- Fixed two memory state machine issues:

1) The Orbit microcode occasionally expects to be able to do a double-word read in cycles 6 and 7 instead of the usual 5 and 6.
  2) The double-word logic incorrectly handles several species of overlapped read/writes, which Spruce's layout microcode uses.

As a result, Spruce now works, as do the Smalltalk-80 images.

Several tweaks to microcode disassembly (still rough).

Completed Orbit / Dover ROS / Dover Print Engine emulation.  Still some rough edges; it works and can create PDF output.

Tweaked Disk Controller's Restore operation, it is now more accurate though wasn't causing any noticable issues.

Contralto/AltoSystem.cs

@@ -242,8 +242,6 @@ namespace Contralto
             get { return _scheduler; }
         }
 
-        public int _novaInst;        
-
         private AltoCPU _cpu;
         private MemoryBus _memBus;
         private Memory.Memory _mem;

Contralto/App.config

@@ -58,6 +58,15 @@
             <setting name="AudioDACCapturePath" serializeAs="String">
                 <value />
             </setting>
+            <setting name="EnablePrinting" serializeAs="String">
+                <value>False</value>
+            </setting>
+            <setting name="PrintOutputPath" serializeAs="String">
+                <value />
+            </setting>
+            <setting name="ReversePageOrder" serializeAs="String">
+                <value>True</value>
+            </setting>
         </Contralto.Properties.Settings>
     </userSettings>
 </configuration>

Contralto/CPU/CPU.cs

@@ -160,7 +160,7 @@ namespace Contralto.CPU
 
                 case InstructionCompletion.MemoryWait:
                     // We were waiting for memory on this cycle, we do nothing
-                    // (no task switch even if one is pending) in this case.                    
+                    // (no task switch even if one is pending) in this case.
                     break;
             }            
         }
@@ -187,13 +187,13 @@ namespace Contralto.CPU
             UCodeMemory.LoadBanksFromRMR(_rmr);
 
             // Reset RMR after reset.
-            _rmr = 0x0;         
+            _rmr = 0xffff;
           
             // Start in Emulator
             _currentTask = _tasks[0];
 
             //
-            // TODO:
+            // TODO: 
             // This is a hack of sorts, it ensures that the sector task initializes
             // itself as soon as the Emulator task yields after the reset.  (CopyDisk is broken otherwise due to the
             // sector task stomping over the KBLK CopyDisk sets up after the reset.  This is a race of sorts.)
@@ -201,6 +201,7 @@ namespace Contralto.CPU
             // in play that are not understood.
             //
             WakeupTask(CPU.TaskType.DiskSector);
+            BlockTask(CPU.TaskType.DiskWord);
         }
 
         /// <summary>
@@ -250,7 +251,20 @@ namespace Contralto.CPU
         public Task NextTask
         {
             get { return _nextTask; }
-        }        
+        }
+
+        public bool InternalBreak
+        {
+            get
+            {
+                return _internalBreak;
+            }
+
+            set
+            {
+                _internalBreak = value;
+            }
+        }
 
         private void TaskSwitch()
         {            
@@ -295,6 +309,8 @@ namespace Contralto.CPU
         private Task[] _tasks = new Task[16];                
 
         // The system this CPU belongs to
-        private AltoSystem _system;        
+        private AltoSystem _system;
+
+        private bool _internalBreak;
     }
 }

Contralto/CPU/Tasks/EmulatorTask.cs

@@ -111,7 +111,7 @@ namespace Contralto.CPU
                         // bus specifies the initial mode of task 15, the highest priority task(recall that task i starts at location i; the
                         // reset mode register determines only which microinstruction bank will be used at the outset). A task will
                         // commence in ROM0 if its associated bit in the reset mode register contains the value 1; otherwise it will
-                        // start in RAM0.Upon initial power - up of the Alto, and after each reset operation, the reset mode register
+                        // start in RAM0.  Upon initial power-up of the Alto, and after each reset operation, the reset mode register
                         // is automatically set to all ones, corresponding to starting all tasks in ROM0."
                         //
                         _cpu._rmr = _busData;
@@ -125,11 +125,7 @@ namespace Contralto.CPU
                         // Dispatch function to Ethernet I/O based on contents of AC0.
                         if ((_busData & 0x8000) != 0)
                         {
-                            // 
-                            // BOOT (soft-reset) operation.
-                            // Reset the CPU using the current RMR (start tasks in RAM or ROM as specified.)
-                            _cpu.SoftReset();
-
+                            
                             // Since this is a soft reset, we don't want MPC to be taken from the NEXT
                             // field at the end of the cycle, setting this flag causes the main Task
                             // implementation to skip updating _mpc at the end of this instruction.
@@ -150,7 +146,7 @@ namespace Contralto.CPU
                                     break;
 
                                 case 4:
-                                    // Orbit
+                                    // Orbit                                    
                                     _cpu._system.OrbitController.STARTF(_busData);
                                     break;
 

Contralto/CPU/Tasks/OrbitTask.cs

@@ -33,24 +33,10 @@ namespace Contralto.CPU
                 _wakeup = false;
             }
 
-            public override void OnTaskSwitch()
-            {
-                // We put ourselves back to sleep immediately once we've started running.
-                //_wakeup = false;
-            }
-
             protected override void ExecuteBlock()
             {
-                //_wakeup = false;
                 _cpu._system.OrbitController.Stop();
-            }
-
-            protected override InstructionCompletion ExecuteInstruction(MicroInstruction instruction)
-            {
-                // TODO: get rid of polling.
-                //_wakeup = _cpu._system.OrbitController.Wakeup;
-                return base.ExecuteInstruction(instruction);
-            }
+            }            
 
             protected override ushort GetBusSource(MicroInstruction instruction)
             {
@@ -80,7 +66,7 @@ namespace Contralto.CPU
                         // "When an S register is being loaded from M, the processor bus receives an
                         // undefined value rather than being set to zero."
                         _loadS = true;
-                        return 0x0;       // Technically this is an "undefined value," we're defining it as -1.
+                        return 0xffff;       // Technically this is an "undefined value," we're defining it as -1.
 
                     default:
                         throw new InvalidOperationException(String.Format("Unhandled bus source {0}", instruction.BS));

Contralto/CPU/Tasks/Task.cs

@@ -142,13 +142,14 @@ namespace Contralto.CPU
                 bool swMode = false;                
                 ushort aluData;
                 ushort nextModifier;
+                bool softReset = _softReset;
                 _loadR = false;
                 _loadS = false;
                 _rSelect = 0;                
                 _busData = 0;
                 _softReset = false;
 
-                Shifter.Reset();                
+                Shifter.Reset();
 
                 //
                 // Wait for memory state machine if a memory operation is requested by this instruction and
@@ -197,10 +198,10 @@ namespace Contralto.CPU
                             break;
 
                         case BusSource.ReadMD:
-                            _busData = _cpu._system.MemoryBus.ReadMD();                         
+                            _busData = _cpu._system.MemoryBus.ReadMD();
                             break;
 
-                        case BusSource.ReadMouse:                            
+                        case BusSource.ReadMouse:
                             // "BUS[12-15]<-MOUSE; BUS[0-13]<- -1"
                             // (Note -- BUS[0-13] appears to be a typo, and should likely be BUS[0-11]).
                             _busData = (ushort)(_cpu._system.Mouse.PollMouseBits() | 0xfff0);
@@ -533,10 +534,14 @@ namespace Contralto.CPU
                 // Select next address, using the address modifier from the last instruction.
                 // (Unless a soft reset occurred during this instruction)
                 //
-                if (!_softReset)
+                if (!softReset)
                 {
                     _mpc = (ushort)(instruction.NEXT | nextModifier);
                 }
+                else
+                {
+                    _cpu.SoftReset();
+                }
 
                 _firstInstructionAfterSwitch = false;
                 return completion;

Contralto/CPU/UCodeDisassembler.cs

@@ -250,10 +250,10 @@ namespace Contralto.CPU
             //
 
             // Load T
+            bool loadTFromALU = false;
             if (instruction.LoadT)
             {
-                // Does this operation change the source for T?
-                bool loadTFromALU = false;
+                // Does this operation change the source for T?                
                 switch (instruction.ALUF)
                 {
                     case AluFunction.Bus:
@@ -275,11 +275,18 @@ namespace Contralto.CPU
             {
                 if (string.IsNullOrEmpty(load))
                 {
+                    // T not loaded at all, L loaded from ALU
                     load = String.Format("L← {0}", operation);
                 }
+                else if (loadTFromALU)
+                {
+                    // T loaded from ALU, L loaded from ALU
+                    load = String.Format("L← {0}", load);
+                }
                 else
                 {
-                    load = String.Format("L← {0}", load);
+                    // T loaded from bus source, L loaded from ALU
+                    load = String.Format("L← {0}, {1}", operation, load);
                 }
             }
 
@@ -287,8 +294,8 @@ namespace Contralto.CPU
             if (loadR)
             {
                 load = String.Format("$R{0}← {1}", 
-                    Conversion.ToOctal((int)rSelect), 
-                    load != String.Empty ? load : operation);
+                    Conversion.ToOctal((int)rSelect),
+                    !string.IsNullOrEmpty(load) ? load : operation);
             }
 
             // Do writeback to selected S register from M
@@ -307,7 +314,18 @@ namespace Contralto.CPU
                 }
             }
 
-            if (!string.IsNullOrEmpty(load))
+            // Test for a NOP-like instruction.
+            if (!instruction.LoadL && 
+                !instruction.LoadT && 
+                !loadR && 
+                !loadS && 
+                instruction.F1 == SpecialFunction1.None &&
+                instruction.F2 == SpecialFunction2.None &&
+                instruction.ALUF == AluFunction.Bus)
+            {
+                disassembly.AppendFormat("NOP :{0}", Conversion.ToOctal(instruction.NEXT));
+            }
+            else if (!string.IsNullOrEmpty(load))
             {
                 disassembly.AppendFormat("{0}{1}{2} :{3}", 
                     f1, 
@@ -333,7 +351,8 @@ namespace Contralto.CPU
             switch(task)
             {
                 case TaskType.Emulator:
-                    return DisassembleEmulatorBusSource(instruction, out loadS);                    
+                case TaskType.Orbit:
+                    return DisassembleEmulatorBusSource(instruction, out loadS);
 
                 default:
                     loadS = false;
@@ -346,7 +365,10 @@ namespace Contralto.CPU
             switch (task)
             {
                 case TaskType.Emulator:
-                    return DisassembleEmulatorSpecialFunction1(instruction);                    
+                    return DisassembleEmulatorSpecialFunction1(instruction);
+
+                case TaskType.Orbit:
+                    return DisassembleOrbitSpecialFunction1(instruction);                    
 
                 default:
                     return String.Format("F1 {0}", Conversion.ToOctal((int)instruction.F1));
@@ -358,7 +380,10 @@ namespace Contralto.CPU
             switch (task)
             {
                 case TaskType.Emulator:
-                    return DisassembleEmulatorSpecialFunction2(instruction);                    
+                    return DisassembleEmulatorSpecialFunction2(instruction);
+
+                case TaskType.Orbit:
+                    return DisassembleOrbitSpecialFunction2(instruction);                    
 
                 default:
                     return String.Format("F2 {0}", Conversion.ToOctal((int)instruction.F2));
@@ -373,7 +398,15 @@ namespace Contralto.CPU
             {
                 case EmulatorBusSource.ReadSLocation:
                     loadS = false;
-                    return String.Format("$S{0}", Conversion.ToOctal((int)instruction.RSELECT));
+
+                    if (instruction.RSELECT == 0)
+                    {
+                        return "M";
+                    }
+                    else
+                    {
+                        return String.Format("$S{0}", Conversion.ToOctal((int)instruction.RSELECT));
+                    }
 
                 case EmulatorBusSource.LoadSLocation:
                     loadS = true;
@@ -415,7 +448,7 @@ namespace Contralto.CPU
                     return "STARTF ";
 
                 default:
-                    return String.Format("F1 {0}", Conversion.ToOctal((int)ef1));
+                    return String.Format("Emulator F1 {0}", Conversion.ToOctal((int)ef1));
             }
 
         }
@@ -448,7 +481,62 @@ namespace Contralto.CPU
                     return "IDISP ";
 
                 default:
-                    return String.Format("F2 {0}", Conversion.ToOctal((int)ef2));
+                    return String.Format("Emulator F2 {0}", Conversion.ToOctal((int)ef2));
+            }
+        }
+
+        private static string DisassembleOrbitSpecialFunction1(MicroInstruction instruction)
+        {
+            OrbitF1 of1 = (OrbitF1)instruction.F1;
+
+            switch(of1)
+            {
+                case OrbitF1.OrbitBlock:
+                    return "OrbitBlock ";
+
+                case OrbitF1.OrbitDeltaWC:
+                    return "←OrbitDeltaWC ";
+
+                case OrbitF1.OrbitDBCWidthRead:
+                    return "←OrbitDBCWidthRead ";
+
+                case OrbitF1.OrbitStatus:
+                    return "←OrbitStatus ";
+
+                default:
+                    return String.Format("Orbit F1 {0}", Conversion.ToOctal((int)of1));
+            }
+        }
+
+        private static string DisassembleOrbitSpecialFunction2(MicroInstruction instruction)
+        {
+            OrbitF2 of2 = (OrbitF2)instruction.F2;
+
+            switch (of2)
+            {
+                case OrbitF2.OrbitDBCWidthSet:
+                    return "OrbitDBCWidthSet← ";
+
+                case OrbitF2.OrbitXY:
+                    return "OrbitXY← ";
+
+                case OrbitF2.OrbitHeight:
+                    return "OrbitHeight← ";
+
+                case OrbitF2.OrbitFontData:
+                    return "OrbitFontData← ";
+
+                case OrbitF2.OrbitInk:
+                    return "OrbitInk← ";
+
+                case OrbitF2.OrbitControl:
+                    return "OrbitControl← ";
+
+                case OrbitF2.OrbitROSCommand:
+                    return "OrbitROSCommand← ";                
+
+                default:
+                    return String.Format("Orbit F2 {0}", Conversion.ToOctal((int)of2));
             }
         }
     }

Contralto/Configuration.cs

@@ -204,6 +204,21 @@ namespace Contralto
         /// </summary>
         public static string AudioDACCapturePath;
 
+        /// <summary>
+        /// Whether to enable printing via the Orbit / DoverROS interface.
+        /// </summary>
+        public static bool EnablePrinting;
+
+        /// <summary>
+        /// Path for print output.
+        /// </summary>
+        public static string PrintOutputPath;
+
+        /// <summary>
+        /// Whether to reverse the page order when printing.
+        /// </summary>
+        public static bool ReversePageOrder;
+
         /// <summary>
         /// The components to enable debug logging for.
         /// </summary>
@@ -291,6 +306,9 @@ namespace Contralto
             EnableAudioDAC = Properties.Settings.Default.EnableAudioDAC;
             EnableAudioDACCapture = Properties.Settings.Default.EnableAudioDACCapture;
             AudioDACCapturePath = Properties.Settings.Default.AudioDACCapturePath;
+            EnablePrinting = Properties.Settings.Default.EnablePrinting;
+            PrintOutputPath = Properties.Settings.Default.PrintOutputPath;
+            ReversePageOrder = Properties.Settings.Default.ReversePageOrder;
         }
 
         private static void WriteConfigurationWindows()
@@ -308,8 +326,10 @@ namespace Contralto
             Properties.Settings.Default.ThrottleSpeed = ThrottleSpeed;
             Properties.Settings.Default.EnableAudioDAC = EnableAudioDAC;
             Properties.Settings.Default.EnableAudioDACCapture = EnableAudioDACCapture;
-            Properties.Settings.Default.AudioDACCapturePath = AudioDACCapturePath;
-            Properties.Settings.Default.AudioDACCapturePath = Properties.Settings.Default.AudioDACCapturePath;
+            Properties.Settings.Default.AudioDACCapturePath = AudioDACCapturePath;            
+            Properties.Settings.Default.EnablePrinting = EnablePrinting;
+            Properties.Settings.Default.PrintOutputPath = PrintOutputPath;
+            Properties.Settings.Default.ReversePageOrder = ReversePageOrder;
             Properties.Settings.Default.Save();
         }
 

Contralto/Contralto.cfg

@@ -18,3 +18,8 @@ InterlaceDisplay = False
 BootAddress = 0
 BootFile = 0
 AlternateBootType = Ethernet
+
+# Printing options
+EnablePrinting = true
+PrintOutputPath = .
+ReversePageOrder = true

