diff --git a/src/main/java/jace/JaceApplication.java b/src/main/java/jace/JaceApplication.java
index 576cf79..c11d048 100644
--- a/src/main/java/jace/JaceApplication.java
+++ b/src/main/java/jace/JaceApplication.java
@@ -47,7 +47,7 @@ public class JaceApplication extends Application {
             Scene s = new Scene(node);
             primaryStage.setScene(s);
             primaryStage.setTitle("Jace");
-            primaryStage.getIcons().add(Utility.loadIcon("woz_figure.gif"));
+            Utility.loadIcon("woz_figure.gif").ifPresent(primaryStage.getIcons()::add);
         } catch (IOException exception) {
             throw new RuntimeException(exception);
         }
@@ -86,7 +86,7 @@ public class JaceApplication extends Application {
                 Scene s = new Scene(node);
                 cheatStage.setScene(s);
                 cheatStage.setTitle("Jace: MetaCheat");
-                cheatStage.getIcons().add(Utility.loadIcon("woz_figure.gif"));
+                Utility.loadIcon("woz_figure.gif").ifPresent(cheatStage.getIcons()::add);
             } catch (IOException exception) {
                 throw new RuntimeException(exception);
             }
diff --git a/src/main/java/jace/JaceUIController.java b/src/main/java/jace/JaceUIController.java
index 7181bd3..778b64c 100644
--- a/src/main/java/jace/JaceUIController.java
+++ b/src/main/java/jace/JaceUIController.java
@@ -3,7 +3,6 @@
  * To change this template file, choose Tools | Templates
  * and open the template in the editor.
  */
-
 package jace;
 
 import com.sun.glass.ui.Application;
@@ -57,7 +56,7 @@ public class JaceUIController {
 
     @FXML
     private AnchorPane rootPane;
-    
+
     @FXML
     private StackPane stackPane;
 
@@ -68,7 +67,7 @@ public class JaceUIController {
     private ImageView appleScreen;
 
     Computer computer;
-    
+
     @FXML
     void initialize() {
         assert rootPane != null : "fx:id=\"rootPane\" was not injected: check your FXML file 'JaceUI.fxml'.";
@@ -80,18 +79,18 @@ public class JaceUIController {
         rootPane.setOnDragEntered(this::processDragEnteredEvent);
         rootPane.setOnDragExited(this::processDragExitedEvent);
     }
-    
+
     public void connectComputer(Computer computer, Stage primaryStage) {
         this.computer = computer;
         appleScreen.setImage(computer.getVideo().getFrameBuffer());
         EventHandler<KeyEvent> keyboardHandler = computer.getKeyboard().getListener();
-        primaryStage.setOnShowing(evt->computer.getKeyboard().resetState());
+        primaryStage.setOnShowing(evt -> computer.getKeyboard().resetState());
         rootPane.setFocusTraversable(true);
         rootPane.setOnKeyPressed(keyboardHandler);
         rootPane.setOnKeyReleased(keyboardHandler);
         rootPane.requestFocus();
     }
-    
+
     private void processDragEnteredEvent(DragEvent evt) {
         MediaEntry media = null;
         if (evt.getDragboard().hasFiles()) {
@@ -115,63 +114,68 @@ public class JaceUIController {
             startDragEvent(media);
         }
     }
-    
+
     private void processDragExitedEvent(DragEvent evt) {
         endDragEvent();
     }
 
-    
     private File getDraggedFile(List<File> files) {
         if (files == null || files.isEmpty()) {
             return null;
         }
         for (File f : files) {
-            if (f.exists()) return f;
+            if (f.exists()) {
+                return f;
+            }
         }
         return null;
     }
 
