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

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