Contralto/Contralto.csproj

@@ -97,6 +97,9 @@
     <ApplicationManifest>app.manifest</ApplicationManifest>
   </PropertyGroup>
   <ItemGroup>
+    <Reference Include="itextsharp, Version=5.5.11.0, Culture=neutral, PublicKeyToken=8354ae6d2174ddca, processorArchitecture=MSIL">
+      <HintPath>..\packages\iTextSharp.5.5.11\lib\itextsharp.dll</HintPath>
+    </Reference>
     <Reference Include="NAudio, Version=1.8.0.0, Culture=neutral, processorArchitecture=MSIL">
       <HintPath>..\packages\NAudio.1.8.0\lib\net35\NAudio.dll</HintPath>
       <Private>True</Private>
@@ -127,6 +130,9 @@
     <Compile Include="IO\AudioDAC.cs" />
     <Compile Include="IO\OrbitController.cs" />
     <Compile Include="IO\OrganKeyboard.cs" />
+    <Compile Include="IO\Printing\IPageSink.cs" />
+    <Compile Include="IO\Printing\NullPageSink.cs" />
+    <Compile Include="IO\Printing\PdfPageSink.cs" />
     <Compile Include="IO\UDPEncapsulation.cs" />
     <Compile Include="IO\IPacketEncapsulation.cs" />
     <Compile Include="Properties\Resources.Designer.cs">

Contralto/IO/DiskController.cs

@@ -115,8 +115,8 @@ namespace Contralto.IO
                 if ((_kDataWrite & 0x1) != 0)
                 {
                     // Restore operation to cyl. 0:
-                    InitSeek(0);
-                }              
+                    _restore = true;
+                }
             }
         }
 
@@ -145,7 +145,7 @@ namespace Contralto.IO
                 
                 if (_sendAdr & (_kDataWrite & 0x2) != 0)
                 {
-                    _seeking = false;                                                           
+                    _seeking = false;
                 }
 
             }
@@ -244,6 +244,7 @@ namespace Contralto.IO
             _kDataWriteLatch = false;
             _sendAdr = false;
             _seeking = false;
+            _restore = false;
 
             _wdInhib = true;
             _xferOff = true;
@@ -311,7 +312,7 @@ namespace Contralto.IO
             _kDataRead = 0;
 
             // Load new sector in
-            SelectedDrive.Sector = _sector;            
+            SelectedDrive.Sector = _sector;
 
             // Only wake up if not actively seeking.
             if ((_kStat & STROBE) == 0)
@@ -417,7 +418,7 @@ namespace Contralto.IO
         public void Strobe()
         {
             //
-            // "Initiates a disk seek operation.  The KDATA register must have been loaded previously,
+            // "Initiates a disk seek [or restore] operation.  The KDATA register must have been loaded previously,
             // and the SENDADR bit of the KCOMM register previously set to 1."
             //            
 
@@ -431,7 +432,14 @@ namespace Contralto.IO
 
             Log.Write(LogComponent.DiskController, "STROBE: Seek initialized.");
 
-            InitSeek((_kDataWrite & 0x0ff8) >> 3);            
+            if (_restore)
+            {
+                InitSeek(0);
+            }
+            else
+            {
+                InitSeek((_kDataWrite & 0x0ff8) >> 3);
+            }
         }
 
         private void InitSeek(int destCylinder)
@@ -636,7 +644,8 @@ namespace Contralto.IO
             {
                 // clear Seek bit
                 _kStat &= (ushort)~STROBE;
-                _seeking = false;                
+                _seeking = false;
+                _restore = false;
 
                 Log.Write(LogComponent.DiskController, "Seek to {0} completed.", SelectedDrive.Cylinder);
             }
@@ -704,6 +713,7 @@ namespace Contralto.IO
         private ulong _seekDuration;
         private Event _seekEvent;
         private bool _seeking;
+        private bool _restore;
 
         // Selected disk
         private int _disk;

Contralto/IO/DoverROS.cs

@@ -1,11 +1,24 @@
-using Contralto.Logging;
+/*  
+    This file is part of ContrAlto.
+
+    ContrAlto is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Affero General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ContrAlto is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Affero General Public License for more details.
+
+    You should have received a copy of the GNU Affero General Public License
+    along with ContrAlto.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+
+using Contralto.IO.Printing;
+using Contralto.Logging;
 using System;
-using System.Collections.Generic;
-using System.Drawing;
-using System.Drawing.Imaging;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
 
 namespace Contralto.IO
 {
@@ -22,18 +35,28 @@ namespace Contralto.IO
     }
 
     /// <summary>
-    /// Encapsulates the logic for both the ROS and the printer portions of the
-    /// print pipeline.
+    /// Encapsulates the logic for both the ROS (Raster Output Scanner) hardware and
+    /// the Dover print engine.
+    /// 
+    /// These two should probably be separated out in the event that we want to support
+    /// other kinds of printers.
+    /// 
+    /// The Dover print engine support is currently very hand-wavy as the documentation
+    /// isn't extremely specific on some details and we're emulating a mechanical construct
+    /// moving papers past sensors, etc.  It mostly works but it has some rough edges.
+    /// In particular the "Cold Start" mechanic is not well understood.  Many parameters
+    /// are currently ignored (some for good reason; we don't need to emulate the actual
+    /// laser scanning and polygon rotation in order to create a bitmap, for example) but
+    /// some of them might be put to good use.
+    /// 
+    /// None of the diagnostic switches or options are implemented.
     /// </summary>
     public class DoverROS
     {
         public DoverROS(AltoSystem system)
         {
-            _system = system;
-
-            _cs5Event = new Event(0, null, ColdStartCallback);
-            _innerLoopEvent = new Event(0, null, InnerLoopCallback);
-            _pageBuffer = new Bitmap(4096, 4096, PixelFormat.Format1bppIndexed);
+            _system = system;            
+            _printEngineEvent = new Event(0, null, PrintEngineCallback);
 
             Reset();
         }
@@ -54,9 +77,8 @@ namespace Contralto.IO
 
             _packetsOK = true;
 
-            _state = PrintState.ColdStart;
-            _innerLoopState = InnerLoopState.Idle;
-            _coldStartState = ColdStartState.SendVideoLow;
+            _state = PrintState.Idle;
+            _runoutCount = 0;
         }
 
         public void RecvCommand(ushort commandWord)
@@ -83,27 +105,40 @@ namespace Contralto.IO
                     _extendVideo = (argument & 0x20) != 0;
                     _motorScale = (argument & 0x1c0) >> 6;
                     _bitScale = (argument & 0xe00) >> 9;
+
+                    Log.Write(LogComponent.DoverROS, "TestMode {0} CommandBeamOn {1} CommandLocal {2} TestPageSync {3} ExtendVideo {4} MotorScale {5} BitScale {6}",
+                        _testMode,
+                        _commandBeamOn,
+                        _commandLocal,
+                        _testPageSync,
+                        _extendVideo,
+                        _motorScale,
+                        _bitScale);
                     break;
 
                 case AdapterCommand.SetBitClockRegister:
                     _bitClock = argument;
+                    Log.Write(LogComponent.DoverROS, "BitClock set to {0}", argument);
                     break;
 
                 case AdapterCommand.SetMotorSpeedRegister:
                     _motorSpeed = argument;
+                    Log.Write(LogComponent.DoverROS, "MotorSpeed set to {0}", argument);
                     break;
 
                 case AdapterCommand.SetLineSyncDelayRegister:
                     _lineSyncDelay = argument;
+                    Log.Write(LogComponent.DoverROS, "LineSyncDelay set to {0}", argument);
                     break;
 
                 case AdapterCommand.SetPageSyncDelayRegister:
                     _pageSyncDelay = argument;
+                    Log.Write(LogComponent.DoverROS, "PageSyncDelay set to {0}", argument);
                     break;
 
                 case AdapterCommand.ExternalCommand1:
 
-                    bool lastPrintRequest = (_externalCommand1 & 0x1) != 0;
+                    bool lastPrintRequest = (_externalCommand1 & 0x1) == 0;
 
                     _externalCommand1 = argument;
 
@@ -113,7 +148,7 @@ namespace Contralto.IO
                     // sheets.
                     //
                     Log.Write(LogComponent.DoverROS, "ExternalCommand1 written {0}", argument);
-                    if (lastPrintRequest && (_externalCommand1 & 0x1) == 0)
+                    if (lastPrintRequest && (_externalCommand1 & 0x1) != 0)
                     {
                         PrintRequest();
                     }
@@ -121,6 +156,7 @@ namespace Contralto.IO
 
                 case AdapterCommand.ExternalCommand2:
                     _videoGate = argument;
+                    Log.Write(LogComponent.DoverROS, "VideoGate set to {0}", argument);
                     break;
 
                 default:
@@ -164,8 +200,6 @@ namespace Contralto.IO
                     value |= (_local ? 0x2000 : 0);
                     value |= (_beamEnable ? 0x1000 : 0);
                     value |= (_statusBeamOn ? 0x0800 : 0);
-
-                    //Log.Write(LogComponent.DoverROS, "ROS word 0 bits 0-15: {0}", Conversion.ToOctal(value));
                     break;
 
                 case 1:
@@ -255,6 +289,24 @@ namespace Contralto.IO
                     //
                     value |= (_lineCount << 12);
                     value |= _videoGate;
+
+                    //
+                    // LineCount is not well documented anywhere in the hardware documentation
+                    // available.  It is related to the motion of the laser as it sweeps across
+                    // the page.  The source code for Spruce (SprucePrinDover.bcpl)
+                    // has this to say:
+                    // "A check, designed chiefly for Dover, verifies that the laser is on and the polygon is
+                    //  scanning (SOS/EOS are seeing things), by making sure that the low four bits of the line
+                    //  count (indicated in status word) are  changing. The code reads the line count, waits
+                    //  approximately the time needed for four scan lines (generous margin), then reads the
+                    //  count again, reporting a problem if the values are equal."
+                    //
+
+                    //
+                    // Indeed, if this value does not increment, Spruce fails with a
+                    // "Laser appears to be off" error.
+                    // We fudge this here.
+                    _lineCount++;
                     break;
 
                 case 8:
@@ -270,9 +322,7 @@ namespace Contralto.IO
                     // 8 - LS4 (adequate paper in tray)
                     // 11 - LaserOn
                     // 13 - ReadyTemp
-                    value |= 0x214;
-
-                    Log.Write(LogComponent.DoverROS, "Dover bits 0-15: {0}", Conversion.ToOctal(value));
+                    value |= 0x0094;
                     break;
 
                 case 9:
@@ -284,8 +334,7 @@ namespace Contralto.IO
                     // These are:
                     // 5 - ACMonitor
                     // 13 - LS24 & LS31
-
-                    value |= 0x2004;
+                    value |= 0x0404;
 
                     Log.Write(LogComponent.DoverROS, "Dover bits 16-31: {0}", Conversion.ToOctal(value));
                     break;
@@ -302,6 +351,7 @@ namespace Contralto.IO
 
                 default:
                     Log.Write(LogComponent.DoverROS, "Unhandled ROS status word {0}", wordNumber);
+                    value = 0xffff;
                     break;
             }
 
@@ -310,301 +360,388 @@ namespace Contralto.IO
 
         private void PrintRequest()
         {
-            switch(_state)
+            switch (_state)
             {
-                case PrintState.ColdStart:
-
+                case PrintState.Idle:
                     if (!_printMode)
                     {
+                        _state = PrintState.ColdStart;
                         _printMode = true;
-                        _sendVideo = false;
+                        _sendVideo = true;
+                        _keepGoing = false;
+                        _runoutCount = 0;
 
-                        // Queue a 250ms event to fire CS-5(0).
-                        // and 990ms item to cancel printing if a second
-                        // print-request isn't received.
-                        _innerLoopState = InnerLoopState.CS5;
-                        _innerLoopEvent.TimestampNsec = (ulong)(120 * Conversion.MsecToNsec);
-                        _system.Scheduler.Schedule(_innerLoopEvent);
+                        ClearPageRaster();
 
-                        Log.Write(LogComponent.DoverROS, "Cold Start initialized at {0}ms -- CS-5(0) in 250ms.", _system.Scheduler.CurrentTimeNsec * Conversion.NsecToMsec);
+                        //
+                        // Calculate a few things based on ROS parameters
+                        //
+                        // PageSyncDelay is (4096-n/i) where n is the number of
+                        // scan-lines to pass up after receiving PageSync from the engine
+                        // before starting SendVideo.  i is 1 for Dover II, and 4 for older
+                        // ones.
+                        // We assume a Dover I here.
+                        _sendVideoStartScanline = 4 * (4096 - _pageSyncDelay);
+
+                        //
+                        // VideoGate is (4096-n/4) where n is the number of scan-lines to
+                        // pass up after SendVideo starts before stopping SendVideo.
+                        _sendVideoEndScanline = 4 * (4096 - _videoGate) + _sendVideoStartScanline;
+
+                        Log.Write(LogComponent.DoverROS, "SendVideo start {0}, end {1}",
+                            _sendVideoStartScanline,
+                            _sendVideoEndScanline);
+
+                        //
+                        // Start printing engine running.
+                        //
+                        _printEngineEvent.TimestampNsec = _printEngineTimestepInterval;
+                        _system.Scheduler.Schedule(_printEngineEvent);
+                        _printEngineTimestep = -375;        // Start 250ms before the first CS-5
+
+                        //
+                        // Start output
+                        //
+                        InitializePrintOutput();                        
+
+                        Log.Write(LogComponent.DoverROS, "Cold Start initialized.  Engine started.");
                     }
                     else
                     {
-                        Log.Write(LogComponent.DoverROS, "PrintRequest received in cold start at {0}ms.", _system.Scheduler.CurrentTimeNsec * Conversion.NsecToMsec);
-                        _keepGoing = true;
+                        Log.Write(LogComponent.DoverROS, "Unexpected PrintRequest with PrintMode active during Idle.");
                     }
+
+                    break;
+
+                case PrintState.ColdStart:
+                    Log.Write(LogComponent.DoverROS, "PrintRequest received in cold start.");
+                    _keepGoing = true;
                     break;
 
                 case PrintState.InnerLoop:
                     if (!_printMode)
                     {
                         // PrintRequest too late.
-                        Log.Write(LogComponent.DoverROS, "PrintRequest too late.  Ignoring.");
+                        Log.Write(LogComponent.DoverROS, "PrintRequest too late during Inner Loop.  Ignoring.");
                     }
                     else
                     {
-                        if (_innerLoopState != InnerLoopState.Idle)
-                        {
-                            Log.Write(LogComponent.DoverROS, "PrintRequest received in inner loop.");
-                            _keepGoing = true;
-                        }
-                        else
-                        {
-                            // 
-                            // Currently idle:  Kick off the first round of the inner loop.
-                            // Queue a PageSyncDelay (250ms) event to pulse SendVideo
-                            // after the pulse, gather video raster from Orbit
-                            //
-                            Log.Write(LogComponent.DoverROS, "PrintRequest received, starting inner loop.");
-                            _innerLoopState = InnerLoopState.CS5;
-                            _innerLoopEvent.TimestampNsec = 120 * Conversion.MsecToNsec;
-                            _system.Scheduler.Schedule(_innerLoopEvent);
-                        }
+                        Log.Write(LogComponent.DoverROS, "PrintRequest during inner loop.  Continuing.");
+                        _keepGoing = true;
                     }
                     break;
 
                 case PrintState.Runout:
-                    Log.Write(LogComponent.DoverROS, "Runout.");
-                    break;
-
-            }
-
-        }
-
-        private void InnerLoopCallback(ulong timestampNsec, ulong delta, object context)
-        {
-            switch(_innerLoopState)
-            {
-                case InnerLoopState.CS5:
-                    _countH = false;
-                    _sendVideo = false;
-
-                    // Keep SendVideo low for 125ms
-                    _innerLoopState = InnerLoopState.SendVideo;
-                    _innerLoopEvent.TimestampNsec = 125 * Conversion.MsecToNsec;
-                    _system.Scheduler.Schedule(_innerLoopEvent);
-
-                    Log.Write(LogComponent.DoverROS, "Inner loop: CS5");
-                    break;
-
-                case InnerLoopState.SendVideo:
-                    _sendVideo = true;
-
-                    _innerLoopState = InnerLoopState.ReadBands;
-                    _readBands = 0;
-
-                    // time for one band of 16 scanlines to be read (approx.)
-                    _innerLoopEvent.TimestampNsec = (ulong)(0.2 * Conversion.MsecToNsec);
-                    _system.Scheduler.Schedule(_innerLoopEvent);
-
-                    Log.Write(LogComponent.DoverROS, "Inner loop: SendVideo");
-                    break;
-
-                case InnerLoopState.ReadBands:
-                    // Assume 3000 scanlines for an 8.5" sheet of paper at 350dpi.
-                    // If the Orbit is allowing us to read the output buffer then
-                    // we will do so, otherwise we emit nothing.
-                    if (_readBands > 3000)
+                    if (!_printMode)
                     {
-                        if (_state == PrintState.ColdStart)
-                        {
-                            _innerLoopState = InnerLoopState.ColdStartEnd;
-                        }
-                        else
-                        {
-                            _innerLoopState = InnerLoopState.CountH;
-                        }
+                        // PrintRequest too late.
+                        Log.Write(LogComponent.DoverROS, "PrintRequest too late during Runout.  Ignoring.");
                     }
                     else
                     {
-                        if (_system.OrbitController.SLOTTAKE)
+                        Log.Write(LogComponent.DoverROS, "PrintRequest during Runout.  Moving to Inner Loop.");
+                        _state = PrintState.InnerLoop;                        
+                        _keepGoing = true;
+                        _runoutCount = 0;
+                    }
+                    break;
+            }
+        }
+
+        private void InitializePrintOutput()
+        {
+            //
+            // Select the appropriate output based on the configuration.
+            // For now it's either PDF or nothing.
+            //
+            if (Configuration.EnablePrinting)
+            {
+                _pageOutput = new PdfPageSink();
+            }
+            else
+            {
+                _pageOutput = new NullPageSink();
+            }
+
+            _pageOutput.StartDoc();
+        }
+
+        /// <summary>
+        /// This is invoked for every scanline that passes under the virtual print path.
+        /// At each scanline flags are updated and raster data is pulled from the Orbit and
+        /// copied to the page as necessary.
+        /// </summary>
+        /// <param name="timestampNsec"></param>
+        /// <param name="delta"></param>
+        /// <param name="context"></param>
+        private void PrintEngineCallback(ulong timestampNsec, ulong delta, object context)
+        {
+            Log.Write(LogComponent.DoverROS, "Scanline {0} (sendvideo {1})", _printEngineTimestep, _sendVideo);
+            switch (_state)
+            {
+                case PrintState.ColdStart:
+                    {
+                        // Go through the motions but don't rasterize anything
+                        //
+                        // The Cold-start loop starts 250ms before the first CS-5 signal.                        
+                        if (_printEngineTimestep >= 0 && _printEngineTimestep < _sendVideoStartScanline)
                         {
-                            // Read in 16 scanlines of data -- this is 256x16 words
-                            for (int y = 0; y < 16; y++)
+                            _sendVideo = false;
+                        }
+                        else
+                        {
+                            _sendVideo = true;
+                        }
+
+
+                        if (_printEngineTimestep >= 0 && 
+                            _printEngineTimestep < _sendVideoEndScanline)
+                        {
+                            // Pull rasters one scanline at a time out of Orbit,
+                            // since we're in cold-start, these are discarded.
+                            if (_system.OrbitController.SLOTTAKE)
                             {
+                                // Read in one scanline of data -- this is 256 words
                                 for (int x = 0; x < 256 - _system.OrbitController.FA; x++)
                                 {
                                     ushort word = _system.OrbitController.GetOutputDataROS();
 
