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comparison bn_mp_submod.c @ 1:22d5cf7d4b1a libtommath

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Renaming branch
author Matt Johnston <matt@ucc.asn.au>
date Mon, 31 May 2004 18:23:46 +0000
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-1:000000000000 1:22d5cf7d4b1a
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 /* d = a - b (mod c) */
18 int
19 mp_submod (mp_int * a, mp_int * b, mp_int * c, mp_int * d)
20 {
21 int res;
22 mp_int t;
23
24
25 if ((res = mp_init (&t)) != MP_OKAY) {
26 return res;
27 }
28
29 if ((res = mp_sub (a, b, &t)) != MP_OKAY) {
30 mp_clear (&t);
31 return res;
32 }
33 res = mp_mod (&t, c, d);
34 mp_clear (&t);
35 return res;
36 }