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move overrun detection and reset into the abstract superclass for ACIAs

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This commit is contained in:
Maik Merten 2014-07-19 17:10:57 +02:00
parent cf36f731da
commit 4a37dd7463
2 changed files with 16 additions and 26 deletions
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5
src/main/java/com/loomcom/symon/devices/Acia.java
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@ -108,11 +108,16 @@ public abstract class Acia extends Device {
public synchronized int rxRead() {
lastRxRead = System.nanoTime();
overrun = false;
rxFull = false;
return rxChar;
}
public synchronized void rxWrite(int data) {
if(rxFull) {
overrun = true;
}
rxFull = true;
if (receiveIrqEnabled) {

37
src/main/java/com/loomcom/symon/devices/Acia6850.java
View File

@ -42,8 +42,8 @@ public class Acia6850 extends Acia {
public static final int ACIA_SIZE = 2;
static final int STAT_REG = 0; // read-only
static final int CTRL_REG = 0; // write-only
static final int STAT_REG = 0; // read-only
static final int CTRL_REG = 0; // write-only
static final int RX_REG = 1; // read-only
static final int TX_REG = 1; // write-only
@ -57,7 +57,7 @@ public class Acia6850 extends Acia {
public Acia6850(int address) throws MemoryRangeException {
super(address, ACIA_SIZE, "ACIA6850");
setBaudRate(2400);
setBaudRate(2400);
}
@Override
@ -87,28 +87,13 @@ public class Acia6850 extends Acia {
}
}
@Override
public synchronized int rxRead() {
overrun = false;
return super.rxRead();
}
@Override
public synchronized void rxWrite(int data) {
if(rxFull) {
overrun = true;
}
super.rxWrite(data);
}
private void setCommandRegister(int data) {
commandRegister = data;
// Bits 0 & 1 control the master reset
if((commandRegister & 0x01) != 0 && (commandRegister & 0x02) != 0) {
reset();
}
// Bits 0 & 1 control the master reset
if((commandRegister & 0x01) != 0 && (commandRegister & 0x02) != 0) {
reset();
}
// Bit 7 controls receiver IRQ behavior
receiveIrqEnabled = (commandRegister & 0x80) != 0;
@ -131,16 +116,16 @@ public class Acia6850 extends Acia {
if (txEmpty && System.nanoTime() >= (lastTxWrite + baudRateDelay)) {
stat |= 0x02;
}
if (overrun) {
stat |= 0x20;
}
if (overrun) {
stat |= 0x20;
}
return stat;
}
private synchronized void reset() {
overrun = false;
overrun = false;
rxFull = false;
txEmpty = true;
}