-                                    _pageData[(_readBands + y) * 512 + x * 2] = (byte)(word & 0xff);
-                                    _pageData[(_readBands + y) * 512 + x * 2 + 1] = (byte)(word >> 8);
-
-                                 
+                                    // The assumption is that during this phase the Alto will just
+                                    // be sending zeroes, log if this assumption does not hold...
+                                    //
+                                    if (word != 0)
+                                    {
+                                        Log.Write(LogComponent.DoverROS, "Read non-zero orbit data during cold-start {0}", Conversion.ToOctal(word));
+                                    }
                                 }
+
+                                Log.Write(LogComponent.DoverROS, "Read cold-start band {0}", _readBands);
+                            }
+                            else
+                            {
+                                // Nothing right now
+                                Log.Write(LogComponent.DoverROS, "No bands available from Orbit.");
                             }
 
-                            Log.Write(LogComponent.DoverROS, "Read bands {0}", _readBands);
+                            _readBands++;
+                        }
+
+                        if (_printEngineTimestep >= 3136)
+                        {
+                            // After appx. 896ms (3136 scanlines) the first Count-H is raised.
+                            _countH = true;
+                        }
+
+                        _printEngineTimestep++;
+
+                        if (_printEngineTimestep >= 3500)
+                        {
+                            // End of cold-start "page."
+                            _readBands = 0;
+                            _printEngineTimestep = 0;
+                            _countH = false;
+                            ClearPageRaster();
+
+                            if (_keepGoing)
+                            {
+                                // 
+                                // We got a PrintRequest during ColdStart, so we'll continue to the next page.
+                                //
+                                Log.Write(LogComponent.DoverROS, "End of Cold Start, switching to Inner Loop.");
+                                _state = PrintState.InnerLoop;
+                            }
+                            else
+                            {
+                                //
+                                // No PrintRequest, we will switch to Runout and begin shutting down.
+                                //
+                                Log.Write(LogComponent.DoverROS, "End of Cold Start, switching to Runout.");
+                                _state = PrintState.Runout;
+                            }
+
+                            _keepGoing = false;
+                        }
+
+                        _printEngineEvent.TimestampNsec = _printEngineTimestepInterval;
+                        _system.Scheduler.Schedule(_printEngineEvent);
+                    }
+                    break;
+
+                case PrintState.InnerLoop:
+                    {
+                        //
+                        // Inner loop starts with CS-5 (timestep 0).
+                        // After which there is a delay (PageSyncDelay) before
+                        // SendVideo goes high and we can start reading raster data.
+                        if (_printEngineTimestep < _sendVideoStartScanline)
+                        {
+                            _sendVideo = false;
                         }
                         else
                         {
-                            // Nothing right now
-                            Log.Write(LogComponent.DoverROS, "No bands available from Orbit.");
+                            _sendVideo = true;
                         }
 
-                        _readBands += 16;
-
-                        if (_readBands > 2500 && !_countH)
+                        if (_printEngineTimestep >= 0 && 
+                            _printEngineTimestep < _sendVideoEndScanline)
                         {
+                            // Video gate : pull rasters one scanline at a time out of Orbit.
+                            if (_system.OrbitController.SLOTTAKE)
+                            {
+                                // Read in one scanline's worth of data
+                                int scanlineWordCount = 256 - _system.OrbitController.FA;
+                                for (int x = 0; x < scanlineWordCount; x++)
+                                {
+                                    ushort word = _system.OrbitController.GetOutputDataROS();
+                                    
+                                    int pageDataIndex = _readBands * scanlineWordCount * 2 + x * 2;
+                                    _pageData[pageDataIndex] = (byte)(~word >> 8);
+                                    _pageData[pageDataIndex + 1] = (byte)(~word & 0xff);
+                                }
+
+                                Log.Write(LogComponent.DoverROS, "Read band {0}", _readBands);
+                            }
+                            else
+                            {
+                                // Nothing right now
+                                Log.Write(LogComponent.DoverROS, "No bands available from Orbit.");
+                            }
+
+                            _readBands++;
+                        }
+
+                        if (_printEngineTimestep >= 3136)
+                        {
+                            // After appx. 896ms (3136 scanlines) Count-H is raised.
                             _countH = true;
-                            Log.Write(LogComponent.DoverROS, "Enabling CountH");
+                        }
+
+                        _printEngineTimestep++;
+
+                        if (_printEngineTimestep >= 3500)
+                        {
+                            //
+                            // Send page rasters to the print output.
+                            //
+                            _pageOutput.AddPage(_pageData, _readBands, (256 - _system.OrbitController.FA) * 16);
+
+                            ClearPageRaster();
+
+                            // End of page.
+                            _countH = false;
+                            _readBands = 0;
+                            _printEngineTimestep = 0;
+
+                            if (_keepGoing)
+                            {
+                                //
+                                // A PrintRequest was recieved during the Inner Loop, so we'll keep going to the next page.
+                                Log.Write(LogComponent.DoverROS, "End of Page, continuing in Inner Loop.");
+                                _state = PrintState.InnerLoop;
+                            }
+                            else
+                            {
+                                Log.Write(LogComponent.DoverROS, "End of Page, switching to Runout.");
+                                _state = PrintState.Runout;
+                            }
+
+                            _keepGoing = false;
+                        }
+
+                        _printEngineEvent.TimestampNsec = _printEngineTimestepInterval;
+                        _system.Scheduler.Schedule(_printEngineEvent);
+
+                    }
+                    break;
+
+                case PrintState.Runout:
+                    {
+                        //
+                        // SendVideo still gets toggled during Runout.  CountH is
+                        // toggled by paper moving past a sensor, which does not happen
+                        // during runout.
+                        //
+                        if (_printEngineTimestep < _sendVideoStartScanline)
+                        {
+                            _sendVideo = false;
+                        }
+                        else
+                        {
+                            _sendVideo = true;
+                        }
+
+                        _printEngineTimestep++;
+
+                        if (_printEngineTimestep >= 3500)
+                        {
+
+                            // End of runout cycle.
+                            _countH = false;
+                            _printEngineTimestep = 0;
+
+                            if (_keepGoing)
+                            {
+                                Log.Write(LogComponent.DoverROS, "End of Runout cycle {0}, continuing in Inner Loop.", _runoutCount);
+                                _state = PrintState.InnerLoop;
+                            }
+                            else
+                            {
+                                Log.Write(LogComponent.DoverROS, "End of Runout cycle {0}.", _runoutCount);
+                                _state = PrintState.Runout;
+                            }
+
+                            _keepGoing = false;
+
+                            _runoutCount++;
+                        }
+
+                        if (_runoutCount > 7)
+                        {
+                            // Just shut off.
+                            _state = PrintState.Idle;
+                            _printMode = false;
+                            _countH = false;
+                            _sendVideo = false;
+
+                            //
+                            // Finish the output.
+                            //
+                            _pageOutput.EndDoc();
+
+                            Log.Write(LogComponent.DoverROS, "Runout: shutting down, switching to Idle state.  Output completed.");
+                        }
+                        else
+                        {
+                            //
+                            // Go around for another Runout cycle.
+                            _printEngineEvent.TimestampNsec = _printEngineTimestepInterval;
+                            _system.Scheduler.Schedule(_printEngineEvent);
                         }
                     }
-
-                    // time for one band of 16 scanlines to be read (approx.)
-                    _innerLoopEvent.TimestampNsec = (ulong)(0.2 * Conversion.MsecToNsec);
-                    _system.Scheduler.Schedule(_innerLoopEvent);
-                    break;
-
-                case InnerLoopState.CountH:
-                    _countH = false;
-
-                    if (_keepGoing)
-                    {
-                        // PrintRequest during ColdStart -- move to Inner loop
-                        _keepGoing = false;
-                        _state = PrintState.InnerLoop;
-                        _innerLoopState = InnerLoopState.CS5;
-                        Log.Write(LogComponent.DoverROS, "PrintRequest during ColdStart -- moving to inner loop.");
-                    }
-                    else
-                    {
-                        _innerLoopState = InnerLoopState.Idle;
-                        Log.Write(LogComponent.DoverROS, "No PrintRequest during ColdStart -- idling.");
-                    }
-
-                   
-                    break;
-
-                case InnerLoopState.ColdStartEnd:
-                    if (_keepGoing)
-                    {
-                        //
-                        // Got a PrintRequest during cold start, start the inner loop.
-                        //
-                        _keepGoing = false;
-                        _state = PrintState.InnerLoop;
-                        _innerLoopState = InnerLoopState.CS5;
-                        Log.Write(LogComponent.DoverROS, "Inner loop: CountH -- continuing");
-                    }
-                    else
-                    {
-                        //
-                        // No Print Request; idle and shut down.
-                        //
-                        _innerLoopState = InnerLoopState.Idle;
-                        Log.Write(LogComponent.DoverROS, "Inner loop: CountH -- idling");
-                    }
-
-                    // Debug: Put picture in image
-                    /*
-                    BitmapData data = _pageBuffer.LockBits(_pageRect, ImageLockMode.WriteOnly, PixelFormat.Format1bppIndexed);
-
-                    IntPtr ptr = data.Scan0;
-                    System.Runtime.InteropServices.Marshal.Copy(_pageData, 0, ptr, _pageData.Length);
-
-                    _pageBuffer.UnlockBits(data);
-
-                    EncoderParameters p = new EncoderParameters(1);
-                    p.Param[0] = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, 100L);
-
-                    _pageBuffer.Save(String.Format("c:\\temp\\raster{0}.png", _rasterNum++), GetEncoderForFormat(ImageFormat.Png), p);
-                    */
-
-                    _innerLoopEvent.TimestampNsec = (ulong)(150 * Conversion.MsecToNsec);
-                    _system.Scheduler.Schedule(_innerLoopEvent);
-
-                    _innerLoopEvent.TimestampNsec = (ulong)(150 * Conversion.MsecToNsec);
-                    _system.Scheduler.Schedule(_innerLoopEvent);
-                    break;
-
-                case InnerLoopState.Idle:
-                    _countH = false;
-                    _sendVideo = false;
-                    _printMode = false;
-                    _state = PrintState.ColdStart;
-                    Log.Write(LogComponent.DoverROS, "Inner loop: Idle");
                     break;
             }
         }
 
-        private void ColdStartCallback(ulong timestampNsec, ulong delta, object context)
+        private void ClearPageRaster()
         {
-            switch (_coldStartState)
+            //
+            // reset to white
+            //
+            for(int i=0;i<_pageData.Length;i++)
             {
-                case ColdStartState.SendVideoLow:
-                    _sendVideo = false;
-
-                    // Keep SendVideo low for 125ms
-                    _coldStartState = ColdStartState.SendVideoHigh;
-                    _cs5Event.TimestampNsec = 125 * Conversion.MsecToNsec;
-                    _system.Scheduler.Schedule(_cs5Event);
-
-                    Log.Write(LogComponent.DoverROS, "Cold start: toggle SendVideo low");
-                    break;
-
-                case ColdStartState.SendVideoHigh:
-                    _sendVideo = true;
-
-                    _coldStartState = ColdStartState.Timeout;
-                    _cs5Event.TimestampNsec = 800 * Conversion.MsecToNsec;
-                    _system.Scheduler.Schedule(_cs5Event);
-
-                    Log.Write(LogComponent.DoverROS, "Cold start: toggle SendVideo high");
-                    break;
-
-                case ColdStartState.Timeout:
-                    if (_state == PrintState.ColdStart)
-                    {
-                        // Never moved from ColdStart, Alto never sent another PageRequest.
-                        Log.Write(LogComponent.DoverROS, "Cold start timeout. Aborting.");
-                        _sendVideo = false;
-                        _printMode = false;
-                    }
-                    break;
+                _pageData[i] = 0xff;
             }
         }
 
-        private ImageCodecInfo GetEncoderForFormat(ImageFormat format)
-        {
-            ImageCodecInfo[] codecs = ImageCodecInfo.GetImageDecoders();
-
-            foreach (ImageCodecInfo codec in codecs)
-            {
-                if (codec.FormatID == format.Guid)
-                {
-                    return codec;
-                }
-            }
-            return null;
-        }
-
         private enum PrintState
         {
-            ColdStart = 0,
+            Idle = 0,
+            ColdStart,
             InnerLoop,
             Runout
         }
 
-        private enum ColdStartState
-        {
-            SendVideoLow,
-            SendVideoHigh,
-            Timeout
-        }
-
-        private enum InnerLoopState
-        {
-            Idle = 0,
-            CS5,
-            SendVideo,
-            ReadBands,
-            CountH,
-            ColdStartEnd,
-        }
-
         private PrintState _state;
-        private InnerLoopState _innerLoopState;
-        private ColdStartState _coldStartState;
 
         private bool _keepGoing;
         private int _readBands;
@@ -653,8 +790,8 @@ namespace Contralto.IO
         private bool _switch4;
 
         // ID and serial number
-        private ushort _id;
-        private ushort _serialNumber;
+        private ushort _id = 0;
+        private ushort _serialNumber = 0;
 
         //
         // Dover specific status that we care to report.
@@ -671,15 +808,35 @@ namespace Contralto.IO
         //
         private bool _countH;
 
+        /// <summary>
+        /// Number of passes through the Runout state.
+        /// </summary>
+        private int _runoutCount;
+
 
         // Events to drive the print state machine
-        //
-        private Event _cs5Event;        
-        private Event _innerLoopEvent;
+        //          
+        private Event _printEngineEvent;
 
-        private byte[] _pageData = new byte[4096 * 512];
-        private Rectangle _pageRect = new Rectangle(0, 0, 4096, 4096);
-        private Bitmap _pageBuffer;
+        private int _printEngineTimestep;
+        private int _sendVideoStartScanline;
+        private int _sendVideoEndScanline;
+
+
+        /// <summary>
+        /// The timeslice for a single engine step (one scanline).
+        /// There are (in theory) 2975 scanlines per 8.5" page (at 350dpi) which moves
+        /// through the engine in 850ms.  
+        /// 
+        /// The cycle time for an entire page is 1000ms, which we pretend
+        /// is 3500 scanline times.
+        /// 
+        /// </summary>
+        private ulong _printEngineTimestepInterval = (ulong)((1000.0 / 3500.0) * Conversion.MsecToNsec);
+
+        private byte[] _pageData = new byte[3500 * 512];
         private int _rasterNum;
+
+        private IPageSink _pageOutput;
     }
 }

Contralto/IO/OrbitController.cs

@@ -1,9 +1,21 @@
-using Contralto.Logging;
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
+/*  
+    This file is part of ContrAlto.
+
+    ContrAlto is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Affero General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ContrAlto is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Affero General Public License for more details.
+
+    You should have received a copy of the GNU Affero General Public License
+    along with ContrAlto.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+using Contralto.Logging;
 
 namespace Contralto.IO
 {
@@ -17,12 +29,10 @@ namespace Contralto.IO
         public OrbitController(AltoSystem system)
         {
             _system = system;
-
             _ros = new DoverROS(system);
-
             _refreshEvent = new Event(_refreshInterval, null, RefreshCallback);           
 
