s_mp_mul_d_add_offset
s_mp_mul_d_add_offset(p, v, x, ix); /* x += p * v * (RADIX ** ix) */
s_mp_mul_d_add_offset(&mmm->N, m_i, T, i);
s_mp_mul_d_add_offset(&mmm->N, m_i, c, 0);
s_mp_mul_d_add_offset(&mmm->N, m_i, c, ib);
s_mp_mul_d_add_offset(&mmm->N, m_i, c, ib);