geneseo.cs.compiler
Interface RegisterTable

All Known Implementing Classes:

SparcRegisterTable

public interface RegisterTable

This interface defines how any object that tracks register usage (i.e., which registers are in use and which free) for a compiler should behave.

Method Summary

void	clear() Marks all registers as unused.
java.lang.String	findFree() Find a free register.
boolean	isFree(java.lang.String regName) Inquire whether a register is free.
void	markFree(java.lang.String regName) Marks a register as free.
void	markUsed(java.lang.String regName) Marks a register as used.

Method Detail

clear

public void clear()

Marks all registers as unused.

markUsed

public void markUsed(java.lang.String regName)

Marks a register as used.

Parameters:

regName - the name of the register to mark used.

markFree

public void markFree(java.lang.String regName)

Marks a register as free.

Parameters:

regName - the name of the register to make free.

isFree

public boolean isFree(java.lang.String regName)

Inquire whether a register is free.

Parameters:

regName - the name of the register.

Returns:

True if the register is free, false if it isn't or if no such register exists.

findFree

public java.lang.String findFree()
                          throws CompilerException

Find a free register.

Returns:

a string naming a free register.

Throws:

CompilerException - if no registers are free.