-            Reset();
+            Reset();            
         }
 
         public bool RefreshTimerExpired
@@ -48,10 +58,7 @@ namespace Contralto.IO
         public void Reset()
         {
             //
-            // A Reset performs at least the following functions:
-            // FA <- 0, SLOTTAKE <- 0, band buffer A is assigned
-            // to the image buffer, the status and control dialogs
-            // with the adapter are reset.
+            // Reset to power-up (or reboot) defaults.
             //
             _fa = 0;
             _slottake = false;
@@ -70,10 +77,46 @@ namespace Contralto.IO
             _goAway = false;
             _behind = false;
 
+            _stableROS = true;
+            _badROS = false;            
+
+            Log.Write(LogComponent.Orbit, "Orbit system reset.");
+            UpdateWakeup();
+        }
+
+        private void OrbitReset()
+        {
+            //
+            // A Reset performs at least the following functions:
+            // FA <- 0, SLOTTAKE <- 0, band buffer A is assigned
+            // to the image buffer, the status and control dialogs
+            // with the adapter are reset.
+            //
+            _fa = 0;
+            _slottake = false;
+
+            _image = _a;
+            _output = _b;
+            _incon = false;
+
+            _outputY = 0;
+            _outputX = 0;
+            
+            // Cleared "by reseting [sic] Orbit"
+            _iacs = false;
+
+            // Cleared by a buffer switch or an Orbit reset
+            _goAway = false;
+
+            _refresh = false;
+
+            _behind = false;
+
             _stableROS = true;
             _badROS = false;
 
-            Log.Write(LogComponent.Orbit, "Orbit reset.");            
+            Log.Write(LogComponent.Orbit, "Orbit reset.");
+            UpdateWakeup();
         }
 
         public bool Wakeup
@@ -86,17 +129,36 @@ namespace Contralto.IO
             }
         }
 
+        private void UpdateWakeup()
+        {
+            if (_system.CPU == null)
+                return;
+
+            if (Wakeup)
+            {
+                _system.CPU.WakeupTask(CPU.TaskType.Orbit);
+                Log.Write(LogComponent.Orbit, "Orbit wakeup.");
+            }
+            else
+            {
+                _system.CPU.BlockTask(CPU.TaskType.Orbit);
+                Log.Write(LogComponent.Orbit, "Orbit block.");
+            }
+        }
+
         public void STARTF(ushort value)
         {
             // Kick off the refresh timer if it's not already pending
 
             // Wake up task, etc.
             _run = true;
-            _system.CPU.WakeupTask(CPU.TaskType.Orbit);
 
             // "IACS is cleared by StartIO(4)"
             _iacs = false;
 
+            // per microcode, GOAWAY is cleared
+            _goAway = false;
+
             if (!_refreshRunning)
             {
                 _refreshRunning = true;
@@ -105,15 +167,16 @@ namespace Contralto.IO
             }
 
             Log.Write(LogComponent.Orbit, "Orbit started.");
+
+            UpdateWakeup();
         }
 
         public void Stop()
         {
             _run = false;
 
-            _system.CPU.BlockTask(CPU.TaskType.Orbit);
-
-            //Log.Write(LogComponent.Orbit, "Orbit blocked.");
+            Log.Write(LogComponent.Orbit, "Orbit stopped.");
+            UpdateWakeup();
         }
 
         public void Control(ushort value)
@@ -133,7 +196,7 @@ namespace Contralto.IO
             //
             if ((value & 0x1) != 0)
             {
-                Reset();
+                OrbitReset();
             }
 
             //
@@ -156,11 +219,9 @@ namespace Contralto.IO
             {
                 _fa = auxControl;
 
-                _outputY = _fa;
-
                 // "The setting of FA provided by the Alto is examined only when
                 // Orbit reads out the last 16 bits of a scanline..."
-                // (So we *should* leave _outputY alone here).
+                // (So we should leave _outputY alone here).
             }
             else
             {
@@ -173,7 +234,6 @@ namespace Contralto.IO
             if ((value & 0x8) != 0)
             {
                 _goAway = true;
-                _system.CPU.BlockTask(CPU.TaskType.Orbit);
             }
 
             //
@@ -195,11 +255,13 @@ namespace Contralto.IO
             if ((value & 0xc0) == 0xc0)
             {
                 _slottake = true;
-            }
+            }            
 
             Log.Write(LogComponent.Orbit,
                "Set Control: aux {0}, reset {1} refresh {2} which {3} goaway {4} behind {5} slottake {6}",
                     auxControl, (value & 0x1) != 0, (value & 0x2) != 0, (value & 0x4) != 0, _goAway, _behind, _slottake);
+
+            UpdateWakeup();
         }
 
         public void SetHeight(ushort value)
@@ -258,10 +320,10 @@ namespace Contralto.IO
             _cx = _x;
             _cy = _y;
 
-            _scanlines = (_x + (_width + 1) < 16) ? (_width + 1): 16 - _x;
-
             Log.Write(LogComponent.Orbit,
                "Set DBCWidth: DeltaBC {0}, Width {1}", _deltaBC, _width);
+
+            UpdateWakeup();
         }
 
         public void WriteFontData(ushort value)
@@ -277,10 +339,13 @@ namespace Contralto.IO
             if (!_iacs)
             {
                 Log.Write(LogType.Error, 
-                    LogComponent.Orbit, "Unxpected OrbitFontData while IACS false.");
+                    LogComponent.Orbit, "Unexpected OrbitFontData while IACS false.");
                 return;
             }
 
+            Log.Write(LogComponent.Orbit,
+                "Font Data: {0}", Conversion.ToOctal(value));
+
             //
             // We insert the word one bit at a time; this is more costly
             // computationally but it's a ton simpler than dealing with word
@@ -290,15 +355,16 @@ namespace Contralto.IO
             if (_firstWord)
             {
                 startBit = 15 - _deltaBC;
+                _firstWord = false;
             }
-
+            
             for(int i = startBit; i >=0 ;i--)
             {
                 int bitValue = (value & (0x1 << i)) == 0 ? 0 : 1;
 
                 if (bitValue != 0 && _cy < 4096)        // clip to end of band
                 {
-                    SetImageRasterBit(_cx, _cy, bitValue);
+                    SetImageRasterBit(_cx, _cy);
                 }
 
                 _cy++;
@@ -316,15 +382,24 @@ namespace Contralto.IO
                     {
                         _iacs = false;
 
-                        Log.Write(LogComponent.DoverROS, "Image band completed.");
+                        //
+                        // A height of 1024 is used by the refresh microcode to refresh the Orbit memory.
+                        // We log this separately to make debugging more clear.
+                        //
+                        if (_height == 1024)
+                        {
+                            Log.Write(LogComponent.Orbit, "Image band completed (refresh).");
+                        }
+                        else
+                        {
+                            Log.Write(LogComponent.Orbit, "Image band completed.");
+                        }
+
+                        UpdateWakeup();
                         break;
                     }
                 }
             }
-
-            _firstWord = false;
-            Log.Write(LogComponent.Orbit,
-               "Font Data: {0}", Conversion.ToOctal(value));
         }
 
         public void WriteInkData(ushort value)
@@ -387,7 +462,7 @@ namespace Contralto.IO
         public ushort GetDBCWidth()
         {
             Log.Write(LogComponent.Orbit,
-                "Delta DBCWidth {0},{1}", _deltaBCEnd % 16, _width);
+                "Delta DBCWidth {0},{1}", _deltaBCEnd % 16, _width);           
 
             return (ushort)((_deltaBCEnd << 12) | (_width & 0xfff));
         }
@@ -417,7 +492,7 @@ namespace Contralto.IO
             }
 
             Log.Write(LogComponent.Orbit,
-                "OrbitStatus {0}", Conversion.ToOctal(result));
+                "OrbitStatus, address {0}, {1}", _statusAddress, Conversion.ToOctal(result));
 
             return (ushort)result;
         }
@@ -425,7 +500,7 @@ namespace Contralto.IO
         private ushort GetOutputData()
         {
             //
-            // Basically, the function OrbitOutputData reads 16 bits from the output buffer
+            // "Basically, the function OrbitOutputData reads 16 bits from the output buffer
             // into the Alto.  
             //
             //  The programmer (or emulator author) needs to be aware of two tricky details
@@ -437,7 +512,7 @@ namespace Contralto.IO
             //      The usual convention is to read out this one last word.  This leaves the first
             //      word of the new buffer in ROB.
             //
-            //  2. The output band buffer will not be refreshed ... (not a concern here)
+            //  2. The output band buffer will not be refreshed ... [not a concern here]"
             //
 
             // Return the last value from ROB
@@ -456,7 +531,7 @@ namespace Contralto.IO
 
             if (_outputY == 256)
             {
-                Log.Write(LogComponent.DoverROS,
+                Log.Write(LogComponent.Orbit,
                     "OutputData - scanline {0} completed", _outputX);
 
                 _outputY = _fa;
@@ -466,7 +541,7 @@ namespace Contralto.IO
                 {
                     // Done reading output band -- swap buffers!
 
-                    Log.Write(LogComponent.DoverROS,
+                    Log.Write(LogComponent.Orbit,
                         "OutputData - buffer read completed.");
 
                     SwapBuffers();
@@ -494,23 +569,22 @@ namespace Contralto.IO
             // the Alto is now behind the consumer...
             //
             if (!_goAway)
-            {
-                Console.WriteLine("BEHIND");
+            {                
                 _behind = true;
             }
             else
             {
                 // "The buffer switch will turn off GOAWAY and consequently
                 //  allow wakeups again."
-                _goAway = false;
-                _system.CPU.WakeupTask(CPU.TaskType.Orbit);
+                _goAway = false;             
+                UpdateWakeup();
             }
 
             // Flip buffer bit
             _incon = !_incon;
         }
 
-        private void SetImageRasterBit(int x, int y, int bitValue)
+        private void SetImageRasterBit(int x, int y)
         {
             // Pick out the word we're interested in
             int wordAddress = y >> 4;
@@ -526,21 +600,22 @@ namespace Contralto.IO
         {
             _refresh = true;
 
-            //Log.Write(LogComponent.Orbit, "Refresh signal raised.");
+            Log.Write(LogComponent.Orbit, "Refresh signal raised.");
 
             if (_run)
             {
-                _system.CPU.WakeupTask(CPU.TaskType.Orbit);
-
                 // do it again
                 _refreshEvent.TimestampNsec = _refreshInterval;
                 _system.Scheduler.Schedule(_refreshEvent);
             }
             else
             {
-                //Log.Write(LogComponent.Orbit, "RUN deasserted, Refresh aborted.");
+                Log.Write(LogComponent.Orbit, "RUN deasserted, Refresh aborted.");
                 _refreshRunning = false;
+                _refresh = false;
             }
+
+            UpdateWakeup();
         }
 
         // Run status
@@ -553,9 +628,7 @@ namespace Contralto.IO
         private int _width;     // raster width of character
         private int _bitCount;  // count of processed bits; used to calculate DeltaWC.
         private int _deltaBC;   // bit of first word to start with
-        private int _deltaBCEnd; // number of bits left in last word rasterized
-
-        private int _scanlines;
+        private int _deltaBCEnd; // number of bits left in last word rasterized        
 
         // FA -- "First Address" of each scanline -- a value between
         // 0 and 255 indicating the starting word to be read by the
@@ -630,7 +703,7 @@ namespace Contralto.IO
         private readonly ulong _refreshInterval = 2 * Conversion.MsecToNsec;   // 2ms in nsec
 
         //
-        // The ROS we talk to to get raster onto a "page"
+        // The ROS we talk to to get raster onto a page.
         //
         private DoverROS _ros;
 

Contralto/IO/OrganKeyboard.cs

@@ -1,11 +1,23 @@
-using Contralto.CPU;
+/*  
+    This file is part of ContrAlto.
+
+    ContrAlto is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Affero General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ContrAlto is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Affero General Public License for more details.
+
+    You should have received a copy of the GNU Affero General Public License
+    along with ContrAlto.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+using Contralto.CPU;
 using Contralto.Logging;
 using Contralto.Memory;
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
 
 namespace Contralto.IO
 {

Contralto/IO/Printing/IPageSink.cs

@@ -0,0 +1,43 @@
+/*  
+    This file is part of ContrAlto.
+
+    ContrAlto is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Affero General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ContrAlto is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Affero General Public License for more details.
+
+    You should have received a copy of the GNU Affero General Public License
+    along with ContrAlto.  If not, see <http://www.gnu.org/licenses/>.
+*/
+namespace Contralto.IO.Printing
+{
+    /// <summary>
+    /// IPageSink defines the interface between a ROS device and physical output
+    /// on the emulated host (be it real paper on a printer or PDF, Postscript, etc).    
+    /// </summary>
+    public interface IPageSink
+    {
+        /// <summary>
+        /// Starts a new document to be printed.
+        /// </summary>        
+        void StartDoc();
+
+        /// <summary>
+        /// Adds a new page to the output.  This is provided as a byte array containing 'height' scanlines of the specified width.
+        /// </summary>
+        /// <param name="raster"></param>
+        /// <param name="width"></param>
+        /// <param name="height"></param>
+        void AddPage(byte[] raster, int width, int height);
+
+        /// <summary>
+        /// Ends the document being printed.
+        /// </summary>
+        void EndDoc();
+    }
+}

Contralto/IO/Printing/NullPageSink.cs

@@ -0,0 +1,44 @@
+/*  
+    This file is part of ContrAlto.
+
+    ContrAlto is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Affero General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ContrAlto is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Affero General Public License for more details.
+
+    You should have received a copy of the GNU Affero General Public License
+    along with ContrAlto.  If not, see <http://www.gnu.org/licenses/>.
+*/
+namespace Contralto.IO.Printing
+{
+    /// <summary>
+    /// The NullPageSink:  All pages go to the bit-bucket, for the true paperless office.
+    /// </summary>
+    public class NullPageSink : IPageSink
+    {
+        public NullPageSink()
+        {
+            
+        }
+
+        public void StartDoc()
+        {
+
+        }
+
+        public void AddPage(byte[] rasters, int width, int height)
+        {
+            
+        }
+
+        public void EndDoc()
+        {
+            
+        }
+    }
+}

Contralto/IO/Printing/PdfPageSink.cs

@@ -0,0 +1,127 @@
+/*  
+    This file is part of ContrAlto.
+
+    ContrAlto is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Affero General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ContrAlto is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Affero General Public License for more details.
+
+    You should have received a copy of the GNU Affero General Public License
+    along with ContrAlto.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+using System.IO;
+
+using iTextSharp.text;
+using iTextSharp.text.pdf;
+using System.Collections.Generic;
+using System;
+using Contralto.Logging;
+
+namespace Contralto.IO.Printing
+{
+    /// <summary>
+    /// PdfPageSink takes output from the ROS and turns it into
+    /// PDF documents in the PrintOutputPath folder.
+    /// 
+    /// This uses the iTextSharp PDF creation libraries to do the hard work.
+    /// </summary>
+    public class PdfPageSink : IPageSink
+    {
+        public PdfPageSink()
+        {
+            _pageImages = new List<Image>();
+        }
+
+        public void StartDoc()
+        {
+            _pageImages.Clear();
+
+            try
+            {
+                // Start a new document.
+                // All output to a Dover printer is letter-sized.
+                _pdf = new Document(PageSize.LETTER);
+
+                string path = Path.Combine(
+                    Configuration.PrintOutputPath,
+                    String.Format("AltoDocument-{0}.pdf", DateTime.Now.ToString("yyyyMMdd-hhmmss")));
+
+                PdfWriter writer = PdfWriter.GetInstance(
+                    _pdf,
+                    new FileStream(path, FileMode.Create));
+
+                _pdf.Open();
+
+                // Let the Orbit deal with the margins.
+                _pdf.SetMargins(0, 0, 0, 0);
+            }
+            catch(Exception e)
+            {
+                //
+                // Most likely we couldn't create the output file; log the failure.
+                // All output will be relegated to the bit bucket.
+                //
+                _pdf = null;
+
+                Log.Write(LogType.Error, LogComponent.DoverROS, "Failed to create output PDF.  Error {0}", e.Message);
+            }
+        }
+
+        public void AddPage(byte[] rasters, int width, int height)
+        {
+            if (_pdf != null)
+            {
+                Image pageImage = iTextSharp.text.Image.GetInstance(height, width, 1 /* greyscale */, 1 /* 1bpp */, rasters);
+                pageImage.SetDpi(375, 375);
+                pageImage.SetAbsolutePosition(0, 0);
+                pageImage.RotationDegrees = 90;
+                pageImage.ScaleToFit(_pdf.PageSize);
+
+                _pageImages.Add(pageImage);
+            }
+        }
+
+        public void EndDoc()
+        {
+            if (_pdf != null)
+            {
+                try
+                {
+                    // Grab the configuration here so that if some joker changes the configuration
+                    // while we're printing we don't do something weird.
+                    bool reversePageOrder = Configuration.ReversePageOrder;
+
+                    // Actually write out the pages now, in the proper order.
+                    for (int i = 0; i < _pageImages.Count; i++)
+                    {
+                        _pdf.Add(_pageImages[reversePageOrder ? (_pageImages.Count - 1) - i : i]);
+                        _pdf.NewPage();
+                    }
+
+                    _pdf.Close();
+                }
+                catch (Exception e)
+                {
+                    // Something bad happened during creation, log an error.
+                    Log.Write(LogComponent.DoverROS, "Failed to create output PDF.  Error {0}", e.Message);
+                }
+            }
+        }
+
+        /// <summary>
+        /// List of page images in this document.
+        /// Since Alto software typically prints the document in reverse-page-order due to the way the 
+        /// Dover produces output, we need be able to produce the PDF in reverse order.
+        /// This uses extra memory, (about 1.7mb per page printed.)
+        /// </summary>
+        private List<Image> _pageImages;
+
+        private Document _pdf;
+    }
+}

