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