avrora.sim.util
Class SequenceProbe

java.lang.Object
  avrora.sim.util.SequenceProbe

All Implemented Interfaces:

Simulator.Probe

public class SequenceProbe

extends java.lang.Object

implements Simulator.Probe

The SequenceProbe is a probe composer that allows a probe to be fired for every instruction executed between a specified entrypoint and a specified exit point. For example, if the entrypoint is a call instruction and the exit point is the instruction following the call instruction, then the probe will fire for every instruction executed between the call and return, including both the call and the instruction following the call.

This probe supports nested entries (e.g. recursive calls). It is best used on pieces of the program that are single-entry/single-exit such as calls, interrupts, basic blocks, and SSE regions of control flow graphs. It does not work well for loops because of the nesting behavior.

Field Summary

int	entry_addr The immutable entry_addr field stores the address that enables the per-instruction calling of the probe passed in the constructor.
int	exit_addr The immutable exit_addr field stores the address that disables the per-instruction calling of the probe passed when the nesting level reaches zero.
int	nesting The nesting field stores the current nesting level (i.e. the number of times entry_addr has been reached without exit_addr intervening).
Simulator.Probe	probe The immutable probe field stores a reference to the probe passed in the constructor.

Constructor Summary

SequenceProbe(Simulator.Probe p, int entry, int exit)
The constructor for the SequenceProbe class simply stores its arguments into the corresponding public final fields in this object, leaving the probe in a state where it is ready to be inserted into a simulator.

Method Summary

void	fireAfter(Instr i, int address, State state) The fireBefore() method is called before the probed instruction executes.
void	fireBefore(Instr i, int address, State state) The fireBefore() method is called before the probed instruction executes.
void	reset() The reset() method simply resets the nesting level of the sequence probe, as if it had exited from all nested entries into the region.

Methods inherited from class java.lang.Object

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

Field Detail

entry_addr

public final int entry_addr

The immutable entry_addr field stores the address that enables the per-instruction calling of the probe passed in the constructor.

exit_addr

public final int exit_addr

The immutable exit_addr field stores the address that disables the per-instruction calling of the probe passed when the nesting level reaches zero.

probe

public final Simulator.Probe probe

The immutable probe field stores a reference to the probe passed in the constructor.

nesting

public int nesting

The nesting field stores the current nesting level (i.e. the number of times entry_addr has been reached without exit_addr intervening).

Constructor Detail

SequenceProbe

public SequenceProbe(Simulator.Probe p,
                     int entry,
                     int exit)

The constructor for the SequenceProbe class simply stores its arguments into the corresponding public final fields in this object, leaving the probe in a state where it is ready to be inserted into a simulator.

Parameters:

p - the probe to fire for each instruction when the sequence is entered

entry - the byte address of the entrypoint to the sequence

exit - the byte address of the exitpoint of the sequence

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 sequence probe, if the address is the entrypoint address, then the nesting level is incremented. When the nesting level is greater than one, then the sequence probe will delegate the fireBefore() call to the user probe.

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 fireBefore() method is called before the probed instruction executes. When the nesting level is greater than one, then the sequence probe will delegate the fireAfter() call to the user probe. If the address is the exit point, then the nesting level is decremented after the call to fireAfter() of the user probe.

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

reset

public void reset()

The reset() method simply resets the nesting level of the sequence probe, as if it had exited from all nested entries into the region.