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annotate bn_mp_reduce_setup.c @ 282:91fbc376f010 libtommath-orig libtommath-0.35

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Import of libtommath 0.35 From ltm-0.35.tar.bz2 SHA1 of 3f193dbae9351e92d02530994fa18236f7fde01c
author Matt Johnston <matt@ucc.asn.au>
date Wed, 08 Mar 2006 13:16:18 +0000
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children 97db060d0ef5
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1 #include <tommath.h>
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2 #ifdef BN_MP_REDUCE_SETUP_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 /* pre-calculate the value required for Barrett reduction
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19 * For a given modulus "b" it calulates the value required in "a"
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20 */
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21 int mp_reduce_setup (mp_int * a, mp_int * b)
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22 {
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23 int res;
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24
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25 if ((res = mp_2expt (a, b->used * 2 * DIGIT_BIT)) != MP_OKAY) {
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26 return res;
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27 }
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28 return mp_div (a, b, a, NULL);
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29 }
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30 #endif