multiply_digit
if ((res = multiply_digit(&t1, q.dp[i - t - 1], &t1)) != MP_OKAY) {
if ((res = multiply_digit(&y, q.dp[i - t - 1], &t1)) != MP_OKAY) {
if ((res = multiply_digit(&w2, 3, &w2)) != MP_OKAY) {
if ((res = multiply_digit(&w2, 3, &w2)) != MP_OKAY) {
if ((res = multiply_digit(&q, d, &q)) != MP_OKAY) {
if ((err = multiply_digit(a, radix, a)) != MP_OKAY) {