#include #include /* Assume 8 bits per byte */ #define CHAR_BIT 8 unsigned long log2(unsigned long x) { /* assume 8 bits per byte. */ unsigned long pow = sizeof(x) * CHAR_BIT - 1ULL; unsigned long i = 1ULL << pow; if (!x) { printk(BIOS_WARNING, "%s called with invalid parameter of 0\n", __func__); return -1; } for (; i > x; i >>= 1, pow--); return pow; } unsigned long log2_ceil(unsigned long x) { unsigned long pow; if (!x) return -1; pow = log2(x); if (x > (1ULL << pow)) pow++; return pow; }