Mercurial > dropbear

comparison libtommath/bn_mp_add.c @ 1692:1051e4eea25a

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Update LibTomMath to 1.2.0 (#84) * update C files * update other files * update headers * update makefiles * remove mp_set/get_double() * use ltm 1.2.0 API * update ltm_desc * use bundled tommath if system-tommath is too old * XMALLOC etc. were changed to MP_MALLOC etc.
author Steffen Jaeckel <s@jaeckel.eu>
date Tue, 26 May 2020 17:36:47 +0200
parents f52919ffd3b1
children
comparison
equal deleted inserted replaced
1691:2d3745d58843 1692:1051e4eea25a
1 #include "tommath_private.h" 1 #include "tommath_private.h"
2 #ifdef BN_MP_ADD_C 2 #ifdef BN_MP_ADD_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 * SPDX-License-Identifier: Unlicense
13 */
14 5
15 /* high level addition (handles signs) */ 6 /* high level addition (handles signs) */
16 int mp_add(const mp_int *a, const mp_int *b, mp_int *c) 7 mp_err mp_add(const mp_int *a, const mp_int *b, mp_int *c)
17 { 8 {
18 int sa, sb, res; 9 mp_sign sa, sb;
10 mp_err err;
19 11
20 /* get sign of both inputs */ 12 /* get sign of both inputs */
21 sa = a->sign; 13 sa = a->sign;
22 sb = b->sign; 14 sb = b->sign;
23 15
24 /* handle two cases, not four */ 16 /* handle two cases, not four */
25 if (sa == sb) { 17 if (sa == sb) {
26 /* both positive or both negative */ 18 /* both positive or both negative */
27 /* add their magnitudes, copy the sign */ 19 /* add their magnitudes, copy the sign */
28 c->sign = sa; 20 c->sign = sa;
29 res = s_mp_add(a, b, c); 21 err = s_mp_add(a, b, c);
30 } else { 22 } else {
31 /* one positive, the other negative */ 23 /* one positive, the other negative */
32 /* subtract the one with the greater magnitude from */ 24 /* subtract the one with the greater magnitude from */
33 /* the one of the lesser magnitude. The result gets */ 25 /* the one of the lesser magnitude. The result gets */
34 /* the sign of the one with the greater magnitude. */ 26 /* the sign of the one with the greater magnitude. */
35 if (mp_cmp_mag(a, b) == MP_LT) { 27 if (mp_cmp_mag(a, b) == MP_LT) {
36 c->sign = sb; 28 c->sign = sb;
37 res = s_mp_sub(b, a, c); 29 err = s_mp_sub(b, a, c);
38 } else { 30 } else {
39 c->sign = sa; 31 c->sign = sa;
40 res = s_mp_sub(a, b, c); 32 err = s_mp_sub(a, b, c);
41 } 33 }
42 } 34 }
43 return res; 35 return err;
44 } 36 }
45 37
46 #endif 38 #endif
47
48 /* ref: HEAD -> master, tag: v1.1.0 */
49 /* git commit: 08549ad6bc8b0cede0b357a9c341c5c6473a9c55 */
50 /* commit time: 2019-01-28 20:32:32 +0100 */