dropbear/libtommath/bn_mp_mod.c
Steffen Jaeckel b4bd23b4d2
Update LibTomMath to 1.2.0 (#84)
* update C files

* update other files

* update headers

* update makefiles

* remove mp_set/get_double()

* use ltm 1.2.0 API

* update ltm_desc

* use bundled tommath if system-tommath is too old

* XMALLOC etc. were changed to MP_MALLOC etc.
2020-05-26 23:36:47 +08:00

32 lines
657 B
C

#include "tommath_private.h"
#ifdef BN_MP_MOD_C
/* LibTomMath, multiple-precision integer library -- Tom St Denis */
/* SPDX-License-Identifier: Unlicense */
/* c = a mod b, 0 <= c < b if b > 0, b < c <= 0 if b < 0 */
mp_err mp_mod(const mp_int *a, const mp_int *b, mp_int *c)
{
mp_int t;
mp_err err;
if ((err = mp_init_size(&t, b->used)) != MP_OKAY) {
return err;
}
if ((err = mp_div(a, b, NULL, &t)) != MP_OKAY) {
goto LBL_ERR;
}
if (MP_IS_ZERO(&t) || (t.sign == b->sign)) {
err = MP_OKAY;
mp_exch(&t, c);
} else {
err = mp_add(b, &t, c);
}
LBL_ERR:
mp_clear(&t);
return err;
}
#endif