/* 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 Adder extends InstanceFactory {
static final int PER_DELAY = 1;
private static final int IN0 = 0;
private static final int IN1 = 1;
private static final int OUT = 2;
private static final int C_IN = 3;
private static final int C_OUT = 4;
public Adder() {
super("Adder", Strings.getter("adderComponent"));
setAttributes(new Attribute[] {
StdAttr.WIDTH
}, new Object[] {
BitWidth.create(8)
});
setKeyConfigurator(new BitWidthConfigurator(StdAttr.WIDTH));
setOffsetBounds(Bounds.create(-40, -20, 40, 40));
setIconName("adder.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[C_IN] = new Port(-20, -20, Port.INPUT, 1);
ps[C_OUT] = new Port(-20, 20, Port.INPUT, 1);
ps[IN0].setToolTip(Strings.getter("adderInputTip"));
ps[IN1].setToolTip(Strings.getter("adderInputTip"));
ps[OUT].setToolTip(Strings.getter("adderOutputTip"));
ps[C_IN].setToolTip(Strings.getter("adderCarryInTip"));
ps[C_OUT].setToolTip(Strings.getter("adderCarryOutTip"));
setPorts(ps);
}
@Override
public void propagate(InstanceState state) {
// get attributes
BitWidth dataWidth = state.getAttributeValue(StdAttr.WIDTH);
// compute outputs
Value a = state.getPort(IN0);
Value b = state.getPort(IN1);
Value c_in = state.getPort(C_IN);
Value[] outs = Adder.computeSum(dataWidth, a, b, c_in);
// propagate them
int delay = (dataWidth.getWidth() + 2) * PER_DELAY;
state.setPort(OUT, outs[0], delay);
state.setPort(C_OUT, outs[1], 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(C_IN, "c in", Direction.NORTH);
painter.drawPort(C_OUT, "c 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);
g.drawLine(x - 10, y - 5, x - 10, y + 5);
GraphicsUtil.switchToWidth(g, 1);
}
static Value[] computeSum(BitWidth width, Value a, Value b, Value c_in) {
int w = width.getWidth();
if (c_in == Value.UNKNOWN || c_in == Value.NIL) c_in = Value.FALSE;
if (a.isFullyDefined() && b.isFullyDefined() && c_in.isFullyDefined()) {
if (w >= 32) {
long mask = (1L << w) - 1;
long ax = (long) a.toIntValue() & mask;
long bx = (long) b.toIntValue() & mask;
long cx = (long) c_in.toIntValue() & mask;
long sum = ax + bx + cx;
return new Value[] { Value.createKnown(width, (int) sum),
((sum >> w) & 1) == 0 ? Value.FALSE : Value.TRUE };
} else {
int sum = a.toIntValue() + b.toIntValue() + c_in.toIntValue();
return new Value[] { Value.createKnown(width, sum),
((sum >> w) & 1) == 0 ? Value.FALSE : Value.TRUE };
}
} else {
Value[] bits = new Value[w];
Value carry = c_in;
for (int i = 0; i < w; i++) {
if (carry == Value.ERROR) {
bits[i] = Value.ERROR;
} else if (carry == Value.UNKNOWN) {
bits[i] = Value.UNKNOWN;
} else {
Value ab = a.get(i);
Value bb = b.get(i);
if (ab == Value.ERROR || bb == Value.ERROR) {
bits[i] = Value.ERROR;
carry = Value.ERROR;
} else if (ab == Value.UNKNOWN || bb == Value.UNKNOWN) {
bits[i] = Value.UNKNOWN;
carry = Value.UNKNOWN;
} else {
int sum = (ab == Value.TRUE ? 1 : 0)
+ (bb == Value.TRUE ? 1 : 0)
+ (carry == Value.TRUE ? 1 : 0);
bits[i] = (sum & 1) == 1 ? Value.TRUE : Value.FALSE;
carry = (sum >= 2) ? Value.TRUE : Value.FALSE;
}
}
}
return new Value[] { Value.create(bits), carry };
}
}
}