Fixed 6850 behaviour

+ Fixed interrupt bit reset behaviour

src/main/java/com/loomcom/symon/devices/Acia6850.java

@@ -56,6 +56,9 @@ public class Acia6850 extends Acia {
     public int read(int address, boolean cpuAccess) throws MemoryAccessException {
         switch (address) {
             case RX_REG:
+                if (cpuAccess) {
+                    interrupt = false;
+                }
                 return rxRead(cpuAccess);
             case STAT_REG:
                 return statusReg(cpuAccess);
@@ -69,6 +72,9 @@ public class Acia6850 extends Acia {
     public void write(int address, int data) throws MemoryAccessException {
         switch (address) {
             case TX_REG:
+                if (cpuAccess) {
+                    interrupt = false;
+                }
                 txWrite(data);
                 break;
             case CTRL_REG:
@@ -113,10 +119,6 @@ public class Acia6850 extends Acia {
             stat |= 0x80;
         }
 
-        if (cpuAccess) {
-            interrupt = false;
-        }
-
         return stat;
     }