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