/*

 * Fast implementation of greatest common divisor using the binary algorithm.

 * Copyright (c) 2007 Nicholas Kain

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to

 * deal in the Software without restriction, including without limitation the

 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or

 * sell copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS

 * IN THE SOFTWARE.

 */

/* computes gcd using binary algorithm */

static int gcd(int a, int b)

{

	int s,d;

	if (!a || !b)

		return a | b;

	for (s=0; ((a|b)&1) == 0; ++s) {

		a >>= 1;

		b >>= 1;

	}

	while ((a&1) == 0)

		a >>= 1;

	do {

		while ((b&1) == 0) {

			b >>= 1;

		}

		if (a

			b -= a;

		} else {

			d = a-b;

			a = b;

			b = d;

		}

		b >>= 1;

	} while (b);

	return a << s;

}