bitwise operators for finding less than in c

Question

This is a homework assignment which requires me to come up with a function to determine if x < y, if it is I must return 1, using only bitwise o

Answer 1

I think it can be achived doing following:

1. Xor both numbers, that will give you bits that differs
2. Get the most significant bit that differs, as this one will make a difference
3. Check if that most significant bit belongs to bigger value

Code:

int less(int x, int y) {
    //Get only diffed bits
    int msb = x ^ y;
    //Get first msb bit
    msb |= (msb >>  1);
    msb |= (msb >>  2);
    msb |= (msb >>  4);
    msb |= (msb >>  8);
    msb |= (msb >> 16);
    msb = msb - (msb >> 1);
    //check if msb belongs to y;
    return !((y & msb) ^ msb);
}