     HBox drivePanel;
+
     private void startDragEvent(MediaEntry media) {
         List<MediaConsumer> consumers = getMediaConsumers();
         drivePanel = new HBox();
         consumers.stream()
-            .filter((consumer) -> (consumer.isAccepted(media, media.files.get(0))))
-            .forEach((consumer) -> {
-                Label icon = consumer.getIcon();
-                icon.setTextFill(Color.WHITE);
-                icon.setPadding(new Insets(2.0));
-                drivePanel.getChildren().add(icon);
-                icon.setOnDragOver(event -> {
-                    event.acceptTransferModes(TransferMode.ANY);
-                    event.consume();
-                });
-                icon.setOnDragDropped(event -> {
-                    System.out.println("Dropping media on "+icon.getText());
-                    try {
-                        computer.pause();
-                        consumer.insertMedia(media, media.files.get(0));
-                        computer.resume();
-                        event.setDropCompleted(true);
-                        event.consume();
-                    } catch (IOException ex) {
-                        Logger.getLogger(JaceUIController.class.getName()).log(Level.SEVERE, null, ex);
+                .filter((consumer) -> (consumer.isAccepted(media, media.files.get(0))))
+                .forEach((consumer) -> {
+                    Label icon = consumer.getIcon().orElse(null);
+                    if (icon == null) {
+                        return;
                     }
-                    endDragEvent();
+                    icon.setTextFill(Color.WHITE);
+                    icon.setPadding(new Insets(2.0));
+                    drivePanel.getChildren().add(icon);
+                    icon.setOnDragOver(event -> {
+                        event.acceptTransferModes(TransferMode.ANY);
+                        event.consume();
+                    });
+                    icon.setOnDragDropped(event -> {
+                        System.out.println("Dropping media on " + icon.getText());
+                        try {
+                            computer.pause();
+                            consumer.insertMedia(media, media.files.get(0));
+                            computer.resume();
+                            event.setDropCompleted(true);
+                            event.consume();
+                        } catch (IOException ex) {
+                            Logger.getLogger(JaceUIController.class.getName()).log(Level.SEVERE, null, ex);
+                        }
+                        endDragEvent();
+                    });
                 });
-            });
-        stackPane.getChildren().add(drivePanel);        
+        stackPane.getChildren().add(drivePanel);
         drivePanel.setLayoutX(10);
         drivePanel.setLayoutY(10);
     }
-    
+
     private void endDragEvent() {
         stackPane.getChildren().remove(drivePanel);
         drivePanel.getChildren().stream().forEach((n) -> {
             n.setOnDragDropped(null);
         });
     }
-    
+
     private List<MediaConsumer> getMediaConsumers() {
         List<MediaConsumer> consumers = new ArrayList<>();
         for (Optional<Card> card : computer.memory.getAllCards()) {
@@ -181,14 +185,16 @@ public class JaceUIController {
         }
         return consumers;
     }
-    
+
     Map<Label, Long> iconTTL = new ConcurrentHashMap<>();
+
     void addIndicator(Label icon) {
         addIndicator(icon, 250);
     }
+
     void addIndicator(Label icon, long TTL) {
         if (!iconTTL.containsKey(icon)) {
-            Application.invokeLater(()->{
+            Application.invokeLater(() -> {
                 if (!notificationBox.getChildren().contains(icon)) {
                     notificationBox.getChildren().add(icon);
                 }
@@ -198,39 +204,40 @@ public class JaceUIController {
     }
 
     void removeIndicator(Label icon) {
-        Application.invokeLater(()->{
+        Application.invokeLater(() -> {
             notificationBox.getChildren().remove(icon);
             iconTTL.remove(icon);
         });
-    }    
+    }
 
