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/bit/fp_div_2.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?
User | Revision | Line number | New 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 | /* b = a/2 */ |
MiniTLS | 0:35aa5be3b78d | 13 | void fp_div_2(fp_int * a, fp_int * b) |
MiniTLS | 0:35aa5be3b78d | 14 | { |
MiniTLS | 0:35aa5be3b78d | 15 | int x, oldused; |
MiniTLS | 0:35aa5be3b78d | 16 | |
MiniTLS | 0:35aa5be3b78d | 17 | oldused = b->used; |
MiniTLS | 0:35aa5be3b78d | 18 | b->used = a->used; |
MiniTLS | 0:35aa5be3b78d | 19 | { |
MiniTLS | 0:35aa5be3b78d | 20 | register fp_digit r, rr, *tmpa, *tmpb; |
MiniTLS | 0:35aa5be3b78d | 21 | |
MiniTLS | 0:35aa5be3b78d | 22 | /* source alias */ |
MiniTLS | 0:35aa5be3b78d | 23 | tmpa = a->dp + b->used - 1; |
MiniTLS | 0:35aa5be3b78d | 24 | |
MiniTLS | 0:35aa5be3b78d | 25 | /* dest alias */ |
MiniTLS | 0:35aa5be3b78d | 26 | tmpb = b->dp + b->used - 1; |
MiniTLS | 0:35aa5be3b78d | 27 | |
MiniTLS | 0:35aa5be3b78d | 28 | /* carry */ |
MiniTLS | 0:35aa5be3b78d | 29 | r = 0; |
MiniTLS | 0:35aa5be3b78d | 30 | for (x = b->used - 1; x >= 0; x--) { |
MiniTLS | 0:35aa5be3b78d | 31 | /* get the carry for the next iteration */ |
MiniTLS | 0:35aa5be3b78d | 32 | rr = *tmpa & 1; |
MiniTLS | 0:35aa5be3b78d | 33 | |
MiniTLS | 0:35aa5be3b78d | 34 | /* shift the current digit, add in carry and store */ |
MiniTLS | 0:35aa5be3b78d | 35 | *tmpb-- = (*tmpa-- >> 1) | (r << (DIGIT_BIT - 1)); |
MiniTLS | 0:35aa5be3b78d | 36 | |
MiniTLS | 0:35aa5be3b78d | 37 | /* forward carry to next iteration */ |
MiniTLS | 0:35aa5be3b78d | 38 | r = rr; |
MiniTLS | 0:35aa5be3b78d | 39 | } |
MiniTLS | 0:35aa5be3b78d | 40 | |
MiniTLS | 0:35aa5be3b78d | 41 | /* zero excess digits */ |
MiniTLS | 0:35aa5be3b78d | 42 | tmpb = b->dp + b->used; |
MiniTLS | 0:35aa5be3b78d | 43 | for (x = b->used; x < oldused; x++) { |
MiniTLS | 0:35aa5be3b78d | 44 | *tmpb++ = 0; |
MiniTLS | 0:35aa5be3b78d | 45 | } |
MiniTLS | 0:35aa5be3b78d | 46 | } |
MiniTLS | 0:35aa5be3b78d | 47 | b->sign = a->sign; |
MiniTLS | 0:35aa5be3b78d | 48 | fp_clamp (b); |
MiniTLS | 0:35aa5be3b78d | 49 | } |
MiniTLS | 0:35aa5be3b78d | 50 | |
MiniTLS | 0:35aa5be3b78d | 51 | /* $Source: /cvs/libtom/tomsfastmath/src/bit/fp_div_2.c,v $ */ |
MiniTLS | 0:35aa5be3b78d | 52 | /* $Revision: 1.1 $ */ |
MiniTLS | 0:35aa5be3b78d | 53 | /* $Date: 2006/12/31 21:25:53 $ */ |