include/linux/calc64.h

   1 #ifndef _LINUX_CALC64_H
   2 #define _LINUX_CALC64_H
   3
   4 #include <linux/types.h>
   5 #include <asm/div64.h>
   6
   7 /*
   8  * This is a generic macro which is used when the architecture
   9  * specific div64.h does not provide a optimized one.
  10  *
  11  * The 64bit dividend is divided by the divisor (data type long), the
  12  * result is returned and the remainder stored in the variable
  13  * referenced by remainder (data type long *). In contrast to the
  14  * do_div macro the dividend is kept intact.
  15  */
  16 #ifndef div_long_long_rem
  17 #define div_long_long_rem(dividend, divisor, remainder) \
  18         do_div_llr((dividend), divisor, remainder)
  19
  20 static inline unsigned long do_div_llr(const long long dividend,
  21                                        const long divisor, long *remainder)
  22 {
  23         u64 result = dividend;
  24
  25         *(remainder) = do_div(result, divisor);
  26         return (unsigned long) result;
  27 }
  28 #endif
  29
  30 /*
  31  * Sign aware variation of the above. On some architectures a
  32  * negative dividend leads to an divide overflow exception, which
  33  * is avoided by the sign check.
  34  */
  35 static inline long div_long_long_rem_signed(const long long dividend,
  36                                             const long divisor, long *remainder)
  37 {
  38         long res;
  39
  40         if (unlikely(dividend < 0)) {
  41                 res = -div_long_long_rem(-dividend, divisor, remainder);
  42                 *remainder = -(*remainder);
  43         } else
  44                 res = div_long_long_rem(dividend, divisor, remainder);
  45
  46         return res;
  47 }
  48
  49 #endif