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

   1 package net.mograsim.logic.core.components;
   2
   3 import java.util.ArrayList;
   4 import java.util.Arrays;
   5 import java.util.Collections;
   6 import java.util.List;
   7
   8 import net.mograsim.logic.core.timeline.Timeline;
   9 import net.mograsim.logic.core.timeline.TimelineEventHandler;
  10 import net.mograsim.logic.core.types.BitVector;
  11 import net.mograsim.logic.core.wires.CoreWire;
  12 import net.mograsim.logic.core.wires.CoreWire.ReadEnd;
  13 import net.mograsim.logic.core.wires.CoreWire.ReadWriteEnd;
  14
  15 /**
  16  * Models a multiplexer. Takes an arbitrary amount of input {@link CoreWire}s, one of which, as determined by select, is put through to the
  17  * output.
  18  *
  19  * @author Fabian Stemmler
  20  *
  21  */
  22 public class CoreMux extends BasicCoreComponent
  23 {
  24         private ReadEnd select;
  25         private ReadWriteEnd out;
  26         private ReadEnd[] inputs;
  27         private final int outputSize;
  28
  29         /**
  30          * Input {@link CoreWire}s and out must be of uniform width
  31          *
  32          * @param out    Must be of uniform width with all inputs.
  33          * @param select Indexes the input array which is to be mapped to the output. Must have enough bits to index all inputs.
  34          * @param inputs One of these inputs is mapped to the output, depending on the select bits
  35          */
  36         public CoreMux(Timeline timeline, int processTime, ReadWriteEnd out, ReadEnd select, ReadEnd... inputs)
  37         {
  38                 super(timeline, processTime);
  39                 outputSize = out.width();
  40
  41                 this.inputs = inputs.clone();
  42                 for (int i = 0; i < this.inputs.length; i++)
  43                 {
  44                         if (inputs[i].width() != outputSize)
  45                                 throw new IllegalArgumentException("All MUX wire arrays must be of uniform width!");
  46                         inputs[i].registerObserver(this);
  47                 }
  48
  49                 this.select = select;
  50                 select.registerObserver(this);
  51
  52                 int maxInputs = 1 << select.width();
  53                 if (this.inputs.length > maxInputs)
  54                         throw new IllegalArgumentException("There are more inputs (" + this.inputs.length + ") to the MUX than supported by "
  55                                         + select.width() + " select bits (" + maxInputs + ").");
  56
  57                 this.out = out;
  58         }
  59
  60         public ReadEnd getOut()
  61         {
  62                 return out;
  63         }
  64
  65         public ReadEnd getSelect()
  66         {
  67                 return select;
  68         }
  69
  70         @Override
  71         public TimelineEventHandler compute()
  72         {
  73                 int selectValue;
  74                 if (!select.getValues().isBinary() || (selectValue = (int) select.getValues().getUnsignedValueLong()) >= inputs.length)
  75                 {
  76                         return e -> out.clearSignals();
  77                 }
  78
  79                 BitVector activeValues = inputs[selectValue].getValues();
  80                 return e -> out.feedSignals(activeValues);
  81         }
  82
  83         @Override
  84         public List<ReadEnd> getAllInputs()
  85         {
  86                 ArrayList<ReadEnd> wires = new ArrayList<>(Arrays.asList(inputs));
  87                 wires.add(select);
  88                 return Collections.unmodifiableList(wires);
  89         }
  90
  91         @Override
  92         public List<ReadWriteEnd> getAllOutputs()
  93         {
  94                 return List.of(out);
  95         }
  96 }