Donatien Garnier / MiniTLS-GPL

A super trimmed down TLS stack, GPL licensed

Dependents:   MiniTLS-HTTPS-Example

MiniTLS - A super trimmed down TLS/SSL Library for embedded devices Author: Donatien Garnier Copyright (C) 2013-2014 AppNearMe Ltd

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program 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 General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.

math/numtheory/fp_gcd.c@0:35aa5be3b78d, 2014-06-06 (annotated)

Committer:
MiniTLS
Date:
Fri Jun 06 10:49:02 2014 +0000
Revision:
0:35aa5be3b78d
Initial commit

Who changed what in which revision?

UserRevisionLine numberNew contents of line
MiniTLS 0:35aa5be3b78d 1 /* TomsFastMath, a fast ISO C bignum library.
MiniTLS 0:35aa5be3b78d 2 *
MiniTLS 0:35aa5be3b78d 3 * This project is meant to fill in where LibTomMath
MiniTLS 0:35aa5be3b78d 4 * falls short. That is speed ;-)
MiniTLS 0:35aa5be3b78d 5 *
MiniTLS 0:35aa5be3b78d 6 * This project is public domain and free for all purposes.
MiniTLS 0:35aa5be3b78d 7 *
MiniTLS 0:35aa5be3b78d 8 * Tom St Denis, tomstdenis@gmail.com
MiniTLS 0:35aa5be3b78d 9 */
MiniTLS 0:35aa5be3b78d 10 #include <tfm.h>
MiniTLS 0:35aa5be3b78d 11
MiniTLS 0:35aa5be3b78d 12 /* c = (a, b) */
MiniTLS 0:35aa5be3b78d 13 void fp_gcd(fp_int *a, fp_int *b, fp_int *c)
MiniTLS 0:35aa5be3b78d 14 {
MiniTLS 0:35aa5be3b78d 15 fp_int u, v, r;
MiniTLS 0:35aa5be3b78d 16
MiniTLS 0:35aa5be3b78d 17 /* either zero than gcd is the largest */
MiniTLS 0:35aa5be3b78d 18 if (fp_iszero (a) == 1 && fp_iszero (b) == 0) {
MiniTLS 0:35aa5be3b78d 19 fp_abs (b, c);
MiniTLS 0:35aa5be3b78d 20 return;
MiniTLS 0:35aa5be3b78d 21 }
MiniTLS 0:35aa5be3b78d 22 if (fp_iszero (a) == 0 && fp_iszero (b) == 1) {
MiniTLS 0:35aa5be3b78d 23 fp_abs (a, c);
MiniTLS 0:35aa5be3b78d 24 return;
MiniTLS 0:35aa5be3b78d 25 }
MiniTLS 0:35aa5be3b78d 26
MiniTLS 0:35aa5be3b78d 27 /* optimized. At this point if a == 0 then
MiniTLS 0:35aa5be3b78d 28 * b must equal zero too
MiniTLS 0:35aa5be3b78d 29 */
MiniTLS 0:35aa5be3b78d 30 if (fp_iszero (a) == 1) {
MiniTLS 0:35aa5be3b78d 31 fp_zero(c);
MiniTLS 0:35aa5be3b78d 32 return;
MiniTLS 0:35aa5be3b78d 33 }
MiniTLS 0:35aa5be3b78d 34
MiniTLS 0:35aa5be3b78d 35 /* sort inputs */
MiniTLS 0:35aa5be3b78d 36 if (fp_cmp_mag(a, b) != FP_LT) {
MiniTLS 0:35aa5be3b78d 37 fp_init_copy(&u, a);
MiniTLS 0:35aa5be3b78d 38 fp_init_copy(&v, b);
MiniTLS 0:35aa5be3b78d 39 } else {
MiniTLS 0:35aa5be3b78d 40 fp_init_copy(&u, b);
MiniTLS 0:35aa5be3b78d 41 fp_init_copy(&v, a);
MiniTLS 0:35aa5be3b78d 42 }
MiniTLS 0:35aa5be3b78d 43
MiniTLS 0:35aa5be3b78d 44 fp_zero(&r);
MiniTLS 0:35aa5be3b78d 45 while (fp_iszero(&v) == FP_NO) {
MiniTLS 0:35aa5be3b78d 46 fp_mod(&u, &v, &r);
MiniTLS 0:35aa5be3b78d 47 fp_copy(&v, &u);
MiniTLS 0:35aa5be3b78d 48 fp_copy(&r, &v);
MiniTLS 0:35aa5be3b78d 49 }
MiniTLS 0:35aa5be3b78d 50 fp_copy(&u, c);
MiniTLS 0:35aa5be3b78d 51 }
MiniTLS 0:35aa5be3b78d 52
MiniTLS 0:35aa5be3b78d 53 /* $Source: /cvs/libtom/tomsfastmath/src/numtheory/fp_gcd.c,v $ */
MiniTLS 0:35aa5be3b78d 54 /* $Revision: 1.1 $ */
MiniTLS 0:35aa5be3b78d 55 /* $Date: 2007/01/24 21:25:19 $ */