Contralto/Memory/MemoryBus.cs

@@ -78,9 +78,8 @@ namespace Contralto.Memory
             _memoryCycle = 0;
             _memoryAddress = 0;
             _memoryDataLow = 0;
-            _memoryDataHigh = 0;
-            _firstWordStored = false;
-            _firstWordRead = false;
+            _memoryDataHigh = 0;            
+            _firstWord = false;
             _memoryOperationActive = false;
             _extendedMemoryReference = false;            
         }
@@ -186,7 +185,7 @@ namespace Contralto.Memory
 
                 case 6:
                     // End of memory operation
-                    _memoryOperationActive = false;                    
+                    _memoryOperationActive = false;
                     break;
             }
         }
@@ -245,14 +244,18 @@ namespace Contralto.Memory
             }
             else
             {
-                _memoryOperationActive = true;
-                _firstWordStored = false;
-                _firstWordRead = false;
+                _memoryOperationActive = true;                
+                _firstWord = false;
                 _memoryAddress = address;
                 _extendedMemoryReference = extendedMemoryReference;
                 _task = task;
+
+                //
+                // Memory cycle 1 is the instruction in which a MAR<- is executed, 
+                // per the convention in the Alto HW ref.
+                //
                 _memoryCycle = 1;
-            }                                 
+            }
             
         }        
 
@@ -285,12 +288,12 @@ namespace Contralto.Memory
                         throw new InvalidOperationException("Invalid ReadMD request during cycle 3 or 4 of memory operation.");
 
                     case 5:
-                        // Single word read                       
+                        // Single word read
                         return _memoryDataLow;
 
                     case 6:
                         // Double word read, return other half of double word.
-                        return _memoryDataHigh;                                         
+                        return _memoryDataHigh;
 
                     default:
                         // Invalid state.
@@ -324,12 +327,15 @@ namespace Contralto.Memory
                         //   If this is memory cycle 5 of a double-word *store* (started in cycle 3) then the second word can be *read* here.
                         //   (An example of this is provided in the hardware ref, section 2, pg 8. and is done by the Ethernet microcode on 
                         //   the Alto II, see the code block starting at address 0224 -- EPLOC (600) is loaded with the interface status, 
-                        //   EBLOC (601) is read and OR'd with NWW in the same memory op.)                
-                        _firstWordRead = true;                        
-                        return _firstWordStored ? _memoryDataHigh : _memoryDataLow;
+                        //   EBLOC (601) is read and OR'd with NWW in the same memory op.)                                        
+                        ushort memData = _firstWord ? _memoryDataHigh : _memoryDataLow;
+
+                        _firstWord = !_firstWord;
+
+                        return memData;
 
                     // ***
-                    // NB: Handler for double-word read (cycle 6) is in the "else" clause below; this is kind of a hack.
+                    // NB: Handler for double-word read (cycles 6 and later) is in the "else" clause below; this is kind of a hack.
                     // ***
 
                     default:
@@ -341,12 +347,19 @@ namespace Contralto.Memory
             {
                 //
                 // Memory state machine not running, just return last latched contents.
-                // ("Because the Alto II latches memory contents, it is possible to execute _MD anytime after
+                // ("Because the Alto II latches memory contents, it is possible to execute <-MD anytime after
                 // cycle 5 of a reference and obtain the results of the read operation")
-                // We will return the last half of the doubleword to complete a double-word read.
-                // (If the first half hasn't yet been read, we return the first half instead...)
-                //                
-                return _firstWordRead ? _memoryDataHigh : _memoryDataLow;                
+                // We will return the proper half of the word as in cycle 5.
+                //
+                // Note that the Orbit character transfer microcode will occasionally do a double-word read in memory 
+                // cycles 6 and 7, not 5 and 6, and still expect the correct 32-bit double-word to be read...
+                // 
+                ushort memData;
+                
+                memData = _firstWord ? _memoryDataHigh : _memoryDataLow;
+                
+                _firstWord = !_firstWord;
+                return memData;
             }            
         }
 
@@ -392,11 +405,11 @@ namespace Contralto.Memory
                     _memoryDataWrite = data;
                     // Start of doubleword write:
                     WriteToBus(_memoryAddress, data, _task, _extendedMemoryReference);
-                    _firstWordStored = true;
+                    _firstWord = !_firstWord;
                     break;
 
                 case 6:
-                    if (!_firstWordStored)
+                    if (!_firstWord)
                     {
                         throw new InvalidOperationException("Unexpected microcode behavior -- LoadMD on cycle 6, no LoadMD on cycle 5.");
                     }
@@ -405,6 +418,8 @@ namespace Contralto.Memory
                     ushort actualAddress = (ushort)(_memoryAddress | 1);
 
                     WriteToBus(actualAddress, data, _task, _extendedMemoryReference);
+
+                    _firstWord = !_firstWord;
                     break;
             }
 
@@ -424,13 +439,14 @@ namespace Contralto.Memory
                     _memoryDataWrite = data;
                     // Start of doubleword write:
                     WriteToBus(_memoryAddress, data, _task, _extendedMemoryReference);
-                    _firstWordStored = true;                    
+                    _firstWord = !_firstWord;
                     break;
 
                 case 4:
                     _memoryDataWrite = data;
-                    ushort actualAddress = _firstWordStored ? (ushort)(_memoryAddress ^ 1) : _memoryAddress;                    
+                    ushort actualAddress = _firstWord ? (ushort)(_memoryAddress ^ 1) : _memoryAddress;                    
                     WriteToBus(actualAddress, data, _task, _extendedMemoryReference);
+                    _firstWord = !_firstWord;
                     break;
 
                 case 5:
@@ -533,10 +549,9 @@ namespace Contralto.Memory
         // Write data (used for debugger UI only)
         private ushort _memoryDataWrite;
 
-        // Indicates that the first word of a double-word store has taken place (started on cycle 3)
-        private bool _firstWordStored;
 
-        // Indicates tghat the first word of a double-word read has taken place (started on cycle 5)
-        private bool _firstWordRead;
+        // Indicates which word of a double-word read or write was last read (or written).
+        // true if the first word was processed; false otherwise.
+        private bool _firstWord;
     }
 }

Contralto/Program.cs

@@ -15,10 +15,8 @@
     along with ContrAlto.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-using Contralto.IO;
 using Contralto.SdlUI;
 using System;
-using System.Collections.Generic;
 using System.Windows.Forms;
 
 namespace Contralto
@@ -121,16 +119,15 @@ namespace Contralto
             // Commit current configuration to disk
             //
             Configuration.WriteConfiguration();
-
         }
 
         private static void PrintHerald()
         {
-            Console.WriteLine("ContrAlto v1.2 (c) 2015-2017 Living Computers: Museum+Labs.");            
+            Console.WriteLine("ContrAlto v{0} (c) 2015-2017 Living Computers: Museum+Labs.", typeof(Program).Assembly.GetName().Version);
             Console.WriteLine("Bug reports to joshd@livingcomputers.org");
             Console.WriteLine();
         }      
         
-        private static AltoSystem _system;        
+        private static AltoSystem _system;
     }
 }

Contralto/Properties/AssemblyInfo.cs

@@ -32,5 +32,5 @@ using System.Runtime.InteropServices;
 // You can specify all the values or you can default the Build and Revision Numbers 
 // by using the '*' as shown below:
 // [assembly: AssemblyVersion("1.0.*")]
-[assembly: AssemblyVersion("1.2.0")]
-[assembly: AssemblyFileVersion("1.2.0.0")]
+[assembly: AssemblyVersion("1.2.1")]
+[assembly: AssemblyFileVersion("1.2.1.0")]

Contralto/Properties/Settings.Designer.cs

@@ -202,5 +202,41 @@ namespace Contralto.Properties {
                 this["AudioDACCapturePath"] = value;
             }
         }
+        
+        [global::System.Configuration.UserScopedSettingAttribute()]
+        [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
+        [global::System.Configuration.DefaultSettingValueAttribute("False")]
+        public bool EnablePrinting {
+            get {
+                return ((bool)(this["EnablePrinting"]));
+            }
+            set {
+                this["EnablePrinting"] = value;
+            }
+        }
+        
+        [global::System.Configuration.UserScopedSettingAttribute()]
+        [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
+        [global::System.Configuration.DefaultSettingValueAttribute("")]
+        public string PrintOutputPath {
+            get {
+                return ((string)(this["PrintOutputPath"]));
+            }
+            set {
+                this["PrintOutputPath"] = value;
+            }
+        }
+        
+        [global::System.Configuration.UserScopedSettingAttribute()]
+        [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
+        [global::System.Configuration.DefaultSettingValueAttribute("True")]
+        public bool ReversePageOrder {
+            get {
+                return ((bool)(this["ReversePageOrder"]));
+            }
+            set {
+                this["ReversePageOrder"] = value;
+            }
+        }
     }
 }

Contralto/Properties/Settings.settings

@@ -47,5 +47,14 @@
     <Setting Name="AudioDACCapturePath" Type="System.String" Scope="User">
       <Value Profile="(Default)" />
     </Setting>
+    <Setting Name="EnablePrinting" Type="System.Boolean" Scope="User">
+      <Value Profile="(Default)">False</Value>
+    </Setting>
+    <Setting Name="PrintOutputPath" Type="System.String" Scope="User">
+      <Value Profile="(Default)" />
+    </Setting>
+    <Setting Name="ReversePageOrder" Type="System.Boolean" Scope="User">
+      <Value Profile="(Default)">True</Value>
+    </Setting>
   </Settings>
 </SettingsFile>

Contralto/UI/AboutBox.Designer.cs

@@ -52,11 +52,11 @@
             // label2
             // 
             this.label2.AutoSize = true;
-            this.label2.Location = new System.Drawing.Point(20, 59);
+            this.label2.Location = new System.Drawing.Point(6, 58);
             this.label2.Name = "label2";
-            this.label2.Size = new System.Drawing.Size(46, 13);
+            this.label2.Size = new System.Drawing.Size(76, 13);
             this.label2.TabIndex = 1;
-            this.label2.Text = "(c) 2016";
+            this.label2.Text = "(c) 2016, 2017";
             // 
             // label3
             // 
@@ -109,7 +109,7 @@
             // websiteLink
             // 
             this.websiteLink.AutoSize = true;
-            this.websiteLink.Location = new System.Drawing.Point(65, 59);
+            this.websiteLink.Location = new System.Drawing.Point(80, 59);
             this.websiteLink.Name = "websiteLink";
             this.websiteLink.Size = new System.Drawing.Size(163, 13);
             this.websiteLink.TabIndex = 7;

Contralto/UI/Debugger.Designer.cs

@@ -109,9 +109,6 @@
             this.StopButton = new System.Windows.Forms.Button();
             this.groupBox2 = new System.Windows.Forms.GroupBox();
             this._taskData = new System.Windows.Forms.DataGridView();
-            this.TaskName = new System.Windows.Forms.DataGridViewTextBoxColumn();
-            this.TaskState = new System.Windows.Forms.DataGridViewTextBoxColumn();
-            this.TaskPC = new System.Windows.Forms.DataGridViewTextBoxColumn();
             this.groupBox3 = new System.Windows.Forms.GroupBox();
             this._otherRegs = new System.Windows.Forms.DataGridView();
             this.Reg = new System.Windows.Forms.DataGridViewTextBoxColumn();
@@ -136,6 +133,10 @@
             this.dataGridViewTextBoxColumn9 = new System.Windows.Forms.DataGridViewTextBoxColumn();
             this.dataGridViewTextBoxColumn10 = new System.Windows.Forms.DataGridViewTextBoxColumn();
             this.dataGridViewTextBoxColumn11 = new System.Windows.Forms.DataGridViewTextBoxColumn();
+            this.TaskName = new System.Windows.Forms.DataGridViewTextBoxColumn();
+            this.TaskState = new System.Windows.Forms.DataGridViewTextBoxColumn();
+            this.Bank = new System.Windows.Forms.DataGridViewTextBoxColumn();
+            this.TaskPC = new System.Windows.Forms.DataGridViewTextBoxColumn();
             this.Microcode.SuspendLayout();
             this.SourceTabs.SuspendLayout();
             this.Rom0Page.SuspendLayout();
@@ -855,6 +856,7 @@
             this._taskData.Columns.AddRange(new System.Windows.Forms.DataGridViewColumn[] {
             this.TaskName,
             this.TaskState,
+            this.Bank,
             this.TaskPC});
             dataGridViewCellStyle29.Alignment = System.Windows.Forms.DataGridViewContentAlignment.MiddleLeft;
             dataGridViewCellStyle29.BackColor = System.Drawing.SystemColors.Window;
@@ -881,31 +883,6 @@
             this._taskData.TabIndex = 0;
             this._taskData.TabStop = false;
             // 
-            // TaskName
-            // 
-            this.TaskName.AutoSizeMode = System.Windows.Forms.DataGridViewAutoSizeColumnMode.AllCellsExceptHeader;
-            this.TaskName.HeaderText = "T";
-            this.TaskName.MinimumWidth = 16;
-            this.TaskName.Name = "TaskName";
-            this.TaskName.ReadOnly = true;
-            this.TaskName.Width = 16;
-            // 
-            // TaskState
-            // 
-            this.TaskState.AutoSizeMode = System.Windows.Forms.DataGridViewAutoSizeColumnMode.DisplayedCellsExceptHeader;
-            this.TaskState.HeaderText = "S";
-            this.TaskState.MinimumWidth = 16;
-            this.TaskState.Name = "TaskState";
-            this.TaskState.ReadOnly = true;
-            this.TaskState.Width = 16;
-            // 
-            // TaskPC
-            // 
-            this.TaskPC.AutoSizeMode = System.Windows.Forms.DataGridViewAutoSizeColumnMode.Fill;
-            this.TaskPC.HeaderText = "uPC";
-            this.TaskPC.Name = "TaskPC";
-            this.TaskPC.ReadOnly = true;
-            // 
             // groupBox3
             // 
             this.groupBox3.Controls.Add(this._otherRegs);
@@ -1234,6 +1211,40 @@
             this.dataGridViewTextBoxColumn11.Resizable = System.Windows.Forms.DataGridViewTriState.False;
             this.dataGridViewTextBoxColumn11.SortMode = System.Windows.Forms.DataGridViewColumnSortMode.NotSortable;
             // 
+            // TaskName
+            // 
+            this.TaskName.AutoSizeMode = System.Windows.Forms.DataGridViewAutoSizeColumnMode.AllCellsExceptHeader;
+            this.TaskName.HeaderText = "T";
+            this.TaskName.MinimumWidth = 16;
+            this.TaskName.Name = "TaskName";
+            this.TaskName.ReadOnly = true;
+            this.TaskName.Width = 16;
+            // 
+            // TaskState
+            // 
+            this.TaskState.AutoSizeMode = System.Windows.Forms.DataGridViewAutoSizeColumnMode.DisplayedCellsExceptHeader;
+            this.TaskState.HeaderText = "S";
+            this.TaskState.MinimumWidth = 16;
+            this.TaskState.Name = "TaskState";
+            this.TaskState.ReadOnly = true;
+            this.TaskState.Width = 16;
+            // 
+            // Bank
+            // 
+            this.Bank.AutoSizeMode = System.Windows.Forms.DataGridViewAutoSizeColumnMode.AllCellsExceptHeader;
+            this.Bank.HeaderText = "B";
+            this.Bank.MinimumWidth = 16;
+            this.Bank.Name = "Bank";
+            this.Bank.ReadOnly = true;
+            this.Bank.Width = 16;
+            // 
+            // TaskPC
+            // 
+            this.TaskPC.AutoSizeMode = System.Windows.Forms.DataGridViewAutoSizeColumnMode.Fill;
+            this.TaskPC.HeaderText = "uPC";
+            this.TaskPC.Name = "TaskPC";
+            this.TaskPC.ReadOnly = true;
+            // 
             // Debugger
             // 
             this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
@@ -1306,9 +1317,6 @@
         private System.Windows.Forms.DataGridViewTextBoxColumn S;
         private System.Windows.Forms.GroupBox groupBox2;
         private System.Windows.Forms.DataGridView _taskData;
-        private System.Windows.Forms.DataGridViewTextBoxColumn TaskName;
-        private System.Windows.Forms.DataGridViewTextBoxColumn TaskState;
-        private System.Windows.Forms.DataGridViewTextBoxColumn TaskPC;
         private System.Windows.Forms.GroupBox groupBox3;
         private System.Windows.Forms.DataGridView _otherRegs;
         private System.Windows.Forms.DataGridViewTextBoxColumn Reg;
@@ -1366,5 +1374,9 @@
         private System.Windows.Forms.DataGridViewTextBoxColumn Address;
         private System.Windows.Forms.DataGridViewTextBoxColumn Data;
         private System.Windows.Forms.DataGridViewTextBoxColumn Disassembly;
+        private System.Windows.Forms.DataGridViewTextBoxColumn TaskName;
+        private System.Windows.Forms.DataGridViewTextBoxColumn TaskState;
+        private System.Windows.Forms.DataGridViewTextBoxColumn Bank;
+        private System.Windows.Forms.DataGridViewTextBoxColumn TaskPC;
     }
 }

