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comparison libtommath/bn_mp_lcm.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_LCM_C 2 #ifdef BN_MP_LCM_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 least common multiple as |a*b|/(a, b) */ 15 /* computes least common multiple as |a*b|/(a, b) */
19 int mp_lcm (mp_int * a, mp_int * b, mp_int * c) 16 int mp_lcm(const mp_int *a, const mp_int *b, mp_int *c)
20 { 17 {
21 int res; 18 int res;
22 mp_int t1, t2; 19 mp_int t1, t2;
23 20
24 21
25 if ((res = mp_init_multi (&t1, &t2, NULL)) != MP_OKAY) { 22 if ((res = mp_init_multi(&t1, &t2, NULL)) != MP_OKAY) {
26 return res; 23 return res;
27 } 24 }
28 25
29 /* t1 = get the GCD of the two inputs */ 26 /* t1 = get the GCD of the two inputs */
30 if ((res = mp_gcd (a, b, &t1)) != MP_OKAY) { 27 if ((res = mp_gcd(a, b, &t1)) != MP_OKAY) {
31 goto LBL_T; 28 goto LBL_T;
32 } 29 }
33 30
34 /* divide the smallest by the GCD */ 31 /* divide the smallest by the GCD */
35 if (mp_cmp_mag(a, b) == MP_LT) { 32 if (mp_cmp_mag(a, b) == MP_LT) {
36 /* store quotient in t2 such that t2 * b is the LCM */ 33 /* store quotient in t2 such that t2 * b is the LCM */
37 if ((res = mp_div(a, &t1, &t2, NULL)) != MP_OKAY) { 34 if ((res = mp_div(a, &t1, &t2, NULL)) != MP_OKAY) {
38 goto LBL_T; 35 goto LBL_T;
39 } 36 }
40 res = mp_mul(b, &t2, c); 37 res = mp_mul(b, &t2, c);
41 } else { 38 } else {
42 /* store quotient in t2 such that t2 * a is the LCM */ 39 /* store quotient in t2 such that t2 * a is the LCM */
43 if ((res = mp_div(b, &t1, &t2, NULL)) != MP_OKAY) { 40 if ((res = mp_div(b, &t1, &t2, NULL)) != MP_OKAY) {
44 goto LBL_T; 41 goto LBL_T;
45 } 42 }
46 res = mp_mul(a, &t2, c); 43 res = mp_mul(a, &t2, c);
47 } 44 }
48 45
49 /* fix the sign to positive */ 46 /* fix the sign to positive */
50 c->sign = MP_ZPOS; 47 c->sign = MP_ZPOS;
51 48
52 LBL_T: 49 LBL_T:
53 mp_clear_multi (&t1, &t2, NULL); 50 mp_clear_multi(&t1, &t2, NULL);
54 return res; 51 return res;
55 } 52 }
56 #endif 53 #endif
57 54
58 /* ref: $Format:%D$ */ 55 /* ref: HEAD -> master, tag: v1.1.0 */
59 /* git commit: $Format:%H$ */ 56 /* git commit: 08549ad6bc8b0cede0b357a9c341c5c6473a9c55 */
60 /* commit time: $Format:%ai$ */ 57 /* commit time: 2019-01-28 20:32:32 +0100 */