EXUART_UINTP_TXD
EXUART_UINTP_TXD | EXUART_UINTP_MODEM);
if (ISSET(uintp, EXUART_UINTP_TXD)) {
bus_space_write_4(iot, ioh, EXUART_UINTP, EXUART_UINTP_TXD);