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comparison libtommath/bn_mp_reduce_is_2k.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
comparison
equal deleted inserted replaced
1562:768ebf737aa0 1739:13d834efc376
1 #include <tommath_private.h> 1 #include "tommath_private.h"
2 #ifdef BN_MP_REDUCE_IS_2K_C 2 #ifdef BN_MP_REDUCE_IS_2K_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 /* determines if mp_reduce_2k can be used */ 6 /* determines if mp_reduce_2k can be used */
19 int mp_reduce_is_2k(mp_int *a) 7 mp_bool mp_reduce_is_2k(const mp_int *a)
20 { 8 {
21 int ix, iy, iw; 9 int ix, iy, iw;
22 mp_digit iz; 10 mp_digit iz;
23 11
24 if (a->used == 0) { 12 if (a->used == 0) {
25 return MP_NO; 13 return MP_NO;
26 } else if (a->used == 1) { 14 } else if (a->used == 1) {
27 return MP_YES; 15 return MP_YES;
28 } else if (a->used > 1) { 16 } else if (a->used > 1) {
29 iy = mp_count_bits(a); 17 iy = mp_count_bits(a);
30 iz = 1; 18 iz = 1;
31 iw = 1; 19 iw = 1;
32 20
33 /* Test every bit from the second digit up, must be 1 */ 21 /* Test every bit from the second digit up, must be 1 */
34 for (ix = DIGIT_BIT; ix < iy; ix++) { 22 for (ix = MP_DIGIT_BIT; ix < iy; ix++) {
35 if ((a->dp[iw] & iz) == 0) { 23 if ((a->dp[iw] & iz) == 0u) {
36 return MP_NO; 24 return MP_NO;
37 } 25 }
38 iz <<= 1; 26 iz <<= 1;
39 if (iz > (mp_digit)MP_MASK) { 27 if (iz > MP_DIGIT_MAX) {
40 ++iw; 28 ++iw;
41 iz = 1; 29 iz = 1;
42 } 30 }
43 } 31 }
32 return MP_YES;
33 } else {
34 return MP_YES;
44 } 35 }
45 return MP_YES;
46 } 36 }
47 37
48 #endif 38 #endif
49
50 /* ref: $Format:%D$ */
51 /* git commit: $Format:%H$ */
52 /* commit time: $Format:%ai$ */