libtommath/bn_mp_reduce_2k_setup_l.c
2019-04-07 17:26:31 +02:00

29 lines
575 B
C

#include "tommath_private.h"
#ifdef BN_MP_REDUCE_2K_SETUP_L_C
/* LibTomMath, multiple-precision integer library -- Tom St Denis */
/* SPDX-License-Identifier: Unlicense */
/* determines the setup value */
int mp_reduce_2k_setup_l(const mp_int *a, mp_int *d)
{
int res;
mp_int tmp;
if ((res = mp_init(&tmp)) != MP_OKAY) {
return res;
}
if ((res = mp_2expt(&tmp, mp_count_bits(a))) != MP_OKAY) {
goto LBL_ERR;
}
if ((res = s_mp_sub(&tmp, a, d)) != MP_OKAY) {
goto LBL_ERR;
}
LBL_ERR:
mp_clear(&tmp);
return res;
}
#endif