STAT_RX_RDY
if (status & STAT_RX_RDY(port)) {
status &= ~STAT_RX_RDY(port);
if (status & STAT_RX_RDY(port))
} while (status & (STAT_RX_RDY(port) | STAT_BRK_DET));
if (st & (STAT_RX_RDY(port) | STAT_OVR_ERR | STAT_FRM_ERR |
if (st & (STAT_RX_RDY(port) | STAT_OVR_ERR | STAT_FRM_ERR |
port->read_status_mask = STAT_RX_RDY(port) | STAT_OVR_ERR |
port->ignore_status_mask |= STAT_RX_RDY(port) | STAT_BRK_ERR;
if (!(st & STAT_RX_RDY(port)))