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/*
DrMIPS - Educational MIPS simulator
Copyright (C) 2013-2014 Bruno Nova <ei08109@fe.up.pt>
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package org.feup.brunonova.drmips.simulator.mips.components;
import java.util.Stack;
import org.feup.brunonova.drmips.simulator.exceptions.InvalidCPUException;
import org.feup.brunonova.drmips.simulator.mips.Data;
import org.feup.brunonova.drmips.simulator.mips.IsSynchronous;
import org.feup.brunonova.drmips.simulator.util.Point;
/**
* An ALU that supports multiplications and divisions, and contains the <tt>HI</tt> and <tt>LO</tt> "registers".
*
* @author Bruno Nova
*/
public class ExtendedALU extends ALU implements IsSynchronous {
private final Data hi, lo;
private final Stack<int[]> states = new Stack<int[]>(); // previous values
/**
* ALU constructor.
* @param id ALU's identifier.
* @param latency The latency of the component.
* @param position The component's position on the GUI.
* @param in1Id The identifier of the first input.
* @param in2Id The identifier of the second input.
* @param controlId The identifier of the control input.
* @param outId The identifier of the output
* @param zeroId The identifier of the zero output.
* @throws InvalidCPUException InvalidCPUException InvalidCPUException If <tt>id</tt> is empty or duplicated.
*/
public ExtendedALU(String id, int latency, Point position, String in1Id, String in2Id, String controlId, String outId, String zeroId) throws InvalidCPUException {
super(id, latency, position, in1Id, in2Id, controlId, outId, zeroId);
setNameKey("extended_alu");
setDescriptionKey("extended_alu_description");
hi = new Data();
lo = new Data();
}
@Override
public void executeSynchronous() {
controlALU.doSynchronousOperation(getInput1().getValue(), getInput2().getValue(), this, getControl().getValue());
}
@Override
public void pushState() {
states.push(new int[] {hi.getValue(), lo.getValue()});
}
@Override
public void popState() {
if(hasSavedStates()) {
int[] val = states.pop();
hi.setValue(val[0]);
lo.setValue(val[1]);
}
}
@Override
public boolean hasSavedStates() {
return !states.empty();
}
@Override
public void clearSavedStates() {
states.clear();
}
@Override
public void resetFirstState() {
while(hasSavedStates())
popState();
}
@Override
public boolean isWritingState() {
return controlALU.isWritingState(getControl().getValue());
}
/**
* Returns the <tt>HI</tt> "register".
* @return The <tt>HI</tt> "register".
*/
public final Data getHI() {
return hi;
}
/**
* Returns the <tt>HI</tt> "register".
* @return The <tt>HI</tt> "register".
*/
public final Data getLO() {
return lo;
}
/**
* Resets the <tt>HI</tt> and <tt>LO</tt> registers to 0.
*/
public final void reset() {
hi.setValue(0);
lo.setValue(0);
}
}
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