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.types.Bit;
   6 import era.mi.logic.wires.Wire.ReadEnd;
   7 import era.mi.logic.wires.Wire.ReadWriteEnd;
   8
   9 public class TriStateBuffer extends BasicComponent
  10 {
  11         ReadEnd in, enable;
  12         ReadWriteEnd out;
  13
  14         public TriStateBuffer(int processTime, ReadEnd in, ReadWriteEnd out, ReadEnd enable)
  15         {
  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                 this.out = out;
  27         }
  28
  29         @Override
  30         protected void compute()
  31         {
  32                 if (enable.getValue() == Bit.ONE)
  33                         out.feedSignals(in.getValues());
  34                 else
  35                         out.clearSignals();
  36         }
  37
  38         @Override
  39         public List<ReadEnd> getAllInputs()
  40         {
  41                 return List.of(in, enable);
  42         }
  43
  44         @Override
  45         public List<ReadWriteEnd> getAllOutputs()
  46         {
  47                 return List.of(out);
  48         }
  49
  50 }