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.timeline.TimelineEventHandler;
   7 import net.mograsim.logic.core.types.BitVector;
   8 import net.mograsim.logic.core.wires.CoreWire;
   9 import net.mograsim.logic.core.wires.CoreWire.ReadEnd;
  10 import net.mograsim.logic.core.wires.CoreWire.ReadWriteEnd;
  11
  12 /**
  13  * Models a multiplexer. Takes an arbitrary amount of input {@link CoreWire}s, one of which, as determined by select, is put through to the
  14  * output.
  15  *
  16  * @author Fabian Stemmler
  17  *
  18  */
  19 public class CoreDemux extends BasicCoreComponent
  20 {
  21         private final ReadEnd select, in;
  22         private final ReadWriteEnd[] outputs;
  23         private final int outputSize;
  24         private int selected = -1;
  25
  26         /**
  27          * Output {@link CoreWire}s and in must be of uniform width
  28          *
  29          * @param in      Must be of uniform width with all outputs.
  30          * @param select  Indexes the output array to which the input is mapped. Must have enough bits to index all outputs.
  31          * @param outputs One of these outputs receives the input signal, depending on the select bits
  32          */
  33         public CoreDemux(Timeline timeline, int processTime, ReadEnd in, ReadEnd select, ReadWriteEnd... outputs)
  34         {
  35                 super(timeline, processTime);
  36                 outputSize = in.width();
  37
  38                 this.in = in;
  39                 this.outputs = outputs;
  40                 for (int i = 0; i < this.outputs.length; i++)
  41                 {
  42                         if (outputs[i].width() != outputSize)
  43                                 throw new IllegalArgumentException("All DEMUX wire arrays must be of uniform width!");
  44                         this.outputs[i] = outputs[i];
  45                 }
  46
  47                 this.select = select;
  48                 select.registerObserver(this);
  49
  50                 int maxInputs = 1 << select.width();
  51                 if (this.outputs.length > maxInputs)
  52                         throw new IllegalArgumentException("There are more outputs (" + this.outputs.length + ") to the DEMUX than supported by "
  53                                         + select.width() + " select bits (" + maxInputs + ").");
  54                 in.registerObserver(this);
  55         }
  56
  57         @Override
  58         public TimelineEventHandler compute()
  59         {
  60                 int selectValue = select.getValues().isBinary() ? (int) select.getValues().getUnsignedValueLong() : -1;
  61                 if (selectValue >= outputs.length)
  62                         selectValue = -1;
  63
  64                 boolean hasOldSelection = selected != selectValue && selected != -1;
  65                 int oldSelection = selected;
  66                 boolean hasNewSelection = selectValue != -1;
  67                 int newSelection = selectValue;
  68                 BitVector inputValues = in.getValues();
  69
  70                 selected = selectValue;
  71
  72                 return e ->
  73                 {
  74                         if (hasOldSelection)
  75                                 outputs[oldSelection].clearSignals();
  76                         if (hasNewSelection)
  77                                 outputs[newSelection].feedSignals(inputValues);
  78                 };
  79         }
  80
  81         @Override
  82         public List<ReadEnd> getAllInputs()
  83         {
  84                 return List.of(in, select);
  85         }
  86
  87         @Override
  88         public List<ReadWriteEnd> getAllOutputs()
  89         {
  90                 return List.of(outputs);
  91         }
  92 }