/* Copyright (c) 2010, Carl Burch. License information is located in the
* com.cburch.logisim.Main source code and at www.cburch.com/logisim/. */
package com.cburch.logisim.std.arith;
import java.awt.Color;
import java.awt.Graphics;
import com.cburch.logisim.data.Attribute;
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 void propagate(InstanceState state) {
// get attributes
BitWidth data = state.getAttributeValue(StdAttr.WIDTH);
// compute outputs
Value a = state.getPort(IN0);
Value b = state.getPort(IN1);
Value b_in = state.getPort(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);
}
@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);
}
}