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comparison libtommath/bn_mp_prime_is_divisible.c @ 284:eed26cff980b

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propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583) to branch 'au.asn.ucc.matt.dropbear' (head fff0894a0399405a9410ea1c6d118f342cf2aa64)
author Matt Johnston <matt@ucc.asn.au>
date Wed, 08 Mar 2006 13:23:49 +0000
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children 5ff8218bcee9
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283:bd240aa12ba7 284:eed26cff980b
1 #include <tommath.h>
2 #ifdef BN_MP_PRIME_IS_DIVISIBLE_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 if an integers is divisible by one
19 * of the first PRIME_SIZE primes or not
20 *
21 * sets result to 0 if not, 1 if yes
22 */
23 int mp_prime_is_divisible (mp_int * a, int *result)
24 {
25 int err, ix;
26 mp_digit res;
27
28 /* default to not */
29 *result = MP_NO;
30
31 for (ix = 0; ix < PRIME_SIZE; ix++) {
32 /* what is a mod LBL_prime_tab[ix] */
33 if ((err = mp_mod_d (a, ltm_prime_tab[ix], &res)) != MP_OKAY) {
34 return err;
35 }
36
37 /* is the residue zero? */
38 if (res == 0) {
39 *result = MP_YES;
40 return MP_OKAY;
41 }
42 }
43
44 return MP_OKAY;
45 }
46 #endif