Intel 386 User Manual page 329

Intel386™ EX EMBEDDED MICROPROCESSOR USER'S MANUAL
if ((msr0 & 0x04) && (msr0 & 0x40)) {
/* ring indicator */
}
if ((msr0 & 0x02) && (msr0 & 0x20)) {
/* data set ready bit has been set */
}
if ((msr0 & 0x01) && (msr0&0x10)) {
/* clear to send signal has been set */
}
break;
case 1:
Service_TBE(); /* Routine for Interrupt driven Serial Writes */
break;
case 2:
/* RBF signal */
Service_RBF(); /* Routine specific to RBF generated interrupts */
break;
case 3:
/* receive line status signal */
lsr0 = _GetEXRegByte(LSR0);
if (lsr0 & 0x10) {
/* break interrupt */
}
if (lsr0 & 0x08) {
/* framing error */
}
if (lsr0 & 0x04) {
/* parity error */
}
if (lsr0 & 0x02) {
/* overrun error */
}
break;
} /* End of switch */
NonSpecificEOI();
}/* Serial0_ISR */
11-42
// Send End-Of-Interrupt Signal to Master