     ScheduledExecutorService notificationExecutor = Executors.newSingleThreadScheduledExecutor();
     ScheduledFuture ttlCleanupTask = null;
+
     private void trackTTL(Label icon, long TTL) {
-        iconTTL.put(icon, System.currentTimeMillis()+TTL);
-        
-        if (ttlCleanupTask == null || ttlCleanupTask.isCancelled()) {        
+        iconTTL.put(icon, System.currentTimeMillis() + TTL);
+
+        if (ttlCleanupTask == null || ttlCleanupTask.isCancelled()) {
             ttlCleanupTask = notificationExecutor.scheduleWithFixedDelay(this::processTTL, 1, 100, TimeUnit.MILLISECONDS);
         }
     }
-    
+
     private void processTTL() {
         Long now = System.currentTimeMillis();
         iconTTL.keySet().stream()
-            .filter((icon) -> (iconTTL.get(icon) <= now))
-            .forEach((icon) -> {
-                removeIndicator(icon);
-            });
+                .filter((icon) -> (iconTTL.get(icon) <= now))
+                .forEach((icon) -> {
+                    removeIndicator(icon);
+                });
         if (iconTTL.isEmpty()) {
             ttlCleanupTask.cancel(true);
             ttlCleanupTask = null;
         }
     }
-    
+
     public void addMouseListener(EventHandler<MouseEvent> handler) {
         appleScreen.addEventHandler(MouseEvent.ANY, handler);
     }
-    
+
     public void removeMouseListener(EventHandler<MouseEvent> handler) {
         appleScreen.removeEventHandler(MouseEvent.ANY, handler);
     }
diff --git a/src/main/java/jace/apple2e/MOS65C02.java b/src/main/java/jace/apple2e/MOS65C02.java
index b19b3cc..09574a4 100644
--- a/src/main/java/jace/apple2e/MOS65C02.java
+++ b/src/main/java/jace/apple2e/MOS65C02.java
@@ -77,12 +77,29 @@ public class MOS65C02 extends CPU {
 
     public MOS65C02(Computer computer) {
         super(computer);
+        clearState();
     }
 
     @Override
     public void reconfigure() {
     }
 
+    @Override
+    public void clearState() {
+        A = 0x0ff;
+        X = 0x0ff;
+        Y = 0x0ff;
+        C = 1;
+        interruptSignalled = false;
+        Z = true;
+        I = true;
+        D = true;
+        B = true;
+        V = true;
+        N = true;
+        STACK = 0xff;
+    }
+    
     public enum OPCODE {
         ADC_IMM(0x0069, COMMAND.ADC, MODE.IMMEDIATE, 2),
         ADC_ZP(0x0065, COMMAND.ADC, MODE.ZEROPAGE, 3),
@@ -369,7 +386,7 @@ public class MOS65C02 extends CPU {
             int pc = cpu.getProgramCounter();
             int address = pc + 2 + cpu.getMemory().read(pc + 1, TYPE.READ_OPERAND, cpu.readAddressTriggersEvent, false);
             // The wait cycles are not added unless the branch actually happens!
-            cpu.setPageBoundaryPenalty((address & 0x00ff00) != (pc & 0x00ff00));
+            cpu.setPageBoundaryPenalty((address & 0x00ff00) != ((pc+2) & 0x00ff00));
             return address;
         }, false),
         IMMEDIATE(2, "#$~1", (cpu) -> cpu.getProgramCounter() + 1),
diff --git a/src/main/java/jace/assembly/AssemblyHandler.java b/src/main/java/jace/assembly/AssemblyHandler.java
index d462d16..5cc12b3 100644
--- a/src/main/java/jace/assembly/AssemblyHandler.java
+++ b/src/main/java/jace/assembly/AssemblyHandler.java
@@ -32,7 +32,11 @@ public class AssemblyHandler implements LanguageHandler<File> {
     public void execute(CompileResult<File> lastResult) {
         if (lastResult.isSuccessful()) {
             try {
-                Emulator.computer.pause();
+                boolean resume = false;
+                if (Emulator.computer.isRunning()) {
+                    resume = true;
+                    Emulator.computer.pause();
+                }
                 RAM memory = Emulator.computer.getMemory();
                 FileInputStream input = new FileInputStream(lastResult.getCompiledAsset());
                 int startLSB = input.read();
@@ -43,7 +47,9 @@ public class AssemblyHandler implements LanguageHandler<File> {
                 while ((next=input.read()) != -1) {
                     memory.write(pos++, (byte) next, false, true);
                 }
-                Emulator.computer.resume();
+                if (resume) {
+                    Emulator.computer.resume();
+                }
             } catch (IOException ex) {
                 Logger.getLogger(AssemblyHandler.class.getName()).log(Level.SEVERE, null, ex);
             }
diff --git a/src/main/java/jace/config/Configuration.java b/src/main/java/jace/config/Configuration.java
index e60459d..277e8dc 100644
--- a/src/main/java/jace/config/Configuration.java
+++ b/src/main/java/jace/config/Configuration.java
@@ -51,6 +51,7 @@ import java.util.logging.Level;
 import java.util.logging.Logger;
 import javafx.collections.ObservableList;
 import javafx.scene.control.TreeItem;
+import javafx.scene.image.Image;
 import javafx.scene.image.ImageView;
 
