edu.jmu.decaf

Class ILOCInterpreter

java.lang.Object

edu.jmu.decaf.ILOCInterpreter

All Implemented Interfaces:

ILOCProcessor

public class ILOCInterpreter
extends Object
implements ILOCProcessor

Simulates a simple architecture that can directly execute ILOC programs. Features:

• 32-bit word
• Unlimited 32-bit integer virtual registers
• Four special-purpose 32-bit integer registers:
  • IP - instruction pointer
  • SP - stack pointer
  • BP - base pointer
  • RET - function return value
• 64KB stack, heap, and data region
• Fixed-size, read-only code region indexed by instruction

Memory layout diagram:

 ---------------  2^16-1
 |    Stack    |
 |      |      |
 |      v      |
 |             |
 |             |
 \/\/\/\/\/\/\/\
 |             |
 |      ^      |
 |      |      |
 |     Heap    |
 ---------------
 |     Data    |
 ---------------  0

 ---------------
 |     Code    |
 ---------------
 

The IP register does not contain a valid memory address, but rather it points to the index of the next ILOCInstruction in the currently-executing ILOCFunction. The heap region is currently unused.

Constructor Summary

Constructors

Constructor and Description
ILOCInterpreter()
ILOCInterpreter(boolean trace)

Method Summary

Modifier and Type	Method and Description
void	assertAllRegOperands(ILOCInstruction insn, int regs)
void	assertIsValid(ILOCInstruction insn)
void	assertNumOperands(ILOCInstruction insn, int ops)
void	assertOperandIsRegister(ILOCInstruction insn, ILOCOperand op)
void	assertOperandType(ILOCInstruction insn, ILOCOperand op, ILOCOperand.Type type)
void	checkStack()
void	dumpSystemState()
int	findJumpTarget(ILOCOperand targ)
boolean	getBool(ILOCOperand src)
int	getInt(ILOCOperand src)
int	getReturnValue()
boolean	handle(ILOCInstruction insn)
int	loadInt(int address)
int	pop()
void	process(ILOCProgram program) Perform analysis and/or modification on the given ILOC program
void	push(int value)
void	setBool(ILOCOperand dst, boolean value)
void	setBool(ILOCOperand dst, int value)
void	setInt(ILOCOperand dst, int value)
void	storeInt(int address, int value)

Methods inherited from class java.lang.Object

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

Constructor Detail

ILOCInterpreter

public ILOCInterpreter()

ILOCInterpreter

public ILOCInterpreter(boolean trace)

Method Detail

process

public void process(ILOCProgram program)

Description copied from interface: ILOCProcessor

Perform analysis and/or modification on the given ILOC program

Specified by:

process in interface ILOCProcessor

Parameters:

program - ILOCProgram to process

assertNumOperands

public void assertNumOperands(ILOCInstruction insn,
                              int ops)
                       throws InvalidInstructionException

Throws:

InvalidInstructionException

assertOperandIsRegister

public void assertOperandIsRegister(ILOCInstruction insn,
                                    ILOCOperand op)
                             throws InvalidInstructionException

Throws:

InvalidInstructionException

assertAllRegOperands

public void assertAllRegOperands(ILOCInstruction insn,
                                 int regs)
                          throws InvalidInstructionException

Throws:

InvalidInstructionException

assertOperandType

public void assertOperandType(ILOCInstruction insn,
                              ILOCOperand op,
                              ILOCOperand.Type type)
                       throws InvalidInstructionException

Throws:

InvalidInstructionException

assertIsValid

public void assertIsValid(ILOCInstruction insn)
                   throws InvalidInstructionException

Throws:

InvalidInstructionException

handle

public boolean handle(ILOCInstruction insn)
               throws InvalidInstructionException

Throws:

InvalidInstructionException

getInt

public int getInt(ILOCOperand src)

setInt

public void setInt(ILOCOperand dst,
                   int value)

getBool

public boolean getBool(ILOCOperand src)

setBool

public void setBool(ILOCOperand dst,
                    int value)

setBool

public void setBool(ILOCOperand dst,
                    boolean value)

findJumpTarget

public int findJumpTarget(ILOCOperand targ)

storeInt

public void storeInt(int address,
                     int value)

loadInt

public int loadInt(int address)

push

public void push(int value)

pop

public int pop()

getReturnValue

public int getReturnValue()

checkStack

public void checkStack()

dumpSystemState

public void dumpSystemState()