Mercurial > dropbear
comparison libtommath/bn_mp_2expt.c @ 1655:f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
* make key-generation compliant to FIPS 186.4
* fix includes in tommath_class.h
* update fuzzcorpus instead of error-out
* fixup fuzzing make-targets
* update Makefile.in
* apply necessary patches to ltm sources
* clean-up not required ltm files
* update to vanilla ltm 1.1.0
this already only contains the required files
* remove set/get double
author | Steffen Jaeckel <s_jaeckel@gmx.de> |
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date | Mon, 16 Sep 2019 15:50:38 +0200 |
parents | 8bba51a55704 |
children | 1051e4eea25a |
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1654:cc0fc5131c5c | 1655:f52919ffd3b1 |
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1 #include <tommath_private.h> | 1 #include "tommath_private.h" |
2 #ifdef BN_MP_2EXPT_C | 2 #ifdef BN_MP_2EXPT_C |
3 /* LibTomMath, multiple-precision integer library -- Tom St Denis | 3 /* LibTomMath, multiple-precision integer library -- Tom St Denis |
4 * | 4 * |
5 * LibTomMath is a library that provides multiple-precision | 5 * LibTomMath is a library that provides multiple-precision |
6 * integer arithmetic as well as number theoretic functionality. | 6 * integer arithmetic as well as number theoretic functionality. |
7 * | 7 * |
8 * The library was designed directly after the MPI library by | 8 * The library was designed directly after the MPI library by |
9 * Michael Fromberger but has been written from scratch with | 9 * Michael Fromberger but has been written from scratch with |
10 * additional optimizations in place. | 10 * additional optimizations in place. |
11 * | 11 * |
12 * The library is free for all purposes without any express | 12 * SPDX-License-Identifier: Unlicense |
13 * guarantee it works. | |
14 * | |
15 * Tom St Denis, [email protected], http://libtom.org | |
16 */ | 13 */ |
17 | 14 |
18 /* computes a = 2**b | 15 /* computes a = 2**b |
19 * | 16 * |
20 * Simple algorithm which zeroes the int, grows it then just sets one bit | 17 * Simple algorithm which zeroes the int, grows it then just sets one bit |
21 * as required. | 18 * as required. |
22 */ | 19 */ |
23 int | 20 int mp_2expt(mp_int *a, int b) |
24 mp_2expt (mp_int * a, int b) | |
25 { | 21 { |
26 int res; | 22 int res; |
27 | 23 |
28 /* zero a as per default */ | 24 /* zero a as per default */ |
29 mp_zero (a); | 25 mp_zero(a); |
30 | 26 |
31 /* grow a to accomodate the single bit */ | 27 /* grow a to accomodate the single bit */ |
32 if ((res = mp_grow (a, (b / DIGIT_BIT) + 1)) != MP_OKAY) { | 28 if ((res = mp_grow(a, (b / DIGIT_BIT) + 1)) != MP_OKAY) { |
33 return res; | 29 return res; |
34 } | 30 } |
35 | 31 |
36 /* set the used count of where the bit will go */ | 32 /* set the used count of where the bit will go */ |
37 a->used = (b / DIGIT_BIT) + 1; | 33 a->used = (b / DIGIT_BIT) + 1; |
38 | 34 |
39 /* put the single bit in its place */ | 35 /* put the single bit in its place */ |
40 a->dp[b / DIGIT_BIT] = ((mp_digit)1) << (b % DIGIT_BIT); | 36 a->dp[b / DIGIT_BIT] = (mp_digit)1 << (mp_digit)(b % DIGIT_BIT); |
41 | 37 |
42 return MP_OKAY; | 38 return MP_OKAY; |
43 } | 39 } |
44 #endif | 40 #endif |
45 | 41 |
46 /* ref: $Format:%D$ */ | 42 /* ref: HEAD -> master, tag: v1.1.0 */ |
47 /* git commit: $Format:%H$ */ | 43 /* git commit: 08549ad6bc8b0cede0b357a9c341c5c6473a9c55 */ |
48 /* commit time: $Format:%ai$ */ | 44 /* commit time: 2019-01-28 20:32:32 +0100 */ |