mpi-gcd.c
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mpi-gcd.c
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	/* mpi-gcd.c - MPI functions
	* Copyright (C) 1998, 2001, 2002, 2003 Free Software Foundation, Inc.
	*
	* This file is part of Libgcrypt.
	*
	* Libgcrypt is free software; you can redistribute it and/or modify
	* it under the terms of the GNU Lesser General Public License as
	* published by the Free Software Foundation; either version 2.1 of
	* the License, or (at your option) any later version.
	*
	* Libgcrypt is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU Lesser General Public License for more details.
	*
	* You should have received a copy of the GNU Lesser General Public
	* License along with this program; if not, see <https://www.gnu.org/licenses/>.
	* SPDX-License-Identifier: LGPL-2.1-or-later
	*/

	#include <config.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include "mpi-internal.h"

	/****************
	* Find the greatest common divisor G of A and B.
	* Return: true if this 1, false in all other cases
	*/
	int
	_gcry_mpi_gcd (gcry_mpi_t g, gcry_mpi_t xa, gcry_mpi_t xb)
	{
	gcry_mpi_t a, b;

	a = mpi_copy(xa);
	b = mpi_copy(xb);

	/* TAOCP Vol II, 4.5.2, Algorithm A */
	a->sign = 0;
	b->sign = 0;
	while (mpi_cmp_ui (b, 0))
	{
	_gcry_mpi_fdiv_r( g, a, b ); /* G is used as temporary variable. */
	mpi_set(a,b);
	mpi_set(b,g);
	}
	mpi_set(g, a);

	mpi_free(a);
	mpi_free(b);
	return !mpi_cmp_ui( g, 1);
	}