Subtractor.java

/*******************************************************************************
 * This file is part of logisim-evolution.
 *
 *   logisim-evolution 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.
 *
 *   logisim-evolution 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 logisim-evolution.  If not, see <http://www.gnu.org/licenses/>.
 *
 *   Original code by Carl Burch (http://www.cburch.com), 2011.
 *   Subsequent modifications by :
 *     + Haute École Spécialisée Bernoise
 *       http://www.bfh.ch
 *     + Haute École du paysage, d'ingénierie et d'architecture de Genève
 *       http://hepia.hesge.ch/
 *     + Haute École d'Ingénierie et de Gestion du Canton de Vaud
 *       http://www.heig-vd.ch/
 *   The project is currently maintained by :
 *     + REDS Institute - HEIG-VD
 *       Yverdon-les-Bains, Switzerland
 *       http://reds.heig-vd.ch
 *******************************************************************************/

package com.cburch.logisim.std.arith;

import java.awt.Color;
import java.awt.Graphics;

import com.bfh.logisim.designrulecheck.CorrectLabel;
import com.cburch.logisim.data.Attribute;
import com.cburch.logisim.data.AttributeSet;
import com.cburch.logisim.data.BitWidth;
import com.cburch.logisim.data.Bounds;
import com.cburch.logisim.data.Direction;
import com.cburch.logisim.data.Location;
import com.cburch.logisim.data.Value;
import com.cburch.logisim.instance.InstanceFactory;
import com.cburch.logisim.instance.InstancePainter;
import com.cburch.logisim.instance.InstanceState;
import com.cburch.logisim.instance.Port;
import com.cburch.logisim.instance.StdAttr;
import com.cburch.logisim.tools.key.BitWidthConfigurator;
import com.cburch.logisim.util.GraphicsUtil;

public class Subtractor extends InstanceFactory {
	private static final int IN0 = 0;
	private static final int IN1 = 1;
	private static final int OUT = 2;
	private static final int B_IN = 3;
	private static final int B_OUT = 4;

	public Subtractor() {
		super("Subtractor", Strings.getter("subtractorComponent"));
		setAttributes(new Attribute[] { StdAttr.WIDTH },
				new Object[] { BitWidth.create(8) });
		setKeyConfigurator(new BitWidthConfigurator(StdAttr.WIDTH));
		setOffsetBounds(Bounds.create(-40, -20, 40, 40));
		setIconName("subtractor.gif");

		Port[] ps = new Port[5];
		ps[IN0] = new Port(-40, -10, Port.INPUT, StdAttr.WIDTH);
		ps[IN1] = new Port(-40, 10, Port.INPUT, StdAttr.WIDTH);
		ps[OUT] = new Port(0, 0, Port.OUTPUT, StdAttr.WIDTH);
		ps[B_IN] = new Port(-20, -20, Port.INPUT, 1);
		ps[B_OUT] = new Port(-20, 20, Port.OUTPUT, 1);
		ps[IN0].setToolTip(Strings.getter("subtractorMinuendTip"));
		ps[IN1].setToolTip(Strings.getter("subtractorSubtrahendTip"));
		ps[OUT].setToolTip(Strings.getter("subtractorOutputTip"));
		ps[B_IN].setToolTip(Strings.getter("subtractorBorrowInTip"));
		ps[B_OUT].setToolTip(Strings.getter("subtractorBorrowOutTip"));
		setPorts(ps);
	}

	@Override
	public String getHDLName(AttributeSet attrs) {
		StringBuffer CompleteName = new StringBuffer();
		if (attrs.getValue(StdAttr.WIDTH).getWidth() == 1)
			CompleteName.append("FullSubtractor");
		else
			CompleteName.append(CorrectLabel.getCorrectLabel(this.getName()));
		return CompleteName.toString();
	}

	@Override
	public boolean HDLSupportedComponent(String HDLIdentifier,
			AttributeSet attrs) {
		if (MyHDLGenerator == null)
			MyHDLGenerator = new SubtractorHDLGeneratorFactory();
		return MyHDLGenerator.HDLTargetSupported(HDLIdentifier, attrs);
	}

	@Override
	public void paintInstance(InstancePainter painter) {
		Graphics g = painter.getGraphics();
		painter.drawBounds();

		g.setColor(Color.GRAY);
		painter.drawPort(IN0);
		painter.drawPort(IN1);
		painter.drawPort(OUT);
		painter.drawPort(B_IN, "b in", Direction.NORTH);
		painter.drawPort(B_OUT, "b out", Direction.SOUTH);

		Location loc = painter.getLocation();
		int x = loc.getX();
		int y = loc.getY();
		GraphicsUtil.switchToWidth(g, 2);
		g.setColor(Color.BLACK);
		g.drawLine(x - 15, y, x - 5, y);
		GraphicsUtil.switchToWidth(g, 1);
	}

	@Override
	public void propagate(InstanceState state) {
		// get attributes
		BitWidth data = state.getAttributeValue(StdAttr.WIDTH);

		// compute outputs
		Value a = state.getPortValue(IN0);
		Value b = state.getPortValue(IN1);
		Value b_in = state.getPortValue(B_IN);
		if (b_in == Value.UNKNOWN || b_in == Value.NIL)
			b_in = Value.FALSE;
		Value[] outs = Adder.computeSum(data, a, b.not(), b_in.not());

		// propagate them
		int delay = (data.getWidth() + 4) * Adder.PER_DELAY;
		state.setPort(OUT, outs[0], delay);
		state.setPort(B_OUT, outs[1].not(), delay);
	}
}