summaryrefslogtreecommitdiffstats
path: root/libtommath/bn_mp_reduce_2k_setup_l.c
blob: 9ab778583b3b43a195373e805ac33806ebcfd01c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
#include <tommath.h>
#ifdef BN_MP_REDUCE_2K_SETUP_L_C
/* LibTomMath, multiple-precision integer library -- Tom St Denis
 *
 * LibTomMath is a library that provides multiple-precision
 * integer arithmetic as well as number theoretic functionality.
 *
 * The library was designed directly after the MPI library by
 * Michael Fromberger but has been written from scratch with
 * additional optimizations in place.
 *
 * The library is free for all purposes without any express
 * guarantee it works.
 *
 * Tom St Denis, tomstdenis@gmail.com, http://libtom.org
 */

/* determines the setup value */
int mp_reduce_2k_setup_l(mp_int * a, mp_int * d)
{
	int res;
	mp_int tmp;

	if ((res = mp_init(&tmp)) != MP_OKAY) {
		return res;
	}

	if ((res = mp_2expt(&tmp, mp_count_bits(a))) != MP_OKAY) {
		goto ERR;
	}

	if ((res = s_mp_sub(&tmp, a, d)) != MP_OKAY) {
		goto ERR;
	}

ERR:
	mp_clear(&tmp);
	return res;
}
#endif

/* $Source: /cvs/libtom/libtommath/bn_mp_reduce_2k_setup_l.c,v $ */
/* $Revision: 1.4 $ */
/* $Date: 2006/12/28 01:25:13 $ */