include/linux/math64.h

   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
  11 /**
  12  * div_u64_rem - unsigned 64bit divide with 32bit divisor with remainder
  13  *
  14  * This is commonly provided by 32bit archs to provide an optimized 64bit
  15  * divide.
  16  */
  17 static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder)
  18 {
  19         *remainder = dividend % divisor;
  20         return dividend / divisor;
  21 }
  22
  23 /**
  24  * div_s64_rem - signed 64bit divide with 32bit divisor with remainder
  25  */
  26 static inline s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder)
  27 {
  28         *remainder = dividend % divisor;
  29         return dividend / divisor;
  30 }
  31
  32 /**
  33  * div64_u64_rem - unsigned 64bit divide with 64bit divisor
  34  */
  35 static inline u64 div64_u64_rem(u64 dividend, u64 divisor, u64 *remainder)
  36 {
  37         *remainder = dividend % divisor;
  38         return dividend / divisor;
  39 }
  40
  41 /**
  42  * div64_u64 - unsigned 64bit divide with 64bit divisor
  43  */
  44 static inline u64 div64_u64(u64 dividend, u64 divisor)
  45 {
  46         return dividend / divisor;
  47 }
  48
  49 /**
  50  * div64_s64 - signed 64bit divide with 64bit divisor
  51  */
  52 static inline s64 div64_s64(s64 dividend, s64 divisor)
  53 {
  54         return dividend / divisor;
  55 }
  56
  57 #elif BITS_PER_LONG == 32
  58
  59 #define div64_long(x,y) div_s64((x),(y))
  60
  61 #ifndef div_u64_rem
  62 static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder)
  63 {
  64         *remainder = do_div(dividend, divisor);
  65         return dividend;
  66 }
  67 #endif
  68
  69 #ifndef div_s64_rem
  70 extern s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder);
  71 #endif
  72
  73 #ifndef div64_u64_rem
  74 extern u64 div64_u64_rem(u64 dividend, u64 divisor, u64 *remainder);
  75 #endif
  76
  77 #ifndef div64_u64
  78 static inline u64 div64_u64(u64 dividend, u64 divisor)
  79 {
  80         u64 remainder;
  81         return div64_u64_rem(dividend, divisor, &remainder);
  82 }
  83 #endif
  84
  85 #ifndef div64_s64
  86 extern s64 div64_s64(s64 dividend, s64 divisor);
  87 #endif
  88
  89 #endif /* BITS_PER_LONG */
  90
  91 /**
  92  * div_u64 - unsigned 64bit divide with 32bit divisor
  93  *
  94  * This is the most common 64bit divide and should be used if possible,
  95  * as many 32bit archs can optimize this variant better than a full 64bit
  96  * divide.
  97  */
  98 #ifndef div_u64
  99 static inline u64 div_u64(u64 dividend, u32 divisor)
 100 {
 101         u32 remainder;
 102         return div_u64_rem(dividend, divisor, &remainder);
 103 }
 104 #endif
 105
 106 /**
 107  * div_s64 - signed 64bit divide with 32bit divisor
 108  */
 109 #ifndef div_s64
 110 static inline s64 div_s64(s64 dividend, s32 divisor)
 111 {
 112         s32 remainder;
 113         return div_s64_rem(dividend, divisor, &remainder);
 114 }
 115 #endif
 116
 117 u32 iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder);
 118
 119 static __always_inline u32
 120 __iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder)
 121 {
 122         u32 ret = 0;
 123
 124         while (dividend >= divisor) {
 125                 /* The following asm() prevents the compiler from
 126                    optimising this loop into a modulo operation.  */
 127                 asm("" : "+rm"(dividend));
 128
 129                 dividend -= divisor;
 130                 ret++;
 131         }
 132
 133         *remainder = dividend;
 134
 135         return ret;
 136 }
 137
 138 #endif /* _LINUX_MATH64_H */