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authorDmitry Torokhov <dmitry.torokhov@gmail.com>2013-10-08 19:43:00 +0400
committerDmitry Torokhov <dmitry.torokhov@gmail.com>2013-10-08 19:43:00 +0400
commite3c55d406bd8df1a878546002c93db90c42be10c (patch)
treeefb0ba2707c95fd7166cf1b76887c43c977e37dd /lib/div64.c
parent4d6e482675f13e33599fc3d18fc723959be0a9b6 (diff)
parentd0e639c9e06d44e713170031fe05fb60ebe680af (diff)
downloadlinux-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.c40
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