EXUART_UINTP_RXD
EXUART_UINTP_RXD | EXUART_UINTP_ERROR |
if (ISSET(uintp, EXUART_UINTP_RXD)) {
bus_space_write_4(iot, ioh, EXUART_UINTP, EXUART_UINTP_RXD);