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 - unsigned 64bit divide with 64bit divisor
  34  */
  35 static inline u64 div64_u64(u64 dividend, u64 divisor)
  36 {
  37         return dividend / divisor;
  38 }
  39
  40 /**
  41  * div64_s64 - signed 64bit divide with 64bit divisor
  42  */
  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
  74 /**
  75  * div_u64 - unsigned 64bit divide with 32bit divisor
  76  *
  77  * This is the most common 64bit divide and should be used if possible,
  78  * as many 32bit archs can optimize this variant better than a full 64bit
  79  * divide.
  80  */
  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
  89 /**
  90  * div_s64 - signed 64bit divide with 32bit divisor
  91  */
  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 */