machine
Class AbstractCPU

java.lang.Object
  java.util.Observable
      machine.AbstractCPU

Direct Known Subclasses:

AbstractSM213CPU

public abstract class AbstractCPU
extends Observable

Nested Class Summary

class	AbstractCPU.ImplementationException Exception indicating an internal error in CPU implementation.
static class	AbstractCPU.InternalState AbstractCPU internal state.
class	AbstractCPU.InvalidInstructionException Exception indicating that an invalid instruction was just detected by the CPU.
class	AbstractCPU.MachineHaltException Exception indicating that the CPU just retired a halt instruction.

Field Summary

AbstractCPU.InternalState	is Internal state not accessed by concerete sub-classes.
protected AbstractMainMemory.Port	mem Link to CPU's main memory.
protected RegisterSet.Ports	reg General purpose register file.

Constructor Summary

AbstractCPU(String aName, AbstractMainMemory aMem)
Create a new CPU.

Method Summary

protected abstract void	cycle() Compute one cycle of CPU.
AbstractMainMemory	getMainMemory() Get value of CPU's main memory.
String	getName() Get fully-qualified name of this implementation.
DataModel	getPC() Get the program-counter value.
Vector<RegisterSet>	getProcessorState() Get the CPU's processor state.
RegisterSet	getRegisterFile() Get the CPU's register file.
boolean	isInterrupt() Determing whether CPU has a pending interrupt.
static AbstractCPU	newInstance(AbstractCPU aCPU) Create a new instance of the same underlying type and with the same constructor parameters as existing cpu.
void	setPC(int aPC) Set program-counter value
void	start() Start processor execution.
void	triggerInterrupt() Trigger an interrupt on CPU.

Methods inherited from class java.util.Observable

addObserver, clearChanged, countObservers, deleteObserver, deleteObservers, hasChanged, notifyObservers, notifyObservers, setChanged

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

is

public final AbstractCPU.InternalState is

Internal state not accessed by concerete sub-classes.

reg

protected RegisterSet.Ports reg

General purpose register file.

mem

protected AbstractMainMemory.Port mem

Link to CPU's main memory.

Constructor Detail

AbstractCPU

public AbstractCPU(String aName,
                   AbstractMainMemory aMem)

Create a new CPU.

Parameters:

aName - fully-qualified name of CPU implementation.

aMem - main memory used by CPU.

Method Detail

newInstance

public static AbstractCPU newInstance(AbstractCPU aCPU)

Create a new instance of the same underlying type and with the same constructor parameters as existing cpu.

Parameters:

aCPU - CPU object who's class and value is used as the basis of the new CPU.

getMainMemory

public AbstractMainMemory getMainMemory()

Get value of CPU's main memory.

getRegisterFile

public RegisterSet getRegisterFile()

Get the CPU's register file.

getProcessorState

public Vector<RegisterSet> getProcessorState()

Get the CPU's processor state.

getName

public String getName()

Get fully-qualified name of this implementation.

getPC

public DataModel getPC()

Get the program-counter value.

setPC

public void setPC(int aPC)

Set program-counter value

cycle

protected abstract void cycle()
                       throws AbstractCPU.InvalidInstructionException,
                              AbstractCPU.MachineHaltException,
                              AbstractMainMemory.InvalidAddressException,
                              Register.TimingException,
                              AbstractCPU.ImplementationException

Compute one cycle of CPU.

Throws:

AbstractCPU.InvalidInstructionException - attempted to execute an invalid instruction.

AbstractCPU.MachineHaltException - halt instruction executed.

AbstractMainMemory.InvalidAddressException - attempted to execute an instruction that accesses an invalid memory address.

Register.TimingException - if instruction stalls on reading register input port.

AbstractCPU.ImplementationException - wrapper for all other exception for reporting to UI.

triggerInterrupt

public void triggerInterrupt()

Trigger an interrupt on CPU. If CPU is executing in start() it stops by returning from start().

isInterrupt

public boolean isInterrupt()

Determing whether CPU has a pending interrupt.

Returns:

true iff triggerInterrupt has been called, but start() has not yet stopped as a result of that interrupt.

start

public void start()
           throws AbstractCPU.InvalidInstructionException,
                  AbstractCPU.MachineHaltException,
                  AbstractMainMemory.InvalidAddressException,
                  Register.TimingException,
                  AbstractCPU.ImplementationException

Start processor execution. Continues executing until an exception is thrown or an interrupt is triggered. If start() returns without throwing an exception then an interrupt has occured.

Throws:

AbstractCPU.InvalidInstructionException - attempted to execute an invalid instruction.

AbstractCPU.MachineHaltException - halt instruction executed.

AbstractMainMemory.InvalidAddressException - attempted to execute an instruction that accesses an invalid memory address.

Register.TimingException - if instruction stalls on reading register input port.

AbstractCPU.ImplementationException - wrapper for all other exception for reporting to UI.