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comparison libtommath/bn_mp_2expt.c @ 1739:13d834efc376 fuzz

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merge from main
author Matt Johnston <matt@ucc.asn.au>
date Thu, 15 Oct 2020 19:55:15 +0800
parents 1051e4eea25a
children
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1562:768ebf737aa0 1739:13d834efc376
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 /* SPDX-License-Identifier: Unlicense */
5 * LibTomMath is a library that provides multiple-precision
6 * integer arithmetic as well as number theoretic functionality.
7 *
8 * The library was designed directly after the MPI library by
9 * Michael Fromberger but has been written from scratch with
10 * additional optimizations in place.
11 *
12 * The library is free for all purposes without any express
13 * guarantee it works.
14 *
15 * Tom St Denis, [email protected], http://libtom.org
16 */
17 5
18 /* computes a = 2**b 6 /* computes a = 2**b
19 * 7 *
20 * Simple algorithm which zeroes the int, grows it then just sets one bit 8 * Simple algorithm which zeroes the int, grows it then just sets one bit
21 * as required. 9 * as required.
22 */ 10 */
23 int 11 mp_err mp_2expt(mp_int *a, int b)
24 mp_2expt (mp_int * a, int b)
25 { 12 {
26 int res; 13 mp_err err;
27 14
28 /* zero a as per default */ 15 /* zero a as per default */
29 mp_zero (a); 16 mp_zero(a);
30 17
31 /* grow a to accomodate the single bit */ 18 /* grow a to accomodate the single bit */
32 if ((res = mp_grow (a, (b / DIGIT_BIT) + 1)) != MP_OKAY) { 19 if ((err = mp_grow(a, (b / MP_DIGIT_BIT) + 1)) != MP_OKAY) {
33 return res; 20 return err;
34 } 21 }
35 22
36 /* set the used count of where the bit will go */ 23 /* set the used count of where the bit will go */
37 a->used = (b / DIGIT_BIT) + 1; 24 a->used = (b / MP_DIGIT_BIT) + 1;
38 25
39 /* put the single bit in its place */ 26 /* put the single bit in its place */
40 a->dp[b / DIGIT_BIT] = ((mp_digit)1) << (b % DIGIT_BIT); 27 a->dp[b / MP_DIGIT_BIT] = (mp_digit)1 << (mp_digit)(b % MP_DIGIT_BIT);
41 28
42 return MP_OKAY; 29 return MP_OKAY;
43 } 30 }
44 #endif 31 #endif
45
46 /* ref: $Format:%D$ */
47 /* git commit: $Format:%H$ */
48 /* commit time: $Format:%ai$ */