| #undef DEBUG_LOG2 | |
| #ifdef DEBUG_LOG2 | |
| #include <console/console.h> | |
| #endif | |
| 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) { | |
| #ifdef DEBUG_LOG2 | |
| printk_warning("%s called with invalid parameter of 0\n", | |
| __FUNCTION__); | |
| #endif | |
| return -1; | |
| } | |
| for(; i > x; i >>= 1, pow--) | |
| ; | |
| return pow; | |
| } |