Contralto/UI/Debugger.cs

@@ -116,7 +116,8 @@ namespace Contralto
             {
                 _taskData.Rows[i].Cells[0].Value = GetTextForTask((TaskType)i);
                 _taskData.Rows[i].Cells[1].Value = GetTextForTaskState(_system.CPU.Tasks[i]);
-                _taskData.Rows[i].Cells[2].Value =
+                _taskData.Rows[i].Cells[2].Value = GetTextForTaskBank(_system.CPU.Tasks[i]);
+                _taskData.Rows[i].Cells[3].Value =
                     _system.CPU.Tasks[i] != null ? Conversion.ToOctal(_system.CPU.Tasks[i].MPC, 4) : String.Empty;
             }
 
@@ -532,7 +533,7 @@ namespace Contralto
                 case "Disassembly":
                     // TODO: should provide means to disassemble as specific task, not just Emulator.
                     MicroInstruction instruction = new MicroInstruction(UCodeMemory.UCodeRAM[address]);
-                    e.Value = UCodeDisassembler.DisassembleInstruction(instruction, TaskType.Emulator);
+                    e.Value = UCodeDisassembler.DisassembleInstruction(instruction, _system.CPU.CurrentTask.TaskType);
                     break;
             }
         }
@@ -578,6 +579,18 @@ namespace Contralto
             }
         }
 
+        private string GetTextForTaskBank(AltoCPU.Task task)
+        {
+            if (task == null)
+            {
+                return String.Empty;
+            }
+            else
+            {
+                return UCodeMemory.GetBank(task.TaskType).ToString();                
+            }
+        }
+
         private string GetTextForTask(TaskType task)
         {
             string[] taskText =
@@ -931,38 +944,13 @@ namespace Contralto
                 case ExecutionType.Normal:
                 case ExecutionType.NextTask:
                 case ExecutionType.NextNovaInstruction:
-
-                    // For debugging floating point microcode:
-#if FLOAT_DEBUG
-                    if (_system.CPU.CurrentTask.MPC == 0x10)                     // MPC is 20(octal) meaning a new Nova instruction.
-                    {
-                        if (_lastFPInstruction == 0)
-                        {
-                            // check for new floating instruction
-                            FloatDebugPre(_system.MemoryBus.DebugReadWord(TaskType.Emulator, _system.CPU.R[6]));
-                        }
-                        else
-                        {
-                            // last instruction was a floating point instruction, check the result
-                            FloatDebugPost();
-
-                            // And see if this new one is also a floating point instruction...
-                            FloatDebugPre(_system.MemoryBus.DebugReadWord(TaskType.Emulator, _system.CPU.R[6]));
-                        }
-                    } 
-#endif
-                    if (_system.CPU.CurrentTask.MPC == 0x10)                     // MPC is 20(octal) meaning a new Nova instruction.
-                    {
-                        // count nova instructions (for profiling)
-                        _system._novaInst++;
-                    }
-
                     // See if we need to stop here
                     if (_execAbort ||                                               // The Stop button was hit
+                        _system.CPU.InternalBreak ||                                // Something internal has requested a debugger break
                         _microcodeBreakpointEnabled[
                             (int)UCodeMemory.GetBank(
                                 _system.CPU.CurrentTask.TaskType), 
-                                _system.CPU.CurrentTask.MPC] || // A microcode breakpoint was hit
+                                _system.CPU.CurrentTask.MPC] ||                     // A microcode breakpoint was hit
                         (_execType == ExecutionType.NextTask &&
                             _system.CPU.NextTask != null &&
                             _system.CPU.NextTask != _system.CPU.CurrentTask) ||     // The next task was switched to                    
@@ -970,15 +958,17 @@ namespace Contralto
                             (_novaBreakpointEnabled[_system.CPU.R[6]] ||            // A breakpoint is set here
                              _execType == ExecutionType.NextNovaInstruction)))      // or we're running only a single Nova instruction.                              
                     {
+                        if (!_execAbort)
+                        {
+                            SetExecutionState(ExecutionState.BreakpointStop);
+                        }
+
                         // Stop here as we've hit a breakpoint or have been stopped 
                         // Update UI to indicate where we stopped.
                         this.BeginInvoke(new StepDelegate(RefreshUI));
                         this.BeginInvoke(new StepDelegate(Invalidate));
 
-                        if (!_execAbort)
-                        {
-                            SetExecutionState(ExecutionState.BreakpointStop);
-                        }
+                        _system.CPU.InternalBreak = false;                       
 
                         _execAbort = false;
                         return true;
@@ -990,379 +980,7 @@ namespace Contralto
             return false;
         }
 
-#if FLOAT_DEBUG
-        // vars for float debug
-        ushort _lastFPInstruction;
-        ushort _ac0;
-        ushort _ac1;
-        ushort _ac2;
-        ushort _ac3;
-        ushort _fpRegAddr;
-        ushort _fpRegCount;
 
-        int _fpInstructionCount;
-
-        /// <summary>
-        /// Temporary, for debugging floating point ucode issues
-        /// </summary>
-        /// <param name="instruction"></param>
-        private void FloatDebugPre(ushort instruction)
-        {
-            _lastFPInstruction = 0;
-            // Float instructions are from 70001-70022 octal
-            if (instruction >= 0x7000 && instruction <= 0x7012)
-            {
-                _fpInstructionCount++;
-
-                // Save instruction
-                _lastFPInstruction = instruction;
-
-                // Save ACs
-                _ac0 = _system.CPU.R[3];
-                _ac1 = _system.CPU.R[2];
-                _ac2 = _system.CPU.R[1];
-                _ac3 = _system.CPU.R[0];
-
-                Console.Write("{0}:FP: ", _fpInstructionCount);
-                switch (instruction)
-                {
-                    case 0x7000:
-                        Console.WriteLine("FPSetup");
-
-                        _fpRegAddr = _system.CPU.R[3];
-                        _fpRegCount = _system.MemoryBus.DebugReadWord(TaskType.Emulator, _fpRegAddr);
-
-                        Console.WriteLine(" FP register address {0}, count {1}", Conversion.ToOctal(_fpRegAddr), _fpRegCount);
-
-                        break;
-
-                    case 0x7001:
-                        Console.WriteLine("FML {0},{1} ({2},{3})", _ac0, _ac1, GetFloat(_ac0), GetFloat(_ac1));                        
-                        break;
-
-                    case 0x7002:                        
-                        Console.WriteLine("FDV {0},{1} ({2},{3})", _ac0, _ac1, GetFloat(_ac0), GetFloat(_ac1));                        
-                        break;
-
-                    case 0x7003:                        
-                        Console.WriteLine("FAD {0},{1} ({2},{3})", _ac0, _ac1, GetFloat(_ac0), GetFloat(_ac1));                        
-                        break;
-
-                    case 0x7004:
-                        Console.WriteLine("FSB {0},{1} ({2},{3})", _ac0, _ac1, GetFloat(_ac0), GetFloat(_ac1));                        
-                        break;
-
-                    case 0x7005:
-                        Console.WriteLine("FLD {0},{1} (src {2})", _ac0, _ac1, GetFloat(_ac1));                        
-                        break;
-
-                    case 0x7006:
-                        Console.WriteLine("FLDV {0},{1} (src {2})", _ac0, _ac1, GetFloatFromInternalFormat(_ac1));                        
-                        break;
-
-                    case 0x7007:
-                        Console.WriteLine("FSTV {0},{1} (src {2})", _ac0, _ac1, GetFloat(_ac0));
-                        break;
-
-                    case 0x7008:
-                        Console.WriteLine("FLDI {0},{1}", _ac0, Conversion.ToOctal(_ac1));
-                        break;
-
-                    case 0x7009:
-                        Console.WriteLine("FTR {0} ({1})", _ac0, GetFloat(_ac0));                        
-                        break;
-
-                    case 0x700a:
-                        Console.WriteLine("FNEG {0} ({1})", _ac0, GetFloat(_ac0));                        
-                        break;
-
-                    case 0x700b:
-                        Console.WriteLine("FSN {0} ({1})", _ac0, GetFloat(_ac0));
-                        break;
-
-                    case 0x700c:
-                        Console.WriteLine("FCM {0} ({1})", _ac0, GetFloat(_ac0));
-                        break;
-
-                    case 0x700d:
-                        Console.WriteLine("FST");
-                        break;
-
-                    case 0x700e:
-                        Console.WriteLine("FLDDP");
-                        break;
-
-                    case 0x700f:
-                        Console.WriteLine("FSTDP");
-                        break;
-
-                    case 0x7010:
-                        Console.WriteLine("DPAD");
-                        break;
-
-                    case 0x7011:
-                        Console.WriteLine("DPSB");
-                        break;
-
-                    case 0x7012:
-                        Console.WriteLine("FEXP {0},{1} ({2})", _ac0, _ac1, GetFloat(_ac0));
-                        break;
-                }                
-
-                /*
-                Console.WriteLine(" AC0={0} AC1={1} AC2={2} AC3={3}",
-                    Conversion.ToOctal(_ac0),
-                    Conversion.ToOctal(_ac1),
-                    Conversion.ToOctal(_ac2),
-                    Conversion.ToOctal(_ac3)); */
-            }            
-        }
-
-        private void FloatDebugPost()
-        {            
-
-            Console.Write("{0}:Post: ", _fpInstructionCount);
-            switch (_lastFPInstruction)
-            {
-                case 0x7000:
-                    Console.WriteLine("FPSetup done.");
-                    break;
-
-                case 0x7001:
-                    Console.WriteLine("Result {0}", GetFloat(_ac0));
-                    break;
-
-                case 0x7002:
-                    Console.WriteLine("Result {0}", GetFloat(_ac0));
-                    break;
-
-                case 0x7003:
-                    Console.WriteLine("Result {0}", GetFloat(_ac0));
-                    break;
-
-                case 0x7004:
-                    Console.WriteLine("Result {0}", GetFloat(_ac0));
-                    break;
-
-                case 0x7005:
-                    Console.WriteLine("Loaded {0}", GetFloat(_ac0));
-                    break;
-
-                case 0x7006:
-                    Console.WriteLine("Loaded {0}", GetFloat(_ac0));
-                    break;
-
-                case 0x7007:
-                    Console.WriteLine("FSTV done.");
-                    break;
-
-                case 0x7008:
-                    Console.WriteLine("Loaded {0}", GetFloat(_ac0));
-                    break;
-
-                case 0x7009:
-                    Console.WriteLine("Result {0}", GetFloat(_ac0));
-                    break;
-
-                case 0x700a:
-                    Console.WriteLine("Result {0}", GetFloat(_ac0));
-                    break;
-
-                case 0x700b:
-                    Console.WriteLine("Result {0}", _ac3);
-                    break;
-
-                case 0x700c:
-                    Console.WriteLine("Result {0}", _ac3);
-                    break;
-
-                case 0x700d:
-                    Console.WriteLine("FST done.");
-                    break;
-
-                case 0x700e:
-                    Console.WriteLine("FLDDP done.");
-                    break;
-
-                case 0x700f:
-                    Console.WriteLine("FSTDP done.");
-                    break;
-
-                case 0x7010:
-                    Console.WriteLine("DPAD done.");
-                    break;
-
-                case 0x7011:
-                    Console.WriteLine("DPSB done.");
-                    break;
-
-                case 0x7012:
-                    Console.WriteLine("Result {0}", GetFloat(_ac0));
-                    break;
-
-                default:
-                    throw new InvalidOperationException("Unexpected op for post.");
-            }
-
-            _lastFPInstruction = 0;
-        }
-
-        private double GetFloat(ushort arg)
-        {
-            // If arg is less than the number of registers, it's assumed
-            // to be a register; otherwise an address
-            if (arg < _fpRegCount)
-            {
-                return GetFloatFromUcode(arg);
-            }
-            else
-            {
-                return GetFloatFromPackedFormat(arg);
-            }
-        }
-
-        /// <summary>
-        /// Gets a float from memory in "packed" format
-        /// </summary>
-        /// <param name="addr"></param>
-        /// <returns></returns>
-        private double GetFloatFromPackedFormat(ushort addr)
-        {
-            //
-            // Packed format is only two words:
-            // structure FP: [
-            //   sign bit 1     //1 if negative.
-            //   expon bit 8    //excess 128 format (complemented if number <0)
-            //   mantissa1 bit 7 //High order 7 bits of mantissa
-            //   mantissa2 bit 16 //Low order 16 bits of mantissa
-            //   ]
-            //
-            uint packedWord = 
-                (uint)(_system.MemoryBus.DebugReadWord(TaskType.Emulator, addr) << 16) |
-                (uint)(_system.MemoryBus.DebugReadWord(TaskType.Emulator, (ushort)(addr + 1)));
-
-            double sign = (packedWord &   0x80000000) != 0 ? -1.0 : 1.0;
-            uint exponent = (packedWord & 0x7f800000) >> 23;
-            uint mantissa = (packedWord & 0x007fffff);
-
-            double val = 0.0;
-            for (int i = 0; i < 23; i++)
-            {
-                double bit = (mantissa & (0x00400000 >> i)) != 0 ? 1.0 : 0.0;
-
-                val += (bit * (1.0 / Math.Pow(2.0, (double)i)));
-            }
-
-            double adjustedExponent = exponent - 128.0;
-
-            val = sign * (val) * Math.Pow(2.0, adjustedExponent);
-
-            Console.WriteLine("packed: {0}", val);
-
-            return val;
-
-        }
-
-        /// <summary>
-        /// Gets the float value for register, from alto code
-        /// </summary>
-        /// <param name="reg"></param>
-        /// <returns></returns>
-        private double GetFloatFromInternalFormat(ushort addr)
-        {
-
-            // Internal format is 4 words long:
-            //  Word 0: sign
-            //  Word 1: exponent
-            //  Word 2-3: mantissa
-            //            
-            
-            double sign = (_system.MemoryBus.DebugReadWord(TaskType.Emulator, addr)) != 0 ? -1.0 : 1.0;
-            int exponent = (int)(short)(_system.MemoryBus.DebugReadWord(TaskType.Emulator, (ushort)(addr + 1)));
-            uint mantissa =
-                (uint)(_system.MemoryBus.DebugReadWord(TaskType.Emulator, (ushort)(addr + 2)) << 16) |
-                (uint)(_system.MemoryBus.DebugReadWord(TaskType.Emulator, (ushort)(addr + 3)));
-            
-            double valMantissa = 0.0;
-            for (int i = 0; i < 32; i++)
-            {
-                double bit = (mantissa & (0x80000000 >> i)) != 0 ? 1.0 : 0.0;
-
-                valMantissa += (bit * (1.0 / Math.Pow(2.0, (double)i)));
-            }                        
-
-            double val = sign * (valMantissa) * Math.Pow(2.0, exponent - 1);
-
-            //if (double.IsInfinity(val) || double.IsNaN(val))
-            {
-                Console.WriteLine(" Vec: sign {0} exp {1} mantissa {2:x} ({3}) value {4}",
-                    sign,
-                    exponent,
-                    mantissa,
-                    valMantissa,
-                    val);
-            }
-
-            return val;
-        }
-
-        /// <summary>
-        /// Gets the float value for register, from ucode store
-        /// </summary>
-        /// <param name="reg"></param>
-        /// <returns></returns>
-        private double GetFloatFromUcode(ushort reg)
-        {
-
-            // Internal format is 4 words long:
-            //  Word 0: sign
-            //  Word 1: exponent
-            //  Word 2-3: mantissa
-            //
-            // In current ucode, each word is staggered across the FP buffer space rather than being in linear order to prevent having to do multiplies.
-            // For FP register N of M total registers starting at offset O:
-            // Word 0 is at O + N + 1
-            // Word 1 is at O + N + M + 1
-            // Word 2 is at O + N + 2*M + 1
-            // Word 3 is at O + N + 3*M + 1            
-            ushort oreg = reg;
-
-
-            reg += _fpRegAddr;
-            reg++;
-
-            //Console.WriteLine("reg base {0}, num {1} addr {2}", _fpRegAddr, oreg, Conversion.ToOctal(reg));
-
-            // reg is now an address; read things in...
-            double sign = (_system.MemoryBus.DebugReadWord(TaskType.Emulator, reg)) != 0 ? -1.0 : 1.0;
-            int exponent = (int)(short)(_system.MemoryBus.DebugReadWord(TaskType.Emulator, (ushort)(reg + _fpRegCount)));
-            uint mantissa =
-                (uint)(_system.MemoryBus.DebugReadWord(TaskType.Emulator, (ushort)(reg + 2 * _fpRegCount)) << 16) |
-                (uint)(_system.MemoryBus.DebugReadWord(TaskType.Emulator, (ushort)(reg + 3 * _fpRegCount)));
-
-            double valMantissa = 0.0;
-            for (int i = 0; i < 32; i++)
-            {
-                double bit = (mantissa & (0x80000000 >> i)) != 0 ? 1.0 : 0.0;
-
-                valMantissa += (bit * (1.0 / Math.Pow(2.0, (double)i)));                
-            }
-
-            double val = sign * (valMantissa) * Math.Pow(2.0, exponent - 1);
-
-            //if (double.IsInfinity(val) || double.IsNaN(val))
-            {
-                Console.WriteLine(" UCode: sign {0} exp {1} mantissa {2:x} ({3}) value {4}",
-                    sign,
-                    exponent,
-                    mantissa,
-                    valMantissa,
-                    val);
-            }
-
-            return val;
-        }
-#endif
         private void SetExecutionState(ExecutionState state)
         {
             _execState = state;

