net.mograsim.logic.core/src/net/mograsim/logic/core/components/CoreDemux.java

   1 package net.mograsim.logic.core.components;
   2
   3 import java.util.List;
   4
   5 import net.mograsim.logic.core.timeline.Timeline;
   6 import net.mograsim.logic.core.wires.CoreWire;
   7 import net.mograsim.logic.core.wires.CoreWire.ReadEnd;
   8 import net.mograsim.logic.core.wires.CoreWire.ReadWriteEnd;
   9
  10 /**
  11  * Models a multiplexer. Takes an arbitrary amount of input {@link CoreWire}s, one of which, as determined by select, is put through to the
  12  * output.
  13  *
  14  * @author Fabian Stemmler
  15  *
  16  */
  17 public class CoreDemux extends BasicCoreComponent
  18 {
  19         private final ReadEnd select, in;
  20         private final ReadWriteEnd[] outputs;
  21         private final int outputSize;
  22         private int selected = -1;
  23
  24         /**
  25          * Output {@link CoreWire}s and in must be of uniform width
  26          *
  27          * @param in      Must be of uniform width with all outputs.
  28          * @param select  Indexes the output array to which the input is mapped. Must have enough bits to index all outputs.
  29          * @param outputs One of these outputs receives the input signal, depending on the select bits
  30          */
  31         public CoreDemux(Timeline timeline, int processTime, ReadEnd in, ReadEnd select, ReadWriteEnd... outputs)
  32         {
  33                 super(timeline, processTime);
  34                 outputSize = in.width();
  35
  36                 this.in = in;
  37                 this.outputs = outputs;
  38                 for (int i = 0; i < this.outputs.length; i++)
  39                 {
  40                         if (outputs[i].width() != outputSize)
  41                                 throw new IllegalArgumentException("All DEMUX wire arrays must be of uniform width!");
  42                         this.outputs[i] = outputs[i];
  43                 }
  44
  45                 this.select = select;
  46                 select.registerObserver(this);
  47
  48                 int maxInputs = 1 << select.width();
  49                 if (this.outputs.length > maxInputs)
  50                         throw new IllegalArgumentException("There are more outputs (" + this.outputs.length + ") to the DEMUX than supported by "
  51                                         + select.width() + " select bits (" + maxInputs + ").");
  52                 in.registerObserver(this);
  53         }
  54
  55         @Override
  56         public void compute()
  57         {
  58                 int selectValue = select.hasNumericValue() ? (int) select.getUnsignedValue() : -1;
  59                 if (selectValue >= outputs.length)
  60                         selectValue = -1;
  61
  62                 if (selected != selectValue && selected != -1)
  63                         outputs[selected].clearSignals();
  64
  65                 selected = selectValue;
  66
  67                 if (selectValue != -1)
  68                         outputs[selectValue].feedSignals(in.getValues());
  69         }
  70
  71         @Override
  72         public List<ReadEnd> getAllInputs()
  73         {
  74                 return List.of(in, select);
  75         }
  76
  77         @Override
  78         public List<ReadWriteEnd> getAllOutputs()
  79         {
  80                 return List.of(outputs);
  81         }
  82 }