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/mont/fp_montgomery_calc_normalization.c
- Committer:
- MiniTLS
- Date:
- 2014-06-10
- Revision:
- 4:cbaf466d717d
- Parent:
- 0:35aa5be3b78d
File content as of revision 4:cbaf466d717d:
/* TomsFastMath, a fast ISO C bignum library. * * This project is meant to fill in where LibTomMath * falls short. That is speed ;-) * * This project is public domain and free for all purposes. * * Tom St Denis, tomstdenis@gmail.com */ #include <tfm.h> /* computes a = B**n mod b without division or multiplication useful for * normalizing numbers in a Montgomery system. */ void fp_montgomery_calc_normalization(fp_int *a, fp_int *b) { int x, bits; /* how many bits of last digit does b use */ bits = fp_count_bits (b) % DIGIT_BIT; if (!bits) bits = DIGIT_BIT; /* compute A = B^(n-1) * 2^(bits-1) */ if (b->used > 1) { fp_2expt (a, (b->used - 1) * DIGIT_BIT + bits - 1); } else { fp_set(a, 1); bits = 1; } /* now compute C = A * B mod b */ for (x = bits - 1; x < (int)DIGIT_BIT; x++) { fp_mul_2 (a, a); if (fp_cmp_mag (a, b) != FP_LT) { s_fp_sub (a, b, a); } } } /* $Source: /cvs/libtom/tomsfastmath/src/mont/fp_montgomery_calc_normalization.c,v $ */ /* $Revision: 1.1 $ */ /* $Date: 2006/12/31 21:25:53 $ */