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comparison libtommath/bn_mp_mul_d.c @ 1692:1051e4eea25a

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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
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1691:2d3745d58843 1692:1051e4eea25a
1 #include "tommath_private.h" 1 #include "tommath_private.h"
2 #ifdef BN_MP_MUL_D_C 2 #ifdef BN_MP_MUL_D_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 /* multiply by a digit */ 6 /* multiply by a digit */
16 int mp_mul_d(const mp_int *a, mp_digit b, mp_int *c) 7 mp_err mp_mul_d(const mp_int *a, mp_digit b, mp_int *c)
17 { 8 {
18 mp_digit u, *tmpa, *tmpc; 9 mp_digit u, *tmpa, *tmpc;
19 mp_word r; 10 mp_word r;
20 int ix, res, olduse; 11 mp_err err;
12 int ix, olduse;
21 13
22 /* make sure c is big enough to hold a*b */ 14 /* make sure c is big enough to hold a*b */
23 if (c->alloc < (a->used + 1)) { 15 if (c->alloc < (a->used + 1)) {
24 if ((res = mp_grow(c, a->used + 1)) != MP_OKAY) { 16 if ((err = mp_grow(c, a->used + 1)) != MP_OKAY) {
25 return res; 17 return err;
26 } 18 }
27 } 19 }
28 20
29 /* get the original destinations used count */ 21 /* get the original destinations used count */
30 olduse = c->used; 22 olduse = c->used;
48 40
49 /* mask off higher bits to get a single digit */ 41 /* mask off higher bits to get a single digit */
50 *tmpc++ = (mp_digit)(r & (mp_word)MP_MASK); 42 *tmpc++ = (mp_digit)(r & (mp_word)MP_MASK);
51 43
52 /* send carry into next iteration */ 44 /* send carry into next iteration */
53 u = (mp_digit)(r >> (mp_word)DIGIT_BIT); 45 u = (mp_digit)(r >> (mp_word)MP_DIGIT_BIT);
54 } 46 }
55 47
56 /* store final carry [if any] and increment ix offset */ 48 /* store final carry [if any] and increment ix offset */
57 *tmpc++ = u; 49 *tmpc++ = u;
58 ++ix; 50 ++ix;
59 51
60 /* now zero digits above the top */ 52 /* now zero digits above the top */
61 while (ix++ < olduse) { 53 MP_ZERO_DIGITS(tmpc, olduse - ix);
62 *tmpc++ = 0;
63 }
64 54
65 /* set used count */ 55 /* set used count */
66 c->used = a->used + 1; 56 c->used = a->used + 1;
67 mp_clamp(c); 57 mp_clamp(c);
68 58
69 return MP_OKAY; 59 return MP_OKAY;
70 } 60 }
71 #endif 61 #endif
72
73 /* ref: HEAD -> master, tag: v1.1.0 */
74 /* git commit: 08549ad6bc8b0cede0b357a9c341c5c6473a9c55 */
75 /* commit time: 2019-01-28 20:32:32 +0100 */