Contralto/UI/Debugger.resx

@@ -192,6 +192,9 @@
   <metadata name="TaskState.UserAddedColumn" type="System.Boolean, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">
     <value>True</value>
   </metadata>
+  <metadata name="Bank.UserAddedColumn" type="System.Boolean, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">
+    <value>True</value>
+  </metadata>
   <metadata name="TaskPC.UserAddedColumn" type="System.Boolean, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">
     <value>True</value>
   </metadata>

Contralto/UI/SystemOptions.Designer.cs

@@ -28,7 +28,7 @@
         /// </summary>
         private void InitializeComponent()
         {
-            this.tabControl1 = new System.Windows.Forms.TabControl();
+            this.OptionsTabs = new System.Windows.Forms.TabControl();
             this.tabPage1 = new System.Windows.Forms.TabPage();
             this.AltoI1KROMRadioButton = new System.Windows.Forms.RadioButton();
             this.AltoII3KRAMRadioButton = new System.Windows.Forms.RadioButton();
@@ -48,16 +48,23 @@
             this.tabPage3 = new System.Windows.Forms.TabPage();
             this.ThrottleSpeedCheckBox = new System.Windows.Forms.CheckBox();
             this.InterlaceDisplayCheckBox = new System.Windows.Forms.CheckBox();
+            this.tabPage4 = new System.Windows.Forms.TabPage();
+            this.DACOptionsGroupBox = new System.Windows.Forms.GroupBox();
+            this.BrowseButton = new System.Windows.Forms.Button();
+            this.DACOutputCapturePathTextBox = new System.Windows.Forms.TextBox();
+            this.label2 = new System.Windows.Forms.Label();
+            this.EnableDACCaptureCheckBox = new System.Windows.Forms.CheckBox();
+            this.EnableDACCheckBox = new System.Windows.Forms.CheckBox();
             this.DialogOKButton = new System.Windows.Forms.Button();
             this.DialogCancelButton = new System.Windows.Forms.Button();
-            this.tabPage4 = new System.Windows.Forms.TabPage();
-            this.EnableDACCheckBox = new System.Windows.Forms.CheckBox();
-            this.DACOptionsGroupBox = new System.Windows.Forms.GroupBox();
-            this.EnableDACCaptureCheckBox = new System.Windows.Forms.CheckBox();
-            this.label2 = new System.Windows.Forms.Label();
-            this.DACOutputCapturePathTextBox = new System.Windows.Forms.TextBox();
-            this.BrowseButton = new System.Windows.Forms.Button();
-            this.tabControl1.SuspendLayout();
+            this.PrintingTab = new System.Windows.Forms.TabPage();
+            this.PrintingOptionsGroupBox = new System.Windows.Forms.GroupBox();
+            this.button1 = new System.Windows.Forms.Button();
+            this.PrintOutputPathTextBox = new System.Windows.Forms.TextBox();
+            this.label5 = new System.Windows.Forms.Label();
+            this.EnablePrintingCheckBox = new System.Windows.Forms.CheckBox();
+            this.ReversePageOrderCheckBox = new System.Windows.Forms.CheckBox();
+            this.OptionsTabs.SuspendLayout();
             this.tabPage1.SuspendLayout();
             this.tabPage2.SuspendLayout();
             this.groupBox1.SuspendLayout();
@@ -65,19 +72,22 @@
             this.tabPage3.SuspendLayout();
             this.tabPage4.SuspendLayout();
             this.DACOptionsGroupBox.SuspendLayout();
+            this.PrintingTab.SuspendLayout();
+            this.PrintingOptionsGroupBox.SuspendLayout();
             this.SuspendLayout();
             // 
-            // tabControl1
+            // OptionsTabs
             // 
-            this.tabControl1.Controls.Add(this.tabPage1);
-            this.tabControl1.Controls.Add(this.tabPage2);
-            this.tabControl1.Controls.Add(this.tabPage3);
-            this.tabControl1.Controls.Add(this.tabPage4);
-            this.tabControl1.Location = new System.Drawing.Point(3, 5);
-            this.tabControl1.Name = "tabControl1";
-            this.tabControl1.SelectedIndex = 0;
-            this.tabControl1.Size = new System.Drawing.Size(368, 227);
-            this.tabControl1.TabIndex = 0;
+            this.OptionsTabs.Controls.Add(this.tabPage1);
+            this.OptionsTabs.Controls.Add(this.tabPage2);
+            this.OptionsTabs.Controls.Add(this.tabPage3);
+            this.OptionsTabs.Controls.Add(this.tabPage4);
+            this.OptionsTabs.Controls.Add(this.PrintingTab);
+            this.OptionsTabs.Location = new System.Drawing.Point(3, 5);
+            this.OptionsTabs.Name = "OptionsTabs";
+            this.OptionsTabs.SelectedIndex = 0;
+            this.OptionsTabs.Size = new System.Drawing.Size(368, 227);
+            this.OptionsTabs.TabIndex = 0;
             // 
             // tabPage1
             // 
@@ -101,7 +111,6 @@
             this.AltoI1KROMRadioButton.Name = "AltoI1KROMRadioButton";
             this.AltoI1KROMRadioButton.Size = new System.Drawing.Size(214, 17);
             this.AltoI1KROMRadioButton.TabIndex = 4;
-            this.AltoI1KROMRadioButton.TabStop = true;
             this.AltoI1KROMRadioButton.Text = "Alto I, 1K Control ROM, 1K Control RAM";
             this.AltoI1KROMRadioButton.UseVisualStyleBackColor = true;
             // 
@@ -112,7 +121,6 @@
             this.AltoII3KRAMRadioButton.Name = "AltoII3KRAMRadioButton";
             this.AltoII3KRAMRadioButton.Size = new System.Drawing.Size(236, 17);
             this.AltoII3KRAMRadioButton.TabIndex = 3;
-            this.AltoII3KRAMRadioButton.TabStop = true;
             this.AltoII3KRAMRadioButton.Text = "Alto II XM, 1K Control ROM, 3K Control RAM";
             this.AltoII3KRAMRadioButton.UseVisualStyleBackColor = true;
             this.AltoII3KRAMRadioButton.CheckedChanged += new System.EventHandler(this.OnSystemTypeCheckChanged);
@@ -124,7 +132,6 @@
             this.AltoII2KROMRadioButton.Name = "AltoII2KROMRadioButton";
             this.AltoII2KROMRadioButton.Size = new System.Drawing.Size(236, 17);
             this.AltoII2KROMRadioButton.TabIndex = 2;
-            this.AltoII2KROMRadioButton.TabStop = true;
             this.AltoII2KROMRadioButton.Text = "Alto II XM, 2K Control ROM, 1K Control RAM";
             this.AltoII2KROMRadioButton.UseVisualStyleBackColor = true;
             this.AltoII2KROMRadioButton.CheckedChanged += new System.EventHandler(this.OnSystemTypeCheckChanged);
@@ -141,6 +148,7 @@
             // AltoII1KROMRadioButton
             // 
             this.AltoII1KROMRadioButton.AutoSize = true;
+            this.AltoII1KROMRadioButton.Checked = true;
             this.AltoII1KROMRadioButton.Location = new System.Drawing.Point(14, 53);
             this.AltoII1KROMRadioButton.Name = "AltoII1KROMRadioButton";
             this.AltoII1KROMRadioButton.Size = new System.Drawing.Size(236, 17);
@@ -287,6 +295,79 @@
             this.InterlaceDisplayCheckBox.Text = "Interlaced Display (headache mode)";
             this.InterlaceDisplayCheckBox.UseVisualStyleBackColor = true;
             // 
+            // tabPage4
+            // 
+            this.tabPage4.Controls.Add(this.DACOptionsGroupBox);
+            this.tabPage4.Controls.Add(this.EnableDACCheckBox);
+            this.tabPage4.Location = new System.Drawing.Point(4, 22);
+            this.tabPage4.Name = "tabPage4";
+            this.tabPage4.Padding = new System.Windows.Forms.Padding(3);
+            this.tabPage4.Size = new System.Drawing.Size(360, 201);
+            this.tabPage4.TabIndex = 3;
+            this.tabPage4.Text = "DAC";
+            this.tabPage4.UseVisualStyleBackColor = true;
+            // 
+            // DACOptionsGroupBox
+            // 
+            this.DACOptionsGroupBox.Controls.Add(this.BrowseButton);
+            this.DACOptionsGroupBox.Controls.Add(this.DACOutputCapturePathTextBox);
+            this.DACOptionsGroupBox.Controls.Add(this.label2);
+            this.DACOptionsGroupBox.Controls.Add(this.EnableDACCaptureCheckBox);
+            this.DACOptionsGroupBox.Location = new System.Drawing.Point(15, 52);
+            this.DACOptionsGroupBox.Name = "DACOptionsGroupBox";
+            this.DACOptionsGroupBox.Size = new System.Drawing.Size(335, 139);
+            this.DACOptionsGroupBox.TabIndex = 1;
+            this.DACOptionsGroupBox.TabStop = false;
+            this.DACOptionsGroupBox.Text = "DAC options";
+            // 
+            // BrowseButton
+            // 
+            this.BrowseButton.Location = new System.Drawing.Point(251, 53);
+            this.BrowseButton.Name = "BrowseButton";
+            this.BrowseButton.Size = new System.Drawing.Size(75, 23);
+            this.BrowseButton.TabIndex = 3;
+            this.BrowseButton.Text = "Browse...";
+            this.BrowseButton.UseVisualStyleBackColor = true;
+            this.BrowseButton.Click += new System.EventHandler(this.BrowseButton_Click);
+            // 
+            // DACOutputCapturePathTextBox
+            // 
+            this.DACOutputCapturePathTextBox.Location = new System.Drawing.Point(127, 55);
+            this.DACOutputCapturePathTextBox.Name = "DACOutputCapturePathTextBox";
+            this.DACOutputCapturePathTextBox.Size = new System.Drawing.Size(110, 20);
+            this.DACOutputCapturePathTextBox.TabIndex = 2;
+            // 
+            // label2
+            // 
+            this.label2.AutoSize = true;
+            this.label2.Location = new System.Drawing.Point(16, 58);
+            this.label2.Name = "label2";
+            this.label2.Size = new System.Drawing.Size(105, 13);
+            this.label2.TabIndex = 1;
+            this.label2.Text = "Output capture path:";
+            // 
+            // EnableDACCaptureCheckBox
+            // 
+            this.EnableDACCaptureCheckBox.AutoSize = true;
+            this.EnableDACCaptureCheckBox.Location = new System.Drawing.Point(18, 28);
+            this.EnableDACCaptureCheckBox.Name = "EnableDACCaptureCheckBox";
+            this.EnableDACCaptureCheckBox.Size = new System.Drawing.Size(156, 17);
+            this.EnableDACCaptureCheckBox.TabIndex = 0;
+            this.EnableDACCaptureCheckBox.Text = "Enable DAC output capture";
+            this.EnableDACCaptureCheckBox.UseVisualStyleBackColor = true;
+            this.EnableDACCaptureCheckBox.CheckedChanged += new System.EventHandler(this.EnableDACCaptureCheckBox_CheckedChanged);
+            // 
+            // EnableDACCheckBox
+            // 
+            this.EnableDACCheckBox.AutoSize = true;
+            this.EnableDACCheckBox.Location = new System.Drawing.Point(19, 22);
+            this.EnableDACCheckBox.Name = "EnableDACCheckBox";
+            this.EnableDACCheckBox.Size = new System.Drawing.Size(275, 17);
+            this.EnableDACCheckBox.TabIndex = 0;
+            this.EnableDACCheckBox.Text = "Enable Audio DAC (Used by Smalltalk Music System)";
+            this.EnableDACCheckBox.UseVisualStyleBackColor = true;
+            this.EnableDACCheckBox.CheckedChanged += new System.EventHandler(this.OnEnableDACCheckboxChanged);
+            // 
             // DialogOKButton
             // 
             this.DialogOKButton.Location = new System.Drawing.Point(211, 239);
@@ -307,78 +388,76 @@
             this.DialogCancelButton.UseVisualStyleBackColor = true;
             this.DialogCancelButton.Click += new System.EventHandler(this.CancelButton_Click);
             // 
-            // tabPage4
+            // PrintingTab
             // 
-            this.tabPage4.Controls.Add(this.DACOptionsGroupBox);
-            this.tabPage4.Controls.Add(this.EnableDACCheckBox);
-            this.tabPage4.Location = new System.Drawing.Point(4, 22);
-            this.tabPage4.Name = "tabPage4";
-            this.tabPage4.Padding = new System.Windows.Forms.Padding(3);
-            this.tabPage4.Size = new System.Drawing.Size(360, 201);
-            this.tabPage4.TabIndex = 3;
-            this.tabPage4.Text = "DAC";
-            this.tabPage4.UseVisualStyleBackColor = true;
+            this.PrintingTab.Controls.Add(this.PrintingOptionsGroupBox);
+            this.PrintingTab.Controls.Add(this.EnablePrintingCheckBox);
+            this.PrintingTab.Location = new System.Drawing.Point(4, 22);
+            this.PrintingTab.Name = "PrintingTab";
+            this.PrintingTab.Padding = new System.Windows.Forms.Padding(3);
+            this.PrintingTab.Size = new System.Drawing.Size(360, 201);
+            this.PrintingTab.TabIndex = 4;
+            this.PrintingTab.Text = "Printing";
+            this.PrintingTab.UseVisualStyleBackColor = true;
             // 
-            // EnableDACCheckBox
+            // PrintingOptionsGroupBox
             // 
-            this.EnableDACCheckBox.AutoSize = true;
-            this.EnableDACCheckBox.Location = new System.Drawing.Point(19, 22);
-            this.EnableDACCheckBox.Name = "EnableDACCheckBox";
-            this.EnableDACCheckBox.Size = new System.Drawing.Size(275, 17);
-            this.EnableDACCheckBox.TabIndex = 0;
-            this.EnableDACCheckBox.Text = "Enable Audio DAC (Used by Smalltalk Music System)";
-            this.EnableDACCheckBox.UseVisualStyleBackColor = true;
-            this.EnableDACCheckBox.CheckedChanged += new System.EventHandler(this.OnEnableDACCheckboxChanged);
+            this.PrintingOptionsGroupBox.Controls.Add(this.ReversePageOrderCheckBox);
+            this.PrintingOptionsGroupBox.Controls.Add(this.button1);
+            this.PrintingOptionsGroupBox.Controls.Add(this.PrintOutputPathTextBox);
+            this.PrintingOptionsGroupBox.Controls.Add(this.label5);
+            this.PrintingOptionsGroupBox.Location = new System.Drawing.Point(14, 52);
+            this.PrintingOptionsGroupBox.Name = "PrintingOptionsGroupBox";
+            this.PrintingOptionsGroupBox.Size = new System.Drawing.Size(335, 139);
+            this.PrintingOptionsGroupBox.TabIndex = 3;
+            this.PrintingOptionsGroupBox.TabStop = false;
+            this.PrintingOptionsGroupBox.Text = "Printing options";
             // 
-            // DACOptionsGroupBox
+            // button1
             // 
-            this.DACOptionsGroupBox.Controls.Add(this.BrowseButton);
-            this.DACOptionsGroupBox.Controls.Add(this.DACOutputCapturePathTextBox);
-            this.DACOptionsGroupBox.Controls.Add(this.label2);
-            this.DACOptionsGroupBox.Controls.Add(this.EnableDACCaptureCheckBox);
-            this.DACOptionsGroupBox.Location = new System.Drawing.Point(15, 52);
-            this.DACOptionsGroupBox.Name = "DACOptionsGroupBox";
-            this.DACOptionsGroupBox.Size = new System.Drawing.Size(335, 139);
-            this.DACOptionsGroupBox.TabIndex = 1;
-            this.DACOptionsGroupBox.TabStop = false;
-            this.DACOptionsGroupBox.Text = "DAC options";
+            this.button1.Location = new System.Drawing.Point(254, 24);
+            this.button1.Name = "button1";
+            this.button1.Size = new System.Drawing.Size(75, 23);
+            this.button1.TabIndex = 3;
+            this.button1.Text = "Browse...";
+            this.button1.UseVisualStyleBackColor = true;
             // 
-            // EnableDACCaptureCheckBox
+            // PrintOutputPathTextBox
             // 
-            this.EnableDACCaptureCheckBox.AutoSize = true;
-            this.EnableDACCaptureCheckBox.Location = new System.Drawing.Point(18, 28);
-            this.EnableDACCaptureCheckBox.Name = "EnableDACCaptureCheckBox";
-            this.EnableDACCaptureCheckBox.Size = new System.Drawing.Size(156, 17);
-            this.EnableDACCaptureCheckBox.TabIndex = 0;
-            this.EnableDACCaptureCheckBox.Text = "Enable DAC output capture";
-            this.EnableDACCaptureCheckBox.UseVisualStyleBackColor = true;
-            this.EnableDACCaptureCheckBox.CheckedChanged += new System.EventHandler(this.EnableDACCaptureCheckBox_CheckedChanged);
+            this.PrintOutputPathTextBox.Location = new System.Drawing.Point(113, 25);
+            this.PrintOutputPathTextBox.Name = "PrintOutputPathTextBox";
+            this.PrintOutputPathTextBox.Size = new System.Drawing.Size(125, 20);
+            this.PrintOutputPathTextBox.TabIndex = 2;
             // 
-            // label2
+            // label5
             // 
-            this.label2.AutoSize = true;
-            this.label2.Location = new System.Drawing.Point(16, 58);
-            this.label2.Name = "label2";
-            this.label2.Size = new System.Drawing.Size(105, 13);
-            this.label2.TabIndex = 1;
-            this.label2.Text = "Output capture path:";
+            this.label5.AutoSize = true;
+            this.label5.Location = new System.Drawing.Point(19, 28);
+            this.label5.Name = "label5";
+            this.label5.Size = new System.Drawing.Size(88, 13);
+            this.label5.TabIndex = 1;
+            this.label5.Text = "PDF output path:";
             // 
-            // DACOutputCapturePathTextBox
+            // EnablePrintingCheckBox
             // 
-            this.DACOutputCapturePathTextBox.Location = new System.Drawing.Point(127, 55);
-            this.DACOutputCapturePathTextBox.Name = "DACOutputCapturePathTextBox";
-            this.DACOutputCapturePathTextBox.Size = new System.Drawing.Size(110, 20);
-            this.DACOutputCapturePathTextBox.TabIndex = 2;
+            this.EnablePrintingCheckBox.AutoSize = true;
+            this.EnablePrintingCheckBox.Location = new System.Drawing.Point(19, 22);
+            this.EnablePrintingCheckBox.Name = "EnablePrintingCheckBox";
+            this.EnablePrintingCheckBox.Size = new System.Drawing.Size(211, 17);
+            this.EnablePrintingCheckBox.TabIndex = 2;
+            this.EnablePrintingCheckBox.Text = "Enable Printing (via Orbit / Dover ROS)";
+            this.EnablePrintingCheckBox.UseVisualStyleBackColor = true;
+            this.EnablePrintingCheckBox.CheckedChanged += new System.EventHandler(this.EnablePrintingCheckBox_CheckedChanged);
             // 
-            // BrowseButton
+            // ReversePageOrderCheckBox
             // 
-            this.BrowseButton.Location = new System.Drawing.Point(251, 53);
-            this.BrowseButton.Name = "BrowseButton";
-            this.BrowseButton.Size = new System.Drawing.Size(75, 23);
-            this.BrowseButton.TabIndex = 3;
-            this.BrowseButton.Text = "Browse...";
-            this.BrowseButton.UseVisualStyleBackColor = true;
-            this.BrowseButton.Click += new System.EventHandler(this.BrowseButton_Click);
+            this.ReversePageOrderCheckBox.AutoSize = true;
+            this.ReversePageOrderCheckBox.Location = new System.Drawing.Point(22, 51);
+            this.ReversePageOrderCheckBox.Name = "ReversePageOrderCheckBox";
+            this.ReversePageOrderCheckBox.Size = new System.Drawing.Size(158, 17);
+            this.ReversePageOrderCheckBox.TabIndex = 4;
+            this.ReversePageOrderCheckBox.Text = "Reverse Output Page Order";
+            this.ReversePageOrderCheckBox.UseVisualStyleBackColor = true;
             // 
             // SystemOptions
             // 
@@ -387,12 +466,12 @@
             this.ClientSize = new System.Drawing.Size(371, 271);
             this.Controls.Add(this.DialogCancelButton);
             this.Controls.Add(this.DialogOKButton);
-            this.Controls.Add(this.tabControl1);
+            this.Controls.Add(this.OptionsTabs);
             this.Name = "SystemOptions";
             this.SizeGripStyle = System.Windows.Forms.SizeGripStyle.Hide;
             this.StartPosition = System.Windows.Forms.FormStartPosition.CenterParent;
             this.Text = "System Options";
-            this.tabControl1.ResumeLayout(false);
+            this.OptionsTabs.ResumeLayout(false);
             this.tabPage1.ResumeLayout(false);
             this.tabPage1.PerformLayout();
             this.tabPage2.ResumeLayout(false);
@@ -407,13 +486,17 @@
             this.tabPage4.PerformLayout();
             this.DACOptionsGroupBox.ResumeLayout(false);
             this.DACOptionsGroupBox.PerformLayout();
+            this.PrintingTab.ResumeLayout(false);
+            this.PrintingTab.PerformLayout();
+            this.PrintingOptionsGroupBox.ResumeLayout(false);
+            this.PrintingOptionsGroupBox.PerformLayout();
             this.ResumeLayout(false);
 
