view bn_mp_reduce_setup.c @ 19:e1037a1e12e7 libtommath-orig

0.30 release of LibTomMath
author Matt Johnston <matt@ucc.asn.au>
date Tue, 15 Jun 2004 14:42:57 +0000
parents 86e0b50a9b58
children d29b64170cf0
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/* 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, [email protected], http://math.libtomcrypt.org
 */
#include <tommath.h>

/* pre-calculate the value required for Barrett reduction
 * For a given modulus "b" it calulates the value required in "a"
 */
int
mp_reduce_setup (mp_int * a, mp_int * b)
{
  int     res;
  
  if ((res = mp_2expt (a, b->used * 2 * DIGIT_BIT)) != MP_OKAY) {
    return res;
  }
  return mp_div (a, b, a, NULL);
}