era.mi/src/era/mi/logic/components/TriStateBuffer.java

   1 package era.mi.logic.components;
   2
   3 import java.util.Arrays;
   4 import java.util.Collections;
   5 import java.util.List;
   6
   7 import era.mi.logic.Bit;
   8 import era.mi.logic.wires.WireArray;
   9 import era.mi.logic.wires.WireArray.WireArrayInput;
  10
  11 public class TriStateBuffer extends BasicComponent {
  12         WireArray in, enable;
  13         WireArrayInput outI;
  14
  15         public TriStateBuffer(int processTime, WireArray in, WireArray out, WireArray enable) {
  16                 super(processTime);
  17                 if (in.length != out.length)
  18                         throw new IllegalArgumentException(
  19                                         "Tri-state output must have the same amount of bits as the input. Input: " + in.length + " Output: " + out.length);
  20                 if (enable.length != 1)
  21                         throw new IllegalArgumentException("Tri-state enable must have exactly one bit, not " + enable.length + ".");
  22                 this.in = in;
  23                 in.addObserver(this);
  24                 this.enable = enable;
  25                 enable.addObserver(this);
  26                 outI = out.createInput();
  27         }
  28
  29         @Override
  30         protected void compute() {
  31                 if (enable.getValue() == Bit.ONE)
  32                         outI.feedSignals(in.getValues());
  33                 else
  34                         outI.clearSignals();
  35         }
  36
  37         @Override
  38         public List<WireArray> getAllInputs() {
  39                 return Collections.unmodifiableList(Arrays.asList(in, enable));
  40         }
  41
  42         @Override
  43         public List<WireArray> getAllOutputs() {
  44                 return Collections.unmodifiableList(Arrays.asList(outI.owner));
  45         }
  46
  47 }