lib: add lib/gcd.c

This patch adds lib/gcd.c which contains a greatest common divider
implementation taken from sound/core/pcm_timer.c

Several usages of this new library function will be sent to subsystem
maintainers.

[akpm@linux-foundation.org: use swap() (pointed out by Joe)]
[akpm@linux-foundation.org: just add gcd.o to obj-y, remove Kconfig changes]
Signed-off-by: Florian Fainelli <florian@openwrt.org>
Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Simon Horman <horms@verge.net.au>
Cc: Julius Volz <juliusv@google.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Patrick McHardy <kaber@trash.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 18 insertions, 0 deletions

diff --git a/lib/gcd.c b/lib/gcd.c
new file mode 100644
index 00000000000..f879033d982
--- /dev/null
+++ b/lib/gcd.c
@@ -0,0 +1,18 @@
+#include <linux/kernel.h>
+#include <linux/gcd.h>
+#include <linux/module.h>
+
+/* Greatest common divisor */
+unsigned long gcd(unsigned long a, unsigned long b)
+{
+	unsigned long r;
+
+	if (a < b)
+		swap(a, b);
+	while ((r = a % b) != 0) {
+		a = b;
+		b = r;
+	}
+	return b;
+}
+EXPORT_SYMBOL_GPL(gcd);