view libtommath/bn_mp_reduce_setup.c @ 1671:5c8913b7464c

Mention Ed25519 in dropbearkey man (#94)
author Vladislav Grishenko <themiron@users.noreply.github.com>
date Mon, 25 May 2020 18:28:27 +0500
parents f52919ffd3b1
children 1051e4eea25a
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#include "tommath_private.h"
#ifdef BN_MP_REDUCE_SETUP_C
/* 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.
 *
 * SPDX-License-Identifier: Unlicense
 */

/* 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, const 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);
}
#endif

/* ref:         HEAD -> master, tag: v1.1.0 */
/* git commit:  08549ad6bc8b0cede0b357a9c341c5c6473a9c55 */
/* commit time: 2019-01-28 20:32:32 +0100 */