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comparison bn_mp_reduce_2k_setup_l.c @ 190:d8254fc979e9 libtommath-orig LTM_0.35

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Initial import of libtommath 0.35
author Matt Johnston <matt@ucc.asn.au>
date Fri, 06 May 2005 08:59:30 +0000
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children 97db060d0ef5
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142:d29b64170cf0 190:d8254fc979e9
1 #include <tommath.h>
2 #ifdef BN_MP_REDUCE_2K_SETUP_L_C
3 /* LibTomMath, multiple-precision integer library -- Tom St Denis
4 *
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 * The library is free for all purposes without any express
13 * guarantee it works.
14 *
15 * Tom St Denis, [email protected], http://math.libtomcrypt.org
16 */
17
18 /* determines the setup value */
19 int mp_reduce_2k_setup_l(mp_int *a, mp_int *d)
20 {
21 int res;
22 mp_int tmp;
23
24 if ((res = mp_init(&tmp)) != MP_OKAY) {
25 return res;
26 }
27
28 if ((res = mp_2expt(&tmp, mp_count_bits(a))) != MP_OKAY) {
29 goto ERR;
30 }
31
32 if ((res = s_mp_sub(&tmp, a, d)) != MP_OKAY) {
33 goto ERR;
34 }
35
36 ERR:
37 mp_clear(&tmp);
38 return res;
39 }
40 #endif