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comparison bn_mp_mod.c @ 2:86e0b50a9b58 libtommath-orig ltm-0.30-orig

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ltm 0.30 orig import
author Matt Johnston <matt@ucc.asn.au>
date Mon, 31 May 2004 18:25:22 +0000
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children d29b64170cf0
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-1:000000000000 2:86e0b50a9b58
1 /* LibTomMath, multiple-precision integer library -- Tom St Denis
2 *
3 * LibTomMath is a library that provides multiple-precision
4 * integer arithmetic as well as number theoretic functionality.
5 *
6 * The library was designed directly after the MPI library by
7 * Michael Fromberger but has been written from scratch with
8 * additional optimizations in place.
9 *
10 * The library is free for all purposes without any express
11 * guarantee it works.
12 *
13 * Tom St Denis, [email protected], http://math.libtomcrypt.org
14 */
15 #include <tommath.h>
16
17 /* c = a mod b, 0 <= c < b */
18 int
19 mp_mod (mp_int * a, mp_int * b, mp_int * c)
20 {
21 mp_int t;
22 int res;
23
24 if ((res = mp_init (&t)) != MP_OKAY) {
25 return res;
26 }
27
28 if ((res = mp_div (a, b, NULL, &t)) != MP_OKAY) {
29 mp_clear (&t);
30 return res;
31 }
32
33 if (t.sign != b->sign) {
34 res = mp_add (b, &t, c);
35 } else {
36 res = MP_OKAY;
37 mp_exch (&t, c);
38 }
39
40 mp_clear (&t);
41 return res;
42 }