diff options
| -rw-r--r-- | include/linux/gcd.h | 8 | ||||
| -rw-r--r-- | include/linux/kernel.h | 5 | ||||
| -rw-r--r-- | lib/Makefile | 1 | ||||
| -rw-r--r-- | lib/gcd.c | 18 |
4 files changed, 32 insertions, 0 deletions
diff --git a/include/linux/gcd.h b/include/linux/gcd.h new file mode 100644 index 0000000000..0ac262162d --- /dev/null +++ b/include/linux/gcd.h @@ -0,0 +1,8 @@ +#ifndef _GCD_H +#define _GCD_H + +#include <linux/kernel.h> + +unsigned long gcd(unsigned long a, unsigned long b) __attribute_const__; + +#endif /* _GCD_H */ diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 3f2644cf65..5b6b448395 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -257,5 +257,10 @@ static inline char *hex_byte_pack_upper(char *buf, u8 byte) const typeof( ((type *)0)->member ) *__mptr = (ptr); \ (type *)( (char *)__mptr - offsetof(type,member) );}) +/* + * swap - swap value of @a and @b + */ +#define swap(a, b) \ + do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0) #endif /* _LINUX_KERNEL_H */ diff --git a/lib/Makefile b/lib/Makefile index 226570a7e6..1684649dd5 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -51,3 +51,4 @@ obj-$(CONFIG_STMP_DEVICE) += stmp-device.o obj-y += wchar.o obj-y += libfile.o obj-y += bitmap.o +obj-y += gcd.o diff --git a/lib/gcd.c b/lib/gcd.c new file mode 100644 index 0000000000..86bdba9112 --- /dev/null +++ b/lib/gcd.c @@ -0,0 +1,18 @@ +#include <linux/gcd.h> + +/* Greatest common divisor */ +unsigned long gcd(unsigned long a, unsigned long b) +{ + unsigned long r; + + if (a < b) + swap(a, b); + + if (!b) + return a; + while ((r = a % b) != 0) { + a = b; + b = r; + } + return b; +} |