 /**
@@ -93,8 +94,13 @@ public class Configuration implements Reconfigurable {
         return null;
     }
 
-    public static ImageView getChangedIcon() {
-        return new ImageView(Utility.loadIcon("icon_exclaim.gif"));
+    public static Optional<ImageView> getChangedIcon() {
+        Optional<Image> icon = Utility.loadIcon("icon_exclaim.gif");
+        if (icon.isPresent()) {
+            return Optional.of(new ImageView(icon.get()));
+        } else {
+            return Optional.empty();
+        }
     }
 
     @Override
@@ -251,7 +257,7 @@ public class Configuration implements Reconfigurable {
             if (!changed) {
                 setGraphic(null);
             } else {
-                setGraphic(getChangedIcon());
+                getChangedIcon().ifPresent(this::setGraphic);
             }
         }
     }
diff --git a/src/main/java/jace/core/CPU.java b/src/main/java/jace/core/CPU.java
index aa7bb8b..3718133 100644
--- a/src/main/java/jace/core/CPU.java
+++ b/src/main/java/jace/core/CPU.java
@@ -175,4 +175,6 @@ public abstract class CPU extends Device {
         lastTrace = trace;
         singleTraceEnabled = false;
     }
+
+    abstract public void clearState();
 }
\ No newline at end of file
diff --git a/src/main/java/jace/core/Utility.java b/src/main/java/jace/core/Utility.java
index 63f596b..533be9f 100644
--- a/src/main/java/jace/core/Utility.java
+++ b/src/main/java/jace/core/Utility.java
@@ -31,6 +31,7 @@ import java.util.Comparator;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Optional;
 import java.util.Set;
 import java.util.logging.Level;
 import java.util.logging.Logger;
@@ -280,13 +281,24 @@ public class Utility {
         return result;
     }
 
-    public static Image loadIcon(String filename) {
+    private static boolean isHeadless = false;
+    public static void setHeadlessMode(boolean headless) {
+        isHeadless = headless;
+    }
+    
+    public static Optional<Image> loadIcon(String filename) {
+        if (isHeadless) {
+            return Optional.empty();
+        }
         InputStream stream = Utility.class.getClassLoader().getResourceAsStream("jace/data/" + filename);
-        return new Image(stream);
+        return Optional.of(new Image(stream));
     }
 
-    public static Label loadIconLabel(String filename) {
-        Image img = loadIcon(filename);
+    public static Optional<Label> loadIconLabel(String filename) {
+        if (isHeadless) {
+            return Optional.empty();
+        }
+        Image img = loadIcon(filename).get();
         Label label = new Label() {
             @Override
             public boolean equals(Object obj) {
@@ -309,7 +321,7 @@ public class Utility {
         label.setTextFill(Color.WHITE);
         DropShadow shadow = new DropShadow(5.0, Color.BLACK);
         label.setEffect(shadow);
-        return label;
+        return Optional.of(label);
     }
 
