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author | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2013-10-08 19:43:00 +0400 |
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committer | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2013-10-08 19:43:00 +0400 |
commit | e3c55d406bd8df1a878546002c93db90c42be10c (patch) | |
tree | efb0ba2707c95fd7166cf1b76887c43c977e37dd /lib/div64.c | |
parent | 4d6e482675f13e33599fc3d18fc723959be0a9b6 (diff) | |
parent | d0e639c9e06d44e713170031fe05fb60ebe680af (diff) | |
download | linux-e3c55d406bd8df1a878546002c93db90c42be10c.tar.xz |
Merge tag 'v3.12-rc4' into next
Merge with mainline to bring in changes to input subsystem that were
committed through other trees.
Diffstat (limited to 'lib/div64.c')
-rw-r--r-- | lib/div64.c | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/lib/div64.c b/lib/div64.c index a163b6caef73..4382ad77777e 100644 --- a/lib/div64.c +++ b/lib/div64.c @@ -79,6 +79,46 @@ EXPORT_SYMBOL(div_s64_rem); #endif /** + * div64_u64_rem - unsigned 64bit divide with 64bit divisor and remainder + * @dividend: 64bit dividend + * @divisor: 64bit divisor + * @remainder: 64bit remainder + * + * This implementation is a comparable to algorithm used by div64_u64. + * But this operation, which includes math for calculating the remainder, + * is kept distinct to avoid slowing down the div64_u64 operation on 32bit + * systems. + */ +#ifndef div64_u64_rem +u64 div64_u64_rem(u64 dividend, u64 divisor, u64 *remainder) +{ + u32 high = divisor >> 32; + u64 quot; + + if (high == 0) { + u32 rem32; + quot = div_u64_rem(dividend, divisor, &rem32); + *remainder = rem32; + } else { + int n = 1 + fls(high); + quot = div_u64(dividend >> n, divisor >> n); + + if (quot != 0) + quot--; + + *remainder = dividend - quot * divisor; + if (*remainder >= divisor) { + quot++; + *remainder -= divisor; + } + } + + return quot; +} +EXPORT_SYMBOL(div64_u64_rem); +#endif + +/** * div64_u64 - unsigned 64bit divide with 64bit divisor * @dividend: 64bit dividend * @divisor: 64bit divisor |