libtommath/bn_mp_reduce_setup.c
2019-04-07 17:26:31 +02:00

19 lines
494 B
C

#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"
*/
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