64bit count leading 0's in c rev2: added attribution, fixed comments

clz.c

//Count Leading Zeros (CLZ)
//Adapted from Wikipedia: http://en.wikipedia.org/wiki/Find_first_set#Algorithms
int clz (uint64_t x) {
	uint64_t t;
	int r;

	if (x == 0)
		return 0;
	t = 0x8000000000000000; 	//mask
	r = 0;				//number of zeros counter
	while ((x & t) == 0 && r < 64) {
		t = t >> 0x1;
		r ++;
	}
	return r;
}