATH64_H */