Bug fix split/merge: Utilise new merge bits function to compute actual output value of B/D bits.

Note that this still isn't completely accurate to real-life because split-merge is wires which should back-propagate, but (as noted in comments in the code) we can't quite simulate reality.

Author: Edward Nutting

src/com/modsim/modules/SplitMerge.java

@@ -236,11 +236,11 @@ else if (   portB0.wasUpdated() || portB1.wasUpdated() ||
             a1_val.setBit(0, b2_val.getBit(0)); // c0-B0
 
             // Resolution of 3-state logic for merges
-            int val = b2_val.getBit(1) | b3_val.getBit(0);
+            int val = BinData.mergeBits(b2_val.getBit(1), b3_val.getBit(0));
             a1_val.setBit(1, val);
             a0_val.setBit(3, val);
 
-            val = b0_val.getBit(1) | b1_val.getBit(0);
+            val = BinData.mergeBits(b0_val.getBit(1), b1_val.getBit(0));
             a0_val.setBit(1, val);
         }