BN_set_negative
BN_set_negative(ret, 1);
BN_set_negative(ret, 1);
BN_set_negative(D, sign == -1);
BN_set_negative(b, 0);
BN_set_negative(b, 0);
BN_set_negative(a, 1);
BN_set_negative(&r->X, 0);
BN_set_negative(&r->Y, 0);
BN_set_negative(&point->X, 0);
BN_set_negative(&point->Y, 0);
BN_set_negative(&point->Z, 0);
BN_set_negative(x, 0);
BN_set_negative(y, 0);
BN_set_negative(&group->field, 0);
void BN_set_negative(BIGNUM *b, int n);
BN_set_negative(n->number, !BN_is_negative(n->number));
BN_set_negative(v, 0);