Added Parity Task (for completeness' sake), fixed SWMODE bank switching logic for 2K ROM, minor tweaks.

Contralto/AltoSystem.cs

@@ -172,7 +172,7 @@ namespace Contralto
     
         private void T_Elapsed(object sender, ElapsedEventArgs e)
         {
-            //System.Console.WriteLine("{0} CPU clocks/sec %{1}. {2} fields/sec", _clocks, ((double)_clocks / 5882353.0) * 100.0, _displayController.Fields);
+            System.Console.WriteLine("{0} CPU clocks/sec %{1}. {2} fields/sec", _clocks, ((double)_clocks / 5882353.0) * 100.0, _displayController.Fields);
             _clocks = 0;
             _displayController.Fields = 0;
         }

Contralto/CPU/CPU.cs

@@ -32,6 +32,7 @@ namespace Contralto.CPU
             _tasks[(int)TaskType.Cursor] = new CursorTask(this);
             _tasks[(int)TaskType.MemoryRefresh] = new MemoryRefreshTask(this);
             _tasks[(int)TaskType.Ethernet] = new EthernetTask(this);
+            _tasks[(int)TaskType.Parity] = new ParityTask(this);
 
             Reset();
         }

Contralto/CPU/Tasks/ParityTask.cs

@@ -0,0 +1,20 @@
+using System;
+
+namespace Contralto.CPU
+{
+    public partial class AltoCPU
+    {
+        /// <summary>
+        /// ParityTask is provided for completeness only, and implements the logic for the Parity task.
+        /// The Parity Task will never actually be woken because I'm not planning on emulating faulty memory.
+        /// </summary>
+        private sealed class ParityTask : Task
+        {
+            public ParityTask(AltoCPU cpu) : base(cpu)
+            {
+                _taskType = TaskType.Parity;                
+                _wakeup = false;
+            }            
+        }
+    }
+}

Contralto/CPU/Tasks/Task.cs

@@ -416,7 +416,8 @@ namespace Contralto.CPU
                 if (swMode)
                 {
                     //Console.WriteLine("SWMODE NEXT {0} Modifier {1}", Conversion.ToOctal(instruction.NEXT), Conversion.ToOctal(nextModifier));
-                    UCodeMemory.SwitchMode((ushort)(instruction.NEXT | nextModifier), _taskType);
+                    UCodeMemory.SwitchMode((ushort)(instruction.NEXT), _taskType);
+                    Logging.Log.Write(Logging.LogComponent.Microcode, "SWMODE: uPC {0}, next uPC {1}", Conversion.ToOctal(_mpc), Conversion.ToOctal(instruction.NEXT | nextModifier));
                 }
 
                 //

Contralto/CPU/UCodeMemory.cs

@@ -6,10 +6,10 @@ namespace Contralto.CPU
     public enum MicrocodeBank
     {
         ROM0 = 0,
-        ROM1,
-        RAM0,
-        RAM1,
-        RAM2
+        ROM1 = 1,
+        RAM0 = 2,
+        RAM1 = 3,
+        RAM2 = 4
     }
 
     struct RomFile
@@ -123,8 +123,7 @@ namespace Contralto.CPU
         {                        
             Logging.Log.Write(Logging.LogComponent.Microcode, "SWMODE: Current Bank {0}", _microcodeBank[(int)task]);
             
-            // 2K ROM                        
-            /*
+            // 2K ROM                                    
             switch(_microcodeBank[(int)task])
             {
                 case MicrocodeBank.ROM0:
@@ -138,10 +137,10 @@ namespace Contralto.CPU
                 case MicrocodeBank.RAM0:
                     _microcodeBank[(int)task] = (nextAddress & 0x100) == 0 ? MicrocodeBank.ROM0 : MicrocodeBank.ROM1;
                     break;
-            }*/
+            }
 
-            // for 1K ROM
-            _microcodeBank[(int)task] = _microcodeBank[(int)task] == MicrocodeBank.ROM0 ? MicrocodeBank.RAM0 : MicrocodeBank.ROM0;
+            // for 1K ROM -- todo: make configurable
+            //_microcodeBank[(int)task] = _microcodeBank[(int)task] == MicrocodeBank.ROM0 ? MicrocodeBank.RAM0 : MicrocodeBank.ROM0;
 
             Logging.Log.Write(Logging.LogComponent.Microcode, "SWMODE: New Bank {0} for Task {1}", _microcodeBank[(int)task], task);            
         }
@@ -152,8 +151,7 @@ namespace Contralto.CPU
             {
                 throw new NotImplementedException("Read from microcode ROM not implemented.");
             }            
-
-            // pretend no ram for the moment                
+                         
             Logging.Log.Write(Logging.LogComponent.Microcode, "CRAM address for read: Bank {0}, RAM {1}, lowhalf {2} addr {3}",
                 _ramBank,
                 _ramSelect,

Contralto/Contralto.csproj

@@ -80,6 +80,7 @@
     <Compile Include="CPU\ConstantMemory.cs" />
     <Compile Include="CPU\CPU.cs" />
     <Compile Include="CPU\NovaDisassembler.cs" />
+    <Compile Include="CPU\Tasks\ParityTask.cs" />
     <Compile Include="CPU\Tasks\EthernetTask.cs" />
     <Compile Include="CPU\Tasks\DisplayVerticalTask.cs" />
     <Compile Include="CPU\Tasks\DisplayHorizontalTask.cs" />

Contralto/Logging/Log.cs

@@ -75,8 +75,6 @@ namespace Contralto.Logging
             }
         }
 
-
-
         private static LogComponent _components;
         private static LogType _type;
     }