package era.mi.logic.components;
-import era.mi.logic.Bit;
-import era.mi.logic.WireArray;
+import era.mi.logic.wires.WireArray;
+import era.mi.logic.wires.WireArray.WireArrayInput;
/**
- * Models a Multiplexer. A is selected when select bit is 1, B when select bit is 0. Outputs X otherwise.
- * @author Fabian
+ * Models a multiplexer. Takes an arbitrary amount of input {@link WireArray}s, one of which,
+ * as determined by select, is put through to the output.
+ * @author Fabian Stemmler
*
*/
public class Mux extends BasicComponent
{
- private WireArray a, b, out;
private WireArray select;
- private final int size;
-
+ private WireArrayInput outI;
+ private WireArray[] inputs;
+ private final int outputSize;
/**
- * {@link WireArray}s a, b and out must be of uniform length, select
- * @param a Must be of uniform length with b and out.
- * @param b Must be of uniform length with a and out.
- * @param select C
- * @param out Must be of uniform length with a and b.
+ * Input {@link WireArray}s and out must be of uniform length
+ * @param out Must be of uniform length with all inputs.
+ * @param select Indexes the input array which is to be mapped to the output. Must have enough bits
+ * to index all inputs.
+ * @param inputs One of these inputs is mapped to the output, depending on the select bits
*/
- public Mux(int processTime, WireArray a, WireArray b, WireArray select, WireArray out)
+ public Mux(int processTime, WireArray out, WireArray select, WireArray... inputs)
{
super(processTime);
- size = a.length();
- if(b.length() != out.length() || b.length() != size)
- throw new IllegalArgumentException("All MUX wire arrays must be of uniform length!");
- this.a = a;
- a.addObserver(this);
- this.b = b;
- b.addObserver(this);
- this.select = select;
- select.addObserver(this);
- this.out = out;
- }
-
- @Override
- protected void compute()
- {
- WireArray active = b;
- switch(select.getValue())
+ outputSize = out.length;
+
+ this.inputs = inputs.clone();
+ for(int i = 0; i < this.inputs.length; i++)
{
- case ONE:
- active = a;
- case ZERO:
- out.feedSignals(active.getValues());
- break;
- default:
- Bit[] newValues = new Bit[size];
- for(int i = 0; i < size; i++)
- newValues[i] = Bit.X;
- out.feedSignals(newValues);
+ if(inputs[i].length != outputSize)
+ throw new IllegalArgumentException("All MUX wire arrays must be of uniform length!");
+ inputs[i].addObserver(this);
}
+
+ this.select = select;
+ select.addObserver(this);
+
+ int maxInputs = 1 << select.length;
+ if(this.inputs.length > maxInputs)
+ throw new IllegalArgumentException("There are more inputs ("
+ + this.inputs.length + ") to the MUX than supported by "
+ + select.length + " select bits (" + maxInputs + ").");
+
+ outI = out.createInput();
}
-
- public WireArray getA()
- {
- return a;
- }
-
- public WireArray getB()
- {
- return b;
- }
-
+
public WireArray getOut()
{
- return out;
+ return outI.owner;
}
public WireArray getSelect()
{
return select;
}
+
+ @Override
+ public void compute() {
+ int selectValue;
+ if(!select.hasNumericValue() || (selectValue = (int) select.getUnsignedValue()) >= inputs.length)
+ {
+ outI.clearSignals();
+ return;
+ }
+
+ WireArray active = inputs[selectValue];
+ outI.feedSignals(active.getValues());
+ }
}