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_cnt_lsb.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 | static const int lnz[16] = { |
MiniTLS | 0:35aa5be3b78d | 13 | 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0 |
MiniTLS | 0:35aa5be3b78d | 14 | }; |
MiniTLS | 0:35aa5be3b78d | 15 | |
MiniTLS | 0:35aa5be3b78d | 16 | /* Counts the number of lsbs which are zero before the first zero bit */ |
MiniTLS | 0:35aa5be3b78d | 17 | int fp_cnt_lsb(fp_int *a) |
MiniTLS | 0:35aa5be3b78d | 18 | { |
MiniTLS | 0:35aa5be3b78d | 19 | int x; |
MiniTLS | 0:35aa5be3b78d | 20 | fp_digit q, qq; |
MiniTLS | 0:35aa5be3b78d | 21 | |
MiniTLS | 0:35aa5be3b78d | 22 | /* easy out */ |
MiniTLS | 0:35aa5be3b78d | 23 | if (fp_iszero(a) == 1) { |
MiniTLS | 0:35aa5be3b78d | 24 | return 0; |
MiniTLS | 0:35aa5be3b78d | 25 | } |
MiniTLS | 0:35aa5be3b78d | 26 | |
MiniTLS | 0:35aa5be3b78d | 27 | /* scan lower digits until non-zero */ |
MiniTLS | 0:35aa5be3b78d | 28 | for (x = 0; x < a->used && a->dp[x] == 0; x++); |
MiniTLS | 0:35aa5be3b78d | 29 | q = a->dp[x]; |
MiniTLS | 0:35aa5be3b78d | 30 | x *= DIGIT_BIT; |
MiniTLS | 0:35aa5be3b78d | 31 | |
MiniTLS | 0:35aa5be3b78d | 32 | /* now scan this digit until a 1 is found */ |
MiniTLS | 0:35aa5be3b78d | 33 | if ((q & 1) == 0) { |
MiniTLS | 0:35aa5be3b78d | 34 | do { |
MiniTLS | 0:35aa5be3b78d | 35 | qq = q & 15; |
MiniTLS | 0:35aa5be3b78d | 36 | x += lnz[qq]; |
MiniTLS | 0:35aa5be3b78d | 37 | q >>= 4; |
MiniTLS | 0:35aa5be3b78d | 38 | } while (qq == 0); |
MiniTLS | 0:35aa5be3b78d | 39 | } |
MiniTLS | 0:35aa5be3b78d | 40 | return x; |
MiniTLS | 0:35aa5be3b78d | 41 | } |
MiniTLS | 0:35aa5be3b78d | 42 | |
MiniTLS | 0:35aa5be3b78d | 43 | |
MiniTLS | 0:35aa5be3b78d | 44 | /* $Source: /cvs/libtom/tomsfastmath/src/bit/fp_cnt_lsb.c,v $ */ |
MiniTLS | 0:35aa5be3b78d | 45 | /* $Revision: 1.1 $ */ |
MiniTLS | 0:35aa5be3b78d | 46 | /* $Date: 2006/12/31 21:25:53 $ */ |