view libtommath/bn_mp_reduce_setup.c @ 1793:f90e681b8b8c

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author Matt Johnston <matt@ucc.asn.au>
date Fri, 29 Jan 2021 21:59:12 +0800
parents 1051e4eea25a
children
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#include "tommath_private.h"
#ifdef BN_MP_REDUCE_SETUP_C
/* LibTomMath, multiple-precision integer library -- Tom St Denis */
/* SPDX-License-Identifier: Unlicense */

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