 //    public static void runModalProcess(String title, final Runnable runnable) {
diff --git a/src/main/java/jace/hardware/CardAppleMouse.java b/src/main/java/jace/hardware/CardAppleMouse.java
index fb92860..29f0359 100644
--- a/src/main/java/jace/hardware/CardAppleMouse.java
+++ b/src/main/java/jace/hardware/CardAppleMouse.java
@@ -84,7 +84,7 @@ public class CardAppleMouse extends Card {
     public boolean fullscreenFix = true;
     @ConfigurableField(name = "Blazing Paddles fix", shortName = "bpfix", category = "Mouse", description = "Use different clamping values to make Blazing Paddles work more reliably.")
     public boolean blazingPaddles = false;
-    Label mouseActive = Utility.loadIconLabel("input-mouse.png");
+    Label mouseActive = Utility.loadIconLabel("input-mouse.png").orElse(null);
     public boolean movedSinceLastTick = false;
     public boolean movedSinceLastRead = false;
     
diff --git a/src/main/java/jace/hardware/CardDiskII.java b/src/main/java/jace/hardware/CardDiskII.java
index d023fb8..737ecc3 100644
--- a/src/main/java/jace/hardware/CardDiskII.java
+++ b/src/main/java/jace/hardware/CardDiskII.java
@@ -104,13 +104,13 @@ public class CardDiskII extends Card implements Reconfigurable, MediaConsumerPar
             case 0x8:
                 // drive off
                 currentDrive.setOn(false);
-                EmulatorUILogic.removeIndicator(this, currentDrive.getIcon());
+                currentDrive.getIcon().ifPresent(icon->EmulatorUILogic.removeIndicator(this, icon));
                 break;
 
             case 0x9:
                 // drive on
                 currentDrive.setOn(true);
-                EmulatorUILogic.addIndicator(this, currentDrive.getIcon());
+                currentDrive.getIcon().ifPresent(icon->EmulatorUILogic.addIndicator(this, icon));
                 break;
 
             case 0xA:
@@ -128,7 +128,7 @@ public class CardDiskII extends Card implements Reconfigurable, MediaConsumerPar
                 currentDrive.write();
                 e.setNewValue(currentDrive.readLatch());
                 if (currentDrive.isOn()) {
-                    EmulatorUILogic.addIndicator(this, currentDrive.getIcon());
+                    currentDrive.getIcon().ifPresent(icon->EmulatorUILogic.removeIndicator(this, icon));
                 }
                 break;
             case 0xF:
@@ -226,8 +226,8 @@ public class CardDiskII extends Card implements Reconfigurable, MediaConsumerPar
     @Override
     public void setSlot(int slot) {
         super.setSlot(slot);
-        drive1.getIcon().setText("S" + slot + "D1");
-        drive2.getIcon().setText("S" + slot + "D2");
+        drive1.getIcon().ifPresent(icon->icon.setText("S" + slot + "D1"));
+        drive2.getIcon().ifPresent(icon->icon.setText("S" + slot + "D2"));
     }
 
