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

   1 package era.mi.logic.components;
   2
   3 import java.util.List;
   4
   5 import era.mi.logic.Bit;
   6 import era.mi.logic.wires.Wire.WireEnd;
   7
   8 public class TriStateBuffer extends BasicComponent
   9 {
  10         WireEnd in, enable;
  11         WireEnd out;
  12
  13         public TriStateBuffer(int processTime, WireEnd in, WireEnd out, WireEnd enable)
  14         {
  15                 super(processTime);
  16                 if (in.length() != out.length())
  17                         throw new IllegalArgumentException(
  18                                         "Tri-state output must have the same amount of bits as the input. Input: " + in.length() + " Output: " + out.length());
  19                 if (enable.length() != 1)
  20                         throw new IllegalArgumentException("Tri-state enable must have exactly one bit, not " + enable.length() + ".");
  21                 this.in = in;
  22                 in.addObserver(this);
  23                 this.enable = enable;
  24                 enable.addObserver(this);
  25                 this.out = out;
  26         }
  27
  28         @Override
  29         protected void compute()
  30         {
  31                 if (enable.getValue() == Bit.ONE)
  32                         out.feedSignals(in.getValues());
  33                 else
  34                         out.clearSignals();
  35         }
  36
  37         @Override
  38         public List<WireEnd> getAllInputs()
  39         {
  40                 return List.of(in, enable);
  41         }
  42
  43         @Override
  44         public List<WireEnd> getAllOutputs()
  45         {
  46                 return List.of(out);
  47         }
  48
  49 }