diff options
Diffstat (limited to 'include/linux/calc64.h')
-rw-r--r-- | include/linux/calc64.h | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/include/linux/calc64.h b/include/linux/calc64.h new file mode 100644 index 000000000000..ebf4b8f38d88 --- /dev/null +++ b/include/linux/calc64.h @@ -0,0 +1,49 @@ +#ifndef _LINUX_CALC64_H +#define _LINUX_CALC64_H + +#include <linux/types.h> +#include <asm/div64.h> + +/* + * This is a generic macro which is used when the architecture + * specific div64.h does not provide a optimized one. + * + * The 64bit dividend is divided by the divisor (data type long), the + * result is returned and the remainder stored in the variable + * referenced by remainder (data type long *). In contrast to the + * do_div macro the dividend is kept intact. + */ +#ifndef div_long_long_rem +#define div_long_long_rem(dividend, divisor, remainder) \ + do_div_llr((dividend), divisor, remainder) + +static inline unsigned long do_div_llr(const long long dividend, + const long divisor, long *remainder) +{ + u64 result = dividend; + + *(remainder) = do_div(result, divisor); + return (unsigned long) result; +} +#endif + +/* + * Sign aware variation of the above. On some architectures a + * negative dividend leads to an divide overflow exception, which + * is avoided by the sign check. + */ +static inline long div_long_long_rem_signed(const long long dividend, + const long divisor, long *remainder) +{ + long res; + + if (unlikely(dividend < 0)) { + res = -div_long_long_rem(-dividend, divisor, remainder); + *remainder = -(*remainder); + } else + res = div_long_long_rem(dividend, divisor, remainder); + + return res; +} + +#endif |