ISA
Class MemoryCell

java.lang.Object
  ISA.MemoryCell

Direct Known Subclasses:

Datum, Instruction

public abstract class MemoryCell
extends java.lang.Object

A cell of ISA-abstracted memory: an instruction or a data element. A MemoryCell serves two roles. First it is an immutable snapshot of an instruction or data element in real memory. A cell is created from a values in memory or from an opcode and set of operands. The memory region to which the cell belongs is responsible for tracking changes to the real memory that underlies the cell. When memory changes, the memory region creates new cell objects for those new memory values. When an instruction is created from an opcode and operand list, the region writes the cell's value into memory. Second is is a repository for auxiliary information about the cell that is not stored in MainMemory such as labels and comments. This information is not immutable. It can be changed without requiring a new MemoryCell.

Field Summary

protected int	address
protected BitString	checkpointValue
protected java.lang.String	comment
protected java.lang.String	label
protected Memory	memory
protected BitString	value

Constructor Summary

MemoryCell(Memory aMemory, int anAddress, BitString aValue, java.lang.String aLabel, java.lang.String aComment)

Method Summary

void	checkpointValue()
void	copyFrom(MemoryCell aCell)
boolean	equals(java.lang.Object o)
int	getAddress()
int	hashCode()
int	length()
void	restoreValueFromCheckpoint()

Methods inherited from class java.lang.Object

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

Field Detail

memory

protected Memory memory

address

protected int address

value

protected BitString value

label

protected java.lang.String label

comment

protected java.lang.String comment

checkpointValue

protected BitString checkpointValue

Constructor Detail

MemoryCell

public MemoryCell(Memory aMemory,
                  int anAddress,
                  BitString aValue,
                  java.lang.String aLabel,
                  java.lang.String aComment)

Method Detail

copyFrom

public void copyFrom(MemoryCell aCell)

checkpointValue

public void checkpointValue()

restoreValueFromCheckpoint

public void restoreValueFromCheckpoint()

getAddress

public int getAddress()

length

public int length()

equals

public boolean equals(java.lang.Object o)

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object