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smg_comms_c_wrappers    1 /* mpi-gcd.c  -  MPI functions
smg_comms_c_wrappers    2  * Modified by No Such Labs. (C) 2015. See README.
smg_comms_c_wrappers    3  *
smg_comms_c_wrappers    4  * This file was originally part of Gnu Privacy Guard (GPG), ver. 1.4.10,
smg_comms_c_wrappers    5  * SHA256(gnupg-1.4.10.tar.gz):
smg_comms_c_wrappers    6  *        0bfd74660a2f6cedcf7d8256db4a63c996ffebbcdc2cf54397bfb72878c5a85a
smg_comms_c_wrappers    7  * (C) 1994-2005 Free Software Foundation, Inc.
smg_comms_c_wrappers    8  *
smg_comms_c_wrappers    9  * This program is free software: you can redistribute it and/or modify
smg_comms_c_wrappers   10  * it under the terms of the GNU General Public License as published by
smg_comms_c_wrappers   11  * the Free Software Foundation, either version 3 of the License, or
smg_comms_c_wrappers   12  * (at your option) any later version.
smg_comms_c_wrappers   13  *
smg_comms_c_wrappers   14  * This program is distributed in the hope that it will be useful,
smg_comms_c_wrappers   15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
smg_comms_c_wrappers   16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
smg_comms_c_wrappers   17  * GNU General Public License for more details.
smg_comms_c_wrappers   18  *
smg_comms_c_wrappers   19  * You should have received a copy of the GNU General Public License
smg_comms_c_wrappers   20  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
smg_comms_c_wrappers   21  */
smg_comms_c_wrappers   22 
smg_comms_c_wrappers   23 #include <stdio.h>
smg_comms_c_wrappers   24 #include <stdlib.h>
smg_comms_c_wrappers   25 
smg_comms_c_wrappers   26 #include "knobs.h"
smg_comms_c_wrappers   27 #include "mpi-internal.h"
smg_comms_c_wrappers   28 
smg_comms_c_wrappers   29 /****************
smg_comms_c_wrappers   30  * Find the greatest common divisor G of A and B.
smg_comms_c_wrappers   31  * Return: true if this 1, false in all other cases
smg_comms_c_wrappers   32  */
smg_comms_c_wrappers   33 int
smg_comms_c_wrappers   34 mpi_gcd( MPI g, MPI xa, MPI xb )
smg_comms_c_wrappers   35 {
smg_comms_c_wrappers   36     MPI a, b;
smg_comms_c_wrappers   37 
smg_comms_c_wrappers   38     a = mpi_copy(xa);
smg_comms_c_wrappers   39     b = mpi_copy(xb);
smg_comms_c_wrappers   40 
smg_comms_c_wrappers   41     /* TAOCP Vol II, 4.5.2, Algorithm A */
smg_comms_c_wrappers   42     a->sign = 0;
smg_comms_c_wrappers   43     b->sign = 0;
smg_comms_c_wrappers   44     while( mpi_cmp_ui( b, 0 ) ) {
smg_comms_c_wrappers   45 	mpi_fdiv_r( g, a, b ); /* g used as temorary variable */
smg_comms_c_wrappers   46 	mpi_set(a,b);
smg_comms_c_wrappers   47 	mpi_set(b,g);
smg_comms_c_wrappers   48     }
smg_comms_c_wrappers   49     mpi_set(g, a);
smg_comms_c_wrappers   50 
smg_comms_c_wrappers   51     mpi_free(a);
smg_comms_c_wrappers   52     mpi_free(b);
smg_comms_c_wrappers   53     return !mpi_cmp_ui( g, 1);
smg_comms_c_wrappers   54 }
smg_comms_c_wrappers   55 
smg_comms_c_wrappers   56 
smg_comms_c_wrappers   57