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.Wire;
   9 import era.mi.logic.wires.Wire.WireEnd;
  10
  11 public class TriStateBuffer extends BasicComponent
  12 {
  13         WireEnd in, enable;
  14         WireEnd out;
  15
  16         public TriStateBuffer(int processTime, WireEnd in, WireEnd out, WireEnd enable)
  17         {
  18                 super(processTime);
  19                 if (in.length() != out.length())
  20                         throw new IllegalArgumentException(
  21                                         "Tri-state output must have the same amount of bits as the input. Input: " + in.length() + " Output: " + out.length());
  22                 if (enable.length() != 1)
  23                         throw new IllegalArgumentException("Tri-state enable must have exactly one bit, not " + enable.length() + ".");
  24                 this.in = in;
  25                 in.addObserver(this);
  26                 this.enable = enable;
  27                 enable.addObserver(this);
  28                 this.out = out;
  29         }
  30
  31         @Override
  32         protected void compute()
  33         {
  34                 if (enable.getValue() == Bit.ONE)
  35                         out.feedSignals(in.getValues());
  36                 else
  37                         out.clearSignals();
  38         }
  39
  40         @Override
  41         public List<WireEnd> getAllInputs()
  42         {
  43                 return Collections.unmodifiableList(Arrays.asList(in, enable));
  44         }
  45
  46         @Override
  47         public List<WireEnd> getAllOutputs()
  48         {
  49                 return Collections.unmodifiableList(Arrays.asList(out));
  50         }
  51
  52 }