22 unsigned long gcd(unsigned long a, unsigned long b)  in gcd()  argument
24 	unsigned long r = a | b;  in gcd()
26 	if (!a || !b)  in gcd()
29 	b >>= __ffs(b);  in gcd()
30 	if (b == 1)  in gcd()
37 		if (a == b)  in gcd()
40 		if (a < b)  in gcd()
41 			swap(a, b);  in gcd()
42 		a -= b;  in gcd()
49 unsigned long gcd(unsigned long a, unsigned long b)  in gcd()  argument
51 	unsigned long r = a | b;  in gcd()
53 	if (!a || !b)  in gcd()
59 	while (!(b & r))  in gcd()
60 		b >>= 1;  in gcd()
61 	if (b == r)  in gcd()
69 		if (a == b)  in gcd()
72 		if (a < b)  in gcd()
73 			swap(a, b);  in gcd()
74 		a -= b;  in gcd()
77 			a += b;  in gcd()