avrora.sim.util
Class BranchCounter

java.lang.Object
  avrora.sim.util.BranchCounter

All Implemented Interfaces:

Simulator.Probe

public class BranchCounter

extends java.lang.Object

implements Simulator.Probe

The BranchCounter class is a profiling probe that can be inserted at a branch instruction to count the number of times the branch is taken and not taken. It demonstrates the ability to inspect the state of the program after the execution of a program. It determines whether the branch was taken by inspecting the program counter of the new state. If the program counter is not equal to the instruction following the branch, then the branch was taken.

See Also:

Counter

Field Summary

int	nottakenCount This field tracks the number of times the branch is not taken.
int	takenCount This field tracks the number of times the branch is taken.

Constructor Summary

BranchCounter()

Method Summary

void	fireAfter(Instr i, int address, State state) The fireAfter() method is called after the probed instruction executes.
void	fireBefore(Instr i, int address, State state) The fireBefore() method is called before the probed instruction executes.

Methods inherited from class java.lang.Object

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

Field Detail

takenCount

public int takenCount

This field tracks the number of times the branch is taken. It is incremented in the fireAfter method if the branch was taken.

nottakenCount

public int nottakenCount

This field tracks the number of times the branch is not taken. It is incremented in the fireAfter method if the branch was not taken.

Constructor Detail

BranchCounter

public BranchCounter()

Method Detail

fireBefore

public void fireBefore(Instr i,
                       int address,
                       State state)

The fireBefore() method is called before the probed instruction executes. In the implementation of the branch counter, nothing needs to be done before the branch is executed, so this method does nothing.

Specified by:

fireBefore in interface Simulator.Probe

Parameters:

i - the instruction being probed

address - the address at which this instruction resides

state - the state of the simulation

fireAfter

public void fireAfter(Instr i,
                      int address,
                      State state)

The fireAfter() method is called after the probed instruction executes. In the implementation of the branch counter, the counter determines whether the branch was taken by inspecting the program counter of the new state. If the program counter is not equal to the instruction following the branch, then the branch was taken.

Specified by:

fireAfter in interface Simulator.Probe

Parameters:

i - the instruction being probed

address - the address at which this instruction resides

state - the state of the simulation