         }
 
         #endregion
 
-        private System.Windows.Forms.TabControl tabControl1;
+        private System.Windows.Forms.TabControl OptionsTabs;
         private System.Windows.Forms.TabPage tabPage1;
         private System.Windows.Forms.RadioButton AltoII3KRAMRadioButton;
         private System.Windows.Forms.RadioButton AltoII2KROMRadioButton;
@@ -442,5 +525,12 @@
         private System.Windows.Forms.Button BrowseButton;
         private System.Windows.Forms.TextBox DACOutputCapturePathTextBox;
         private System.Windows.Forms.Label label2;
+        private System.Windows.Forms.TabPage PrintingTab;
+        private System.Windows.Forms.GroupBox PrintingOptionsGroupBox;
+        private System.Windows.Forms.Button button1;
+        private System.Windows.Forms.TextBox PrintOutputPathTextBox;
+        private System.Windows.Forms.Label label5;
+        private System.Windows.Forms.CheckBox EnablePrintingCheckBox;
+        private System.Windows.Forms.CheckBox ReversePageOrderCheckBox;
     }
 }

Contralto/UI/SystemOptions.cs

@@ -113,6 +113,15 @@ namespace Contralto.UI
 
             DACOutputCapturePathTextBox.Text = Configuration.AudioDACCapturePath;
             EnableDACCaptureCheckBox.Checked = Configuration.EnableAudioDACCapture;
+
+            //
+            // Printing Tab
+            //
+            PrintOutputPathTextBox.Text = Configuration.PrintOutputPath;
+            EnablePrintingCheckBox.Checked = Configuration.EnablePrinting;                        
+            PrintingOptionsGroupBox.Enabled = Configuration.EnablePrinting;
+            ReversePageOrderCheckBox.Checked = Configuration.ReversePageOrder;
+
         }
 
         private void PopulateNetworkAdapterList(PacketInterfaceType encapType)
@@ -273,10 +282,21 @@ namespace Contralto.UI
             Configuration.EnableAudioDACCapture = EnableDACCaptureCheckBox.Checked;
             Configuration.AudioDACCapturePath = DACOutputCapturePathTextBox.Text;
 
-            // Validate that the output folder exists, if not, warn the user
+            // Printing
+            Configuration.EnablePrinting = EnablePrintingCheckBox.Checked;
+            Configuration.PrintOutputPath = PrintOutputPathTextBox.Text;
+            Configuration.ReversePageOrder = ReversePageOrderCheckBox.Checked;
+
+            // Validate that the DAC output folder exists, if not, warn the user
             if (Configuration.EnableAudioDACCapture && !Directory.Exists(Configuration.AudioDACCapturePath))
             {
-                MessageBox.Show("Warning: the specified DAC output capture path does not exist or is inaccessible.");
+                MessageBox.Show("Warning: The specified DAC output capture path does not exist or is inaccessible.");
+            }
+
+            // Validate that the Print output folder exists, if not, warn the user
+            if (Configuration.EnablePrinting && !Directory.Exists(Configuration.PrintOutputPath))
+            {
+                MessageBox.Show("Warning: The specified Print output path does not exist or is inaccessible.");
             }
 
             this.Close();
@@ -306,11 +326,15 @@ namespace Contralto.UI
             {
                 DACOutputCapturePathTextBox.Text = folderDialog.SelectedPath;
             }
-        }
+            else
+            {
+                EnableDACCaptureCheckBox.Checked = false;
+            }
+        }        
 
         private void OnEnableDACCheckboxChanged(object sender, EventArgs e)
         {
-            DACOptionsGroupBox.Enabled = Configuration.EnableAudioDAC;
+            DACOptionsGroupBox.Enabled = EnableDACCheckBox.Checked;
         }
 
         private void EnableDACCaptureCheckBox_CheckedChanged(object sender, EventArgs e)
@@ -318,10 +342,38 @@ namespace Contralto.UI
             if (EnableDACCaptureCheckBox.Checked == true && String.IsNullOrWhiteSpace(DACOutputCapturePathTextBox.Text))
             {
                 //
-                // When enabled and no output folder is set, force the user to choose an output folder.
+                // When DAC enabled and no output folder is set, force the user to choose an output folder.
                 //
                 BrowseForDACOutputFolder();
             }
         }
+
+        private void BrowseForPrintOutputFolder()
+        {
+            FolderBrowserDialog folderDialog = new FolderBrowserDialog();
+            folderDialog.Description = "Choose a folder to store PDFs of print output.";
+            folderDialog.ShowNewFolderButton = true;
+
+            if (folderDialog.ShowDialog() == DialogResult.OK)
+            {
+                PrintOutputPathTextBox.Text = folderDialog.SelectedPath;
+            }
+            else
+            {
+                EnablePrintingCheckBox.Checked = false;
+            }
+        }
+
+        private void EnablePrintingCheckBox_CheckedChanged(object sender, EventArgs e)
+        {
+            PrintingOptionsGroupBox.Enabled = EnablePrintingCheckBox.Checked;            
+            if (EnablePrintingCheckBox.Checked == true && String.IsNullOrWhiteSpace(PrintOutputPathTextBox.Text))
+            {
+                //
+                // When Printing enabled and no output folder is set, force the user to choose an output folder.
+                //
+                BrowseForPrintOutputFolder();
+            }
+        }
     }
 }

Contralto/packages.config

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
+  <package id="iTextSharp" version="5.5.11" targetFramework="net452" />
   <package id="NAudio" version="1.8.0" targetFramework="net452" />
   <package id="SDL2-CS.dll" version="2.0.0.0" targetFramework="net452" />
   <package id="Sharp_Pcap" version="4.2.0" targetFramework="net452" />

Contralto/readme-mono.txt

@@ -20,13 +20,14 @@ ContrAlto currently emulates the following Alto hardware:
    - Ethernet (encapsulated in UDP datagrams on the host machine)
    - Standard Keyboard/Mouse/Video
    - Audio DAC (used with the Smalltalk Music System)
+   - The Orbit raster hardware, Dover Raster Output Scanner and Dover print
+     engine, which provides 384dpi print output (currently PDF only)
 
 1.2 What's Not
 --------------
 
 At this time, ContrAlto does not support more exotic hardware such as Trident 
-disks, printers or audio using the utility port, the Orbit printer interface, or the 
-keyset input device.
+disks, printers or audio using the utility port, or the keyset input device.
 
 The Audio DAC is technically emulated, but output is not connected to an audio
 device on non-Windows platforms at this time.
@@ -263,6 +264,11 @@ An example configuration file looks something like:
     BootFile = 0
     AlternateBootType = Ethernet
 
+    # Printing options
+    EnablePrinting = true
+    PrintOutputPath = .
+    ReversePageOrder = true
+
 
 The following parameters are configurable:
 
@@ -294,6 +300,19 @@ BootAddress: The address to use with a Keyboard Disk Boot (See section 5.0)
 BootFile:    The file number to use with a Keyboard Net Boot (again, Section 5.0)
 AlternateBootType:  The type of boot to default to (Section 5.0)
 
+EnablePrinting:     Enables or disables printing via the emulated Orbit / Dover interface.
+
+PrintOutputPath:    Specifies the folder that output PDFs are written to. When the  Alto 
+                    prints a new document, a new PDF file will be created in this
+                    directory containing the printer's output.
+
+ReversePageOrder:   Controls the order in which pages are written to the PDF -- due to 
+                    the way the original Dover printer worked, most Alto software printed 
+                    documents in reverse order (i.e. the last page printed first) so 
+                    that the pages didn't have to be reshuffled when picked up from the
+                    tray.  By default, leaving this box checked is probably what you want, 
+                    but if your documents come out backwards, uncheck it.
+
 
 4.1 Ethernet Encapsulation Setup
 ================================
@@ -452,10 +471,17 @@ On Unix and OS X, display and keyboard/mouse input is provided through SDL, see:
 https://www.libsdl.org/ and is accessed using the SDL2# wrapper, see:
 https://github.com/flibitijibibo/SDL2-CS.
 
+PDF generation is provided by the iTextSharp library, see: https://github.com/itext.
 
 10.0 Change History
 ===================
 
+V1.2.1
+------
+- Completed implementation of Orbit, Dover ROS and Dover print engine.
+- Bugfixes to memory state machine around overlapped double-word reads/writes.
+  Smalltalk-80 now runs, as does Spruce.
+
 V1.2
 ----
 - First release supporting Unix / OS X

Contralto/readme.txt

@@ -21,13 +21,14 @@ ContrAlto currently emulates the following Alto hardware:
                on the host machine)
    - Standard Keyboard/Mouse/Video
    - Audio DAC (used with the Smalltalk Music System)
+   - The Orbit raster hardware, Dover Raster Output Scanner and Dover print
+     engine, which provides 384dpi print output (currently PDF only)
 
 1.2 What's Not
 --------------
 
 At this time, ContrAlto does not support more exotic hardware such as Trident 
-disks, printers or audio using the utility port, the Orbit printer interface, or the 
-keyset input device.
+disks, printers or audio using the utility port or the keyset input device.
 
 
 2.0 Requirements
@@ -297,11 +298,12 @@ The "Interlaced Display" checkbox attempts to simulate the Alto's original
 interlaced display.  Depending on your monitor and the speed of your computer
 this may or may not work well.
 
+
 4.4 DAC
 -------
 
 The DAC tab provides options controlling the Audio DAC used by the Smalltalk
-Music System.  The "Enable Audio DAC" does what you'd expect -- it enables
+Music System.  "Enable Audio DAC" does what you'd expect -- it enables
 or disables audio output (and audio capture).  If this option is enabled,
 the "DAC Options" fields become available.
 
@@ -313,7 +315,26 @@ directory.  If the Alto is restarted or if ContrAlto exits, this file will
 be closed.  WAV files created by ContrAlto are 16-bit, mono at 13Khz.
 
 
-4.5 Alternate ("keyboard") Boots
+4.5 Printing
+------------
+
+The Printing tab provides options for the Orbit / Dover print system emulation.
+The "Enable Printing" checkbox enables or disables print output.  If this option
+is enabled, the "Printing Options" fields become available.
+
+The "PDF output path" specifies the folder that output PDFs are written to.
+When the Alto prints a new document, a new PDF file will be created in this
+directory containing the printer's output.
+
+The "Reverse Output Page Order" checkbox controls the order in which pages are
+written to the PDF -- due to the way the original Dover printer worked, most
+Alto software printed pages in reverse order (i.e. the last page printed
+first) so that the pages didn't have to be reshuffled when picked up from the
+tray.  By default, leaving this box checked is probably what you want, but
+if your documents come out backwards, uncheck it.
+
+
+4.6 Alternate ("keyboard") Boots
 --------------------------------
 
 The Alto allowed the specification of alternate boot addresses by holding down
@@ -493,10 +514,18 @@ On Unix and OS X, display and keyboard/mouse input is provided through SDL, see:
 https://www.libsdl.org/ and is accessed using the SDL2# wrapper, see:
 https://github.com/flibitijibibo/SDL2-CS.
 
+PDF generation is provided by the iTextSharp library, see: https://github.com/itext.
+
 
 10.0 Change History
 ===================
 
+V1.2.1
+------
+- Completed implementation of Orbit, Dover ROS and Dover print engine.
+- Bugfixes to memory state machine around overlapped double-word reads/writes.
+  Smalltalk-80 now runs, as does Spruce.
+
 V1.2
 ----
 - First release officially supporting Unix / OS X