Slight improvements of Wire#fuse(...)

diff --git a/net.mograsim.logic.core/src/net/mograsim/logic/core/wires/Wire.java b/net.mograsim.logic.core/src/net/mograsim/logic/core/wires/Wire.java
index e2f7c33..4063d78 100644 (file)
--- a/net.mograsim.logic.core/src/net/mograsim/logic/core/wires/Wire.java
+++ b/net.mograsim.logic.core/src/net/mograsim/logic/core/wires/Wire.java
@@ -30,7 +30,7 @@ public class Wire
        List<ReadWriteEnd> inputs = new ArrayList<>();
        Timeline timeline;
        private Bit[] bitsWithoutFusions;
-       FusionedBit[] fusedBits;
+       FusedBit[] fusedBits;
 
        public Wire(Timeline timeline, int width, int travelTime)
        {
@@ -65,7 +65,7 @@ public class Wire
        {
                invalidateCachedValues();
                if (fusedBits != null)
-                       for (FusionedBit fusion : fusedBits)
+                       for (FusedBit fusion : fusedBits)
                                if (fusion != null)
                                        fusion.invalidateCachedValuesForAllParticipatingWires();
        }
@@ -104,7 +104,7 @@ public class Wire
                        bits = new Bit[width];
                        for (int i = 0; i < width; i++)
                        {
-                               FusionedBit fusion = fusedBits[i];
+                               FusedBit fusion = fusedBits[i];
                                if (fusion == null)
                                        bits[i] = bitsWithoutFusions[i];
                                else
@@ -623,20 +623,9 @@ public class Wire
         */
        public static void fuse(Wire a, Wire b, int fromA, int fromB, int width)
        {
-               // TODO checks
-               for (int i = 0; i < width; i++)
+               // iterate in this direction to be fail-fast (rely on the checks in fuse(Wire, Wire, int, int)
+               for (int i = width - 1; i >= 0; i--)
                        fuse(a, b, fromA + i, fromB + i);
-//             ReadWriteEnd rA = a.createReadWriteEnd(), rB = b.createReadWriteEnd();
-//             rA.registerObserver(x -> rB.feedSignals(fromB, rA.wireValuesExcludingMe().subVector(fromA, fromA + width)));
-//             rB.registerObserver(x -> rA.feedSignals(fromA, rB.wireValuesExcludingMe().subVector(fromB, fromB + width)));
-//
-//             rA.setValues(0, BitVector.of(Bit.Z, fromA));
-//             rB.setValues(0, BitVector.of(Bit.Z, fromB));
-//             rA.setValues(fromA + width, BitVector.of(Bit.Z, a.width - width - fromA));
-//             rB.setValues(fromB + width, BitVector.of(Bit.Z, b.width - width - fromB));
-//
-//             rA.notifyObservers();
-//             rB.notifyObservers();
        }
 
        /**
@@ -650,16 +639,20 @@ public class Wire
         */
        private static void fuse(Wire a, Wire b, int bitA, int bitB)
        {
+               if (bitA >= a.width)
+                       throw new IllegalArgumentException("No bit " + bitA + " in " + a + " (width " + a.width + ")");
+               if (bitB >= b.width)
+                       throw new IllegalArgumentException("No bit " + bitB + " in " + b + " (width " + b.width + ")");
                if (a.fusedBits == null)
-                       a.fusedBits = new FusionedBit[a.width];
+                       a.fusedBits = new FusedBit[a.width];
                if (b.fusedBits == null)
-                       b.fusedBits = new FusionedBit[b.width];
-               FusionedBit oldFusionA = a.fusedBits[bitA];
-               FusionedBit oldFusionB = b.fusedBits[bitB];
+                       b.fusedBits = new FusedBit[b.width];
+               FusedBit oldFusionA = a.fusedBits[bitA];
+               FusedBit oldFusionB = b.fusedBits[bitB];
                if (oldFusionA == null)
                        if (oldFusionB == null)
                        {
-                               FusionedBit fusion = new FusionedBit();
+                               FusedBit fusion = new FusedBit();
                                fusion.addParticipatingWireBit(a, bitA);
                                fusion.addParticipatingWireBit(b, bitB);
                        } else
@@ -670,11 +663,11 @@ public class Wire
                        oldFusionA.mergeOtherIntoThis(oldFusionB);
        }
 
-       private static class FusionedBit
+       private static class FusedBit
        {
                private final List<WireBit> participatingWireBits;
 
-               public FusionedBit()
+               public FusedBit()
                {
                        this.participatingWireBits = new ArrayList<>();
                }
@@ -691,7 +684,7 @@ public class Wire
                        wb.wire.invalidateCachedValuesForAllFusedWires();
                }
 
-               public void mergeOtherIntoThis(FusionedBit other)
+               public void mergeOtherIntoThis(FusedBit other)
                {
                        for (WireBit wb : other.participatingWireBits)
                                addParticipatingWireBit(wb);
@@ -705,8 +698,6 @@ public class Wire
 
                public Bit getValue()
                {
-                       if (participatingWireBits.isEmpty())
-                               return Bit.U;
                        Bit result = null;
                        for (WireBit wb : participatingWireBits)
                                if (!wb.wire.inputs.isEmpty())