From d2829224619866daf336141b71550e223a198838 Mon Sep 17 00:00:00 2001 From: Florian Fainelli Date: Wed, 17 Jun 2009 16:28:38 -0700 Subject: [PATCH] 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 Cc: Sergei Shtylyov Cc: Takashi Iwai Cc: Simon Horman Cc: Julius Volz Cc: David S. Miller Cc: Patrick McHardy Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/gcd.h | 8 ++++++++ lib/Makefile | 2 +- lib/gcd.c | 18 ++++++++++++++++++ 3 files changed, 27 insertions(+), 1 deletion(-) create mode 100644 include/linux/gcd.h create mode 100644 lib/gcd.c diff --git a/include/linux/gcd.h b/include/linux/gcd.h new file mode 100644 index 00000000000..69f5e8a01ba --- /dev/null +++ b/include/linux/gcd.h @@ -0,0 +1,8 @@ +#ifndef _GCD_H +#define _GCD_H + +#include + +unsigned long gcd(unsigned long a, unsigned long b) __attribute_const__; + +#endif /* _GCD_H */ diff --git a/lib/Makefile b/lib/Makefile index 8e9bcf9d326..b6d1857bbf0 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -21,7 +21,7 @@ lib-y += kobject.o kref.o klist.o obj-y += bcd.o div64.o sort.o parser.o halfmd4.o debug_locks.o random32.o \ bust_spinlocks.o hexdump.o kasprintf.o bitmap.o scatterlist.o \ - string_helpers.o + string_helpers.o gcd.o ifeq ($(CONFIG_DEBUG_KOBJECT),y) CFLAGS_kobject.o += -DDEBUG 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 +#include +#include + +/* 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);