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()
35 		a >>= __ffs(a);  in gcd()
36 		if (a == 1)  in gcd()
38 		if (a == b)  in gcd()
39 			return a << __ffs(r);  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()
66 		while (!(a & r))  in gcd()
67 			a >>= 1;  in gcd()
68 		if (a == r)  in gcd()
70 		if (a == b)  in gcd()
71 			return a;  in gcd()
73 		if (a < b)  in gcd()
74 			swap(a, b);  in gcd()
75 		a -= b;  in gcd()
76 		a >>= 1;  in gcd()
77 		if (a & r)  in gcd()
78 			a += b;  in gcd()
79 		a >>= 1;  in gcd()