23 unsigned long gcd(unsigned long a, unsigned long b)  in gcd()  argument
25 	unsigned long r = a | b;  in gcd()
27 	if (!a || !b)  in gcd()
30 	b >>= __ffs(b);  in gcd()
31 	if (b == 1)  in gcd()
38 		if (a == b)  in gcd()
41 		if (a < b)  in gcd()
42 			swap(a, b);  in gcd()
43 		a -= b;  in gcd()
50 unsigned long gcd(unsigned long a, unsigned long b)  in gcd()  argument
52 	unsigned long r = a | b;  in gcd()
54 	if (!a || !b)  in gcd()
60 	while (!(b & r))  in gcd()
61 		b >>= 1;  in gcd()
62 	if (b == r)  in gcd()
70 		if (a == b)  in gcd()
73 		if (a < b)  in gcd()
74 			swap(a, b);  in gcd()
75 		a -= b;  in gcd()
78 			a += b;  in gcd()