Mercurial > dropbear

annotate libtommath/bn_mp_prime_is_divisible.c @ 310:4b4478d0d2b9 ucc-axis-hack

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add a comment on usage
author Matt Johnston <matt@ucc.asn.au>
date Sun, 26 Mar 2006 08:28:16 +0000
parents eed26cff980b
children 5ff8218bcee9
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284
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1 #include <tommath.h>
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2 #ifdef BN_MP_PRIME_IS_DIVISIBLE_C
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3 /* LibTomMath, multiple-precision integer library -- Tom St Denis
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4 *
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5 * LibTomMath is a library that provides multiple-precision
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6 * integer arithmetic as well as number theoretic functionality.
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7 *
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8 * The library was designed directly after the MPI library by
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9 * Michael Fromberger but has been written from scratch with
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10 * additional optimizations in place.
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11 *
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12 * The library is free for all purposes without any express
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13 * guarantee it works.
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14 *
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15 * Tom St Denis, [email protected], http://math.libtomcrypt.org
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16 */
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17
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18 /* determines if an integers is divisible by one
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19 * of the first PRIME_SIZE primes or not
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20 *
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21 * sets result to 0 if not, 1 if yes
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22 */
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23 int mp_prime_is_divisible (mp_int * a, int *result)
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24 {
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25 int err, ix;
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26 mp_digit res;
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27
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28 /* default to not */
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29 *result = MP_NO;
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30
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31 for (ix = 0; ix < PRIME_SIZE; ix++) {
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32 /* what is a mod LBL_prime_tab[ix] */
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33 if ((err = mp_mod_d (a, ltm_prime_tab[ix], &res)) != MP_OKAY) {
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34 return err;
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35 }
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36
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37 /* is the residue zero? */
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38 if (res == 0) {
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39 *result = MP_YES;
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40 return MP_OKAY;
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41 }
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42 }
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43
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44 return MP_OKAY;
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45 }
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46 #endif