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comparison libtommath/bn_mp_2expt.c @ 1655:f52919ffd3b1

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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>
date Mon, 16 Sep 2019 15:50:38 +0200
parents 8bba51a55704
children 1051e4eea25a
comparison
equal deleted inserted replaced
1654:cc0fc5131c5c 1655:f52919ffd3b1
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 */