#include<stdio.h>
#include<stdlib.h>

uint8_t clz(uint32_t test, uint8_t bits) {
    uint32_t cut = (test >> (32 - bits)) << (32 - bits);
    if (cut == 0) {
        return bits;
    }
    if (bits == 0) {
        return 0;
    }

    uint8_t half = bits/2;
    uint8_t result = clz(cut, half);
    if (result == half) {
        return half + clz(cut << half, half);
    } else {
        return result;
    }
}

int main() {
    int c;
    uint32_t a = 0xffffffff;
    for (c=0; c<32; c++) {
        printf("%08x %u\n", a, clz(a, 32));
        a = a >> 1;
    }
    printf("%08x %u\n", a, clz(a, 32));
    return 0;
}