diff options
Diffstat (limited to 'src/lib/clog2.c')
-rw-r--r-- | src/lib/clog2.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/src/lib/clog2.c b/src/lib/clog2.c new file mode 100644 index 0000000000..092b49c821 --- /dev/null +++ b/src/lib/clog2.c @@ -0,0 +1,18 @@ +#include <console/console.h> + +unsigned long log2(unsigned long x) +{ + // assume 8 bits per byte. + unsigned long i = 1 << (sizeof(x)*8 - 1); + unsigned long pow = sizeof(x) * 8 - 1; + + if (! x) { + printk_warning("%s called with invalid parameter of 0\n", + __FUNCTION__); + return -1; + } + for(; i > x; i >>= 1, pow--) + ; + + return pow; +} |