/* 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.Graphics;
import com.cburch.logisim.data.Attribute;
import com.cburch.logisim.data.AttributeSet;
import com.cburch.logisim.data.Attributes;
import com.cburch.logisim.data.BitWidth;
import com.cburch.logisim.data.Bounds;
import com.cburch.logisim.data.Location;
import com.cburch.logisim.data.Value;
import com.cburch.logisim.instance.Instance;
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.tools.key.IntegerConfigurator;
import com.cburch.logisim.tools.key.JoinedConfigurator;
import com.cburch.logisim.util.GraphicsUtil;
public class BitAdder extends InstanceFactory {
static final Attribute<Integer> NUM_INPUTS
= Attributes.forIntegerRange("inputs", Strings.getter("gateInputsAttr"), 1, 32);
public BitAdder() {
super("BitAdder", Strings.getter("bitAdderComponent"));
setAttributes(new Attribute[] {
StdAttr.WIDTH, NUM_INPUTS
}, new Object[] {
BitWidth.create(8), Integer.valueOf(1)
});
setKeyConfigurator(JoinedConfigurator.create(
new IntegerConfigurator(NUM_INPUTS, 1, 32, 0),
new BitWidthConfigurator(StdAttr.WIDTH)));
setIconName("bitadder.gif");
}
@Override
public Bounds getOffsetBounds(AttributeSet attrs) {
int inputs = attrs.getValue(NUM_INPUTS).intValue();
int h = Math.max(40, 10 * inputs);
int y = inputs < 4 ? 20 : (((inputs - 1) / 2) * 10 + 5);
return Bounds.create(-40, -y, 40, h);
}
@Override
protected void configureNewInstance(Instance instance) {
configurePorts(instance);
instance.addAttributeListener();
}
@Override
protected void instanceAttributeChanged(Instance instance, Attribute<?> attr) {
if (attr == StdAttr.WIDTH) {
configurePorts(instance);
} else if (attr == NUM_INPUTS) {
configurePorts(instance);
instance.recomputeBounds();
}
}
private void configurePorts(Instance instance) {
BitWidth inWidth = instance.getAttributeValue(StdAttr.WIDTH);
int inputs = instance.getAttributeValue(NUM_INPUTS).intValue();
int outWidth = computeOutputBits(inWidth.getWidth(), inputs);
int y;
int dy = 10;
switch (inputs) {
case 1: y = 0; break;
case 2: y = -10; dy = 20; break;
case 3: y = -10; break;
default: y = ((inputs - 1) / 2) * -10;
}
Port[] ps = new Port[inputs + 1];
ps[0] = new Port(0, 0, Port.OUTPUT, BitWidth.create(outWidth));
ps[0].setToolTip(Strings.getter("bitAdderOutputManyTip"));
for (int i = 0; i < inputs; i++) {
ps[i + 1] = new Port(-40, y + i * dy, Port.INPUT, inWidth);
ps[i + 1].setToolTip(Strings.getter("bitAdderInputTip"));
}
instance.setPorts(ps);
}
private int computeOutputBits(int width, int inputs) {
int maxBits = width * inputs;
int outWidth = 1;
while ((1 << outWidth) <= maxBits) outWidth++;
return outWidth;
}
@Override
public void propagate(InstanceState state) {
int width = state.getAttributeValue(StdAttr.WIDTH).getWidth();
int inputs = state.getAttributeValue(NUM_INPUTS).intValue();
// compute the number of 1 bits
int minCount = 0; // number that are definitely 1
int maxCount = 0; // number that are definitely not 0 (incl X/Z)
for (int i = 1; i <= inputs; i++) {
Value v = state.getPort(i);
Value[] bits = v.getAll();
for (int j = 0; j < bits.length; j++) {
Value b = bits[j];
if (b == Value.TRUE) minCount++;
if (b != Value.FALSE) maxCount++;
}
}
// compute which output bits should be error bits
int unknownMask = 0;
for (int i = minCount + 1; i <= maxCount; i++) {
unknownMask |= (minCount ^ i);
}
Value[] out = new Value[computeOutputBits(width, inputs)];
for (int i = 0; i < out.length; i++) {
if (((unknownMask >> i) & 1) != 0) {
out[i] = Value.ERROR;
} else if (((minCount >> i) & 1) != 0) {
out[i] = Value.TRUE;
} else {
out[i] = Value.FALSE;
}
}
int delay = out.length * Adder.PER_DELAY;
state.setPort(0, Value.create(out), delay);
}
@Override
public void paintInstance(InstancePainter painter) {
Graphics g = painter.getGraphics();
painter.drawBounds();
painter.drawPorts();
GraphicsUtil.switchToWidth(g, 2);
Location loc = painter.getLocation();
int x = loc.getX() - 10;
int y = loc.getY();
g.drawLine(x - 2, y - 5, x - 2, y + 5);
g.drawLine(x + 2, y - 5, x + 2, y + 5);
g.drawLine(x - 5, y - 2, x + 5, y - 2);
g.drawLine(x - 5, y + 2, x + 5, y + 2);
}
}