Switch gate watchers to notify on input mask changes, add DivideByNCounter

StoneRed.LogicSimulator.Simulation/CycleCircuitSimulator.cs

@@ -17,6 +17,7 @@ public sealed class CycleCircuitSimulator : SimulatorBase
     private int[] nextInputMasks = [];
     private Action<int[], int[], int[]> computeOutputs = (_, _, _) => { };
     private int[] previousOutputMasks = [];
+    private int[] previousInputMasks = [];
 
     /// <summary>
     /// Ensures internal storage arrays are properly sized for the current gate count.
@@ -28,6 +29,7 @@ public sealed class CycleCircuitSimulator : SimulatorBase
         {
             nextInputMasks = new int[gateKinds.Count];
             previousOutputMasks = new int[gateKinds.Count];
+            previousInputMasks = new int[gateKinds.Count];
         }
     }
 
@@ -39,6 +41,7 @@ public sealed class CycleCircuitSimulator : SimulatorBase
         base.Reset();
         Array.Clear(nextInputMasks);
         Array.Clear(previousOutputMasks);
+        Array.Clear(previousInputMasks);
     }
 
     /// <summary>
@@ -55,10 +58,14 @@ public sealed class CycleCircuitSimulator : SimulatorBase
 
         (outputMasks, previousOutputMasks) = (previousOutputMasks, outputMasks);
         computeOutputs(inputMasks, outputMasks, sourceStates);
+        if (hasAnyWatchers)
+        {
+            Array.Copy(inputMasks, previousInputMasks, inputMasks.Length);
+        }
         PropagateAndSwap();
         if (hasAnyWatchers)
         {
-            NotifyAllWatchers(previousOutputMasks);
+            NotifyAllWatchers(previousInputMasks);
         }
     }
 
@@ -136,10 +143,14 @@ public sealed class CycleCircuitSimulator : SimulatorBase
             steps++;
             (outputMasks, previousOutputMasks) = (previousOutputMasks, outputMasks);
             computeOutputs(inputMasks, outputMasks, sourceStates);
+            if (hasAnyWatchers)
+            {
+                Array.Copy(inputMasks, previousInputMasks, inputMasks.Length);
+            }
             changed = PropagateAndSwapDetectChange();
             if (hasAnyWatchers)
             {
-                NotifyAllWatchers(previousOutputMasks);
+                NotifyAllWatchers(previousInputMasks);
             }
         }
         return !changed;

StoneRed.LogicSimulator.Simulation/EventCircuitSimulator.cs

@@ -84,7 +84,6 @@ public sealed class EventCircuitSimulator : SimulatorBase
             if (outputMasks[gateId] != oldOutput)
             {
                 Propagate(gateId);
-                NotifyGateWatchers(gateId);
             }
         }
     }
@@ -103,6 +102,10 @@ public sealed class EventCircuitSimulator : SimulatorBase
             if (oldBit != outVal)
             {
                 inputMasks[toGate] ^= 1 << bit;
+                if (hasAnyWatchers)
+                {
+                    NotifyGateWatchers(toGate);
+                }
                 Enqueue(toGate);
             }
         }

StoneRed.LogicSimulator.Simulation/ICircuitSimulator.cs

@@ -114,11 +114,11 @@ public interface ICircuitSimulator
     bool TryRunUntilStable(int maxSteps, out int steps);
 
     /// <summary>
-    /// Subscribes to output changes on a specific gate.
-    /// The callback is invoked whenever the gate's output value changes.
+    /// Subscribes to input mask changes on a specific gate.
+    /// The callback is invoked whenever the gate's input mask changes.
     /// </summary>
     /// <param name="gateId">The gate ID to watch.</param>
-    /// <param name="callback">Action to invoke on change. Parameters are (gateId, newOutputMask).</param>
+    /// <param name="callback">Action to invoke on change. Parameters are (gateId, newInputMask).</param>
     /// <returns>An <see cref="IDisposable"/> that unsubscribes the watcher when disposed.</returns>
     /// <exception cref="ArgumentNullException">Thrown when callback is null.</exception>
     /// <exception cref="ArgumentOutOfRangeException">Thrown when gateId is invalid.</exception>

StoneRed.LogicSimulator.Simulation/SimulatorBase.cs

@@ -246,18 +246,18 @@ public abstract class SimulatorBase : ICircuitSimulator
     }
 
     /// <summary>
-    /// Notifies all registered watchers of gates that changed between the previous and current output states.
+    /// Notifies all registered watchers of gates that changed between the previous and current input states.
     /// </summary>
-    /// <param name="previousOutputMasks">The output states from before the change.</param>
-    protected void NotifyAllWatchers(int[] previousOutputMasks)
+    /// <param name="previousInputMasks">The input states from before the change.</param>
+    protected void NotifyAllWatchers(int[] previousInputMasks)
     {
         for (int i = 0; i < gatesWithWatchers.Length; i++)
         {
             int gateId = gatesWithWatchers[i];
-            if (outputMasks[gateId] != previousOutputMasks[gateId])
+            if (inputMasks[gateId] != previousInputMasks[gateId])
             {
                 Action<int, int>[] callbacks = watcherCache[gateId];
-                int val = outputMasks[gateId];
+                int val = inputMasks[gateId];
                 for (int j = 0; j < callbacks.Length; j++)
                 {
                     callbacks[j](gateId, val);
@@ -267,7 +267,7 @@ public abstract class SimulatorBase : ICircuitSimulator
     }
 
     /// <summary>
-    /// Notifies watchers of a specific gate that its output has changed.
+    /// Notifies watchers of a specific gate that its input has changed.
     /// </summary>
     /// <param name="gateId">The ID of the gate that changed.</param>
     protected void NotifyGateWatchers(int gateId)
@@ -283,7 +283,7 @@ public abstract class SimulatorBase : ICircuitSimulator
             return;
         }
 
-        int val = outputMasks[gateId];
+        int val = inputMasks[gateId];
         for (int i = 0; i < callbacks.Length; i++)
         {
             callbacks[i](gateId, val);