arch.sm213.machine.student
Class CPU

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

Direct Known Subclasses:

VirtualMemoryCPU

public class CPU
extends AbstractSM213CPU

The Simple Machine CPU. Simulate the execution of a single cycle of the Simple Machine SM213 CPU.

Nested Class Summary

Nested classes/interfaces inherited from class machine.AbstractCPU

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

Field Summary

Fields inherited from class arch.sm213.machine.AbstractSM213CPU

insOp0, insOp1, insOp2, insOpCode, insOpExt, insOpImm, instruction, pc, physMem, ps, ptbr

Fields inherited from class machine.AbstractCPU

is, mem, reg

Constructor Summary

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

Method Summary

protected void	execute() Execution Stage of CPU Cycle.
protected void	fetch() Fetch Stage of CPU Cycle.

Methods inherited from class arch.sm213.machine.AbstractSM213CPU

cycle, enableVirtualMemory, setPC, translateAddress

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

Constructor Detail

CPU

public CPU(String name,
           AbstractMainMemory memory)

Create a new CPU.

Parameters:

name - fully-qualified name of CPU implementation.

memory - main memory used by CPU.

Method Detail

fetch

protected void fetch()
              throws AbstractMainMemory.InvalidAddressException

Fetch Stage of CPU Cycle. Fetch instruction at address stored in "pc" register from memory into instruction register and set "pc" to point to the next instruction to execute. Input register: pc. Output registers: pc, instruction, insOpCode, insOp0, insOp1, insOp2, insOpImm, insOpExt

Specified by:

fetch in class AbstractSM213CPU

Throws:

MainMemory.InvalidAddressException - when program counter contains an invalid memory address.

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

See Also:

for pc, instruction, insOpCode, insOp0, insOp1, insOp2, insOpImm, insOpExt

execute

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

Execution Stage of CPU Cycle. Execute instruction that was fetched by Fetch stage. Input state: pc, instruction, insOpCode, insOp0, insOp1, insOp2, insOpImm, insOpExt, reg, mem Ouput state: pc, reg, mem

Specified by:

execute in class AbstractSM213CPU

Throws:

InvalidInstructionException - when instruction format is invalid.

MachineHaltException - when instruction is the HALT instruction.

RegisterSet.InvalidRegisterNumberException - when instruction references an invalid register (i.e, not 0-7).

MainMemory.InvalidAddressException - when instruction references an invalid memory address.

AbstractCPU.InvalidInstructionException - instruction is invalid.

AbstractCPU.MachineHaltException - instruction is the halt instruction.

AbstractMainMemory.InvalidAddressException - instruction encodes an invalid memory address.

See Also:

for pc, instruction, insOpCode, insOp0, insOp1, insOp2, insOpImm, insOpExt, for mem, for reg