#include <stdio.h>

static unsigned char lookup[256] = {
    [0x01]=1, [0x02]=2, [0x04]=3, [0x08]=4, [0x10]=5, [0x20]=6, [0x40]=7, [0x80]=8
};

unsigned log2uint(unsigned y) {
    unsigned res = lookup[(y >>  0) & 0xFF];
    if (res) return res +  0 - 1;
    res = lookup[(y >>  8) & 0xFF];
    if (res) return res +  8 - 1;
    res = lookup[(y >> 16) & 0xFF];
    if (res) return res + 16 - 1;
    res = lookup[(y >> 24) & 0xFF];
    if (res) return res + 24 - 1;
    return 0;
}

int main(void) {
	for (int i = 0 ; i != 32 ; i++) {
		printf("%d - %d - %d\n", i, (int)log2uint(1<<i), __builtin_ctz(1<<i));
	}
	return 0;
}