arch.sm213.machine
Class AbstractSM213CPU

java.lang.Object
  java.util.Observable
      machine.AbstractCPU
          arch.sm213.machine.AbstractSM213CPU

Direct Known Subclasses:

CPU

public abstract class AbstractSM213CPU
extends AbstractCPU

Infrastructure for executing an SM213 CPU implementation.

Nested Class Summary

Nested classes/interfaces inherited from class machine.AbstractCPU

AbstractCPU.ImplementationException, AbstractCPU.InternalState, AbstractCPU.InvalidInstructionException, AbstractCPU.MachineHaltException

Field Summary

protected Register.Port	insOp0 Operand 0.
protected Register.Port	insOp1 Operand 1.
protected Register.Port	insOp2 Operand 2.
protected Register.Port	insOpCode Opcode.
protected Register.Port	insOpExt Extended operand (extra 4 bytes).
protected Register.Port	insOpImm Immediate-value operand.
protected Register.Port	instruction Value of current instruction (in its entirety).
protected Register.Port	pc Program counter (address of next instruction).
protected AbstractMainMemory.Port	physMem Physical memory (in case mem, is virtual memory)
protected RegisterSet	ps Internal machine registers.
protected Register.Port	ptbr

Fields inherited from class machine.AbstractCPU

is, mem, reg

Constructor Summary

AbstractSM213CPU(String name, AbstractMainMemory memory)
Create a new CPU.

Method Summary

protected void	cycle() Compute one cycle of the SM213 CPU
void	enableVirtualMemory() Enable Virtual Memory address translation.
protected abstract void	execute() Execute instruction currently loaded in processorState registers.
protected abstract void	fetch() Fetch next instruction from memory into CPU processorState registers.
void	setPC(int aPC) Set PC.
int	translateAddress(int va) Translate address from virtual to physical.

Methods inherited from class machine.AbstractCPU

getMainMemory, getName, getPC, getProcessorState, getRegisterFile, isInterrupt, newInstance, start, triggerInterrupt

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

ps

protected RegisterSet ps

Internal machine registers.

ptbr

protected Register.Port ptbr

pc

protected Register.Port pc

Program counter (address of next instruction).

instruction

protected Register.Port instruction

Value of current instruction (in its entirety).

insOpCode

protected Register.Port insOpCode

Opcode.

insOp0

protected Register.Port insOp0

Operand 0.

insOp1

protected Register.Port insOp1

Operand 1.

insOp2

protected Register.Port insOp2

Operand 2.

insOpImm

protected Register.Port insOpImm

Immediate-value operand.

insOpExt

protected Register.Port insOpExt

Extended operand (extra 4 bytes).

physMem

protected AbstractMainMemory.Port physMem

Physical memory (in case mem, is virtual memory)

Constructor Detail

AbstractSM213CPU

public AbstractSM213CPU(String name,
                        AbstractMainMemory memory)

Create a new CPU.

Parameters:

name - fully-qualified name of CPU implementation.

memory - main memory used by CPU.

Method Detail

enableVirtualMemory

public void enableVirtualMemory()

Enable Virtual Memory address translation.

translateAddress

public int translateAddress(int va)
                     throws AbstractMainMemory.InvalidAddressException

Translate address from virtual to physical. By default there is no translation. Subclasses extend to implement virtual memory.

Parameters:

va - virtual address

Returns:

physical address

Throws:

AbstractMainMemory.InvalidAddressException - if address is not valid

cycle

protected void cycle()
              throws AbstractCPU.InvalidInstructionException,
                     AbstractCPU.MachineHaltException,
                     AbstractMainMemory.InvalidAddressException

Compute one cycle of the SM213 CPU

Specified by:

cycle in class AbstractCPU

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.

setPC

public void setPC(int aPC)

Set PC.

Overrides:

setPC in class AbstractCPU

Parameters:

aPC - New memory address for PC.

fetch

protected abstract void fetch()
                       throws AbstractMainMemory.InvalidAddressException

Fetch next instruction from memory into CPU processorState registers.

Throws:

AbstractMainMemory.InvalidAddressException - Program counter stores an invalid memory address for fetching a new instruction.

execute

protected abstract void execute()
                         throws AbstractCPU.InvalidInstructionException,
                                AbstractCPU.MachineHaltException,
                                RegisterSet.InvalidRegisterNumberException,
                                AbstractMainMemory.InvalidAddressException

Execute instruction currently loaded in processorState registers.

Throws:

AbstractCPU.InvalidInstructionException - instruction is invalid.

AbstractCPU.MachineHaltException - instruction is the halt instruction.

RegisterSet.InvalidRegisterNumberException - instruction encodes an invalid register number.

AbstractMainMemory.InvalidAddressException - instruction encodes an invalid memory address.