lib/hcrypto/libtommath/bn_mp_neg.c

   1 #include "tommath_private.h"
   2 #ifdef BN_MP_NEG_C
   3 /* LibTomMath, multiple-precision integer library -- Tom St Denis */
   4 /* SPDX-License-Identifier: Unlicense */
   5
   6 /* b = -a */
   7 mp_err mp_neg(const mp_int *a, mp_int *b)
   8 {
   9    mp_err err;
  10    if (a != b) {
  11       if ((err = mp_copy(a, b)) != MP_OKAY) {
  12          return err;
  13       }
  14    }
  15
  16    if (!MP_IS_ZERO(b)) {
  17       b->sign = (a->sign == MP_ZPOS) ? MP_NEG : MP_ZPOS;
  18    } else {
  19       b->sign = MP_ZPOS;
  20    }
  21
  22    return MP_OKAY;
  23 }
  24 #endif