     @Override
diff --git a/src/main/java/jace/hardware/CardRamFactor.java b/src/main/java/jace/hardware/CardRamFactor.java
index f6ba902..c213107 100644
--- a/src/main/java/jace/hardware/CardRamFactor.java
+++ b/src/main/java/jace/hardware/CardRamFactor.java
@@ -24,11 +24,12 @@ import jace.core.Card;
 import jace.core.Computer;
 import jace.core.RAMEvent;
 import jace.core.RAMEvent.TYPE;
-import jace.state.Stateful;
 import jace.core.Utility;
+import jace.state.Stateful;
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.Arrays;
+import java.util.Optional;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 import javafx.scene.control.Label;
@@ -62,10 +63,10 @@ public class CardRamFactor extends Card {
     public String getDeviceName() {
         return "RamFactor";
     }
-    Label indicator;
+    Optional<Label> indicator;
     public CardRamFactor(Computer computer) {
         super(computer);
-        indicator=Utility.loadIconLabel("ram.png");
+        indicator = Utility.loadIconLabel("ram.png");
         try {
             loadRom("jace/data/RAMFactor14.rom");
         } catch (IOException ex) {
@@ -204,7 +205,9 @@ public class CardRamFactor extends Card {
     @Override
     public void setSlot(int slot) {
         super.setSlot(slot);
-        indicator.setText("Slot "+getSlot());
+        indicator.ifPresent(icon->
+            icon.setText("Slot "+getSlot())
+        );
         // Rom has different images for each slot
         updateFirmwareMemory();
     }
diff --git a/src/main/java/jace/hardware/CardSSC.java b/src/main/java/jace/hardware/CardSSC.java
index 4c086ab..67014a4 100644
--- a/src/main/java/jace/hardware/CardSSC.java
+++ b/src/main/java/jace/hardware/CardSSC.java
@@ -116,8 +116,10 @@ public class CardSSC extends Card implements Reconfigurable {
             Logger.getLogger(CardSSC.class.getName()).log(Level.SEVERE, null, ex);
         }
         super.setSlot(slot);
-        activityIndicator = Utility.loadIconLabel("network-wired.png");
-        activityIndicator.setText("Slot " + slot);
+        Utility.loadIconLabel("network-wired.png").ifPresent(icon->{
+            activityIndicator = icon;
+            activityIndicator.setText("Slot " + slot);
+        });
     }
 
     boolean newInputAvailable = false;
diff --git a/src/main/java/jace/hardware/CardThunderclock.java b/src/main/java/jace/hardware/CardThunderclock.java
index cac1584..5419acb 100644
--- a/src/main/java/jace/hardware/CardThunderclock.java
+++ b/src/main/java/jace/hardware/CardThunderclock.java
@@ -32,6 +32,7 @@ import jace.core.Utility;
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.Calendar;
+import java.util.Optional;
 import java.util.Stack;
 import java.util.logging.Level;
 import java.util.logging.Logger;
@@ -50,8 +51,7 @@ import javafx.scene.control.Label;
 @Name("ThunderClock Plus")
 public class CardThunderclock extends Card {
 
-    Label clockIcon;
-    Label clockFixIcon;
+    Optional<Label> clockIcon;
     long lastShownIcon = -1;
     // Only mention that the clock is read if it hasn't been checked for over 30 seconds
     // This is to avoid showing it all the time in programs that poll it constantly
@@ -152,12 +152,14 @@ public class CardThunderclock extends Card {
                     performProdosPatch(computer);
                 }
                 getTime();
-                clockIcon.setText("Slot " + getSlot());
-                long now = System.currentTimeMillis();
-                if ((now - lastShownIcon) > MIN_WAIT) {
-                    EmulatorUILogic.addIndicator(this, clockIcon, 3000);
-                }
-                lastShownIcon = now;
+                clockIcon.ifPresent(icon->{
+                    icon.setText("Slot " + getSlot());
+                    long now = System.currentTimeMillis();
+                    if ((now - lastShownIcon) > MIN_WAIT) {
+                        EmulatorUILogic.addIndicator(this, icon, 3000);
+                    }
+                    lastShownIcon = now;
+                });
             }
             shiftMode = isShift;
         }
@@ -324,8 +326,9 @@ public class CardThunderclock extends Card {
         ram.writeByte(patchLoc + 1, (byte) year);
         ram.writeByte(patchLoc + 2, (byte) MOS65C02.OPCODE.NOP.getCode());
         ram.writeByte(patchLoc + 3, (byte) MOS65C02.OPCODE.NOP.getCode());
-        Label clockFixIcon = Utility.loadIconLabel("clock_fix.png");
-        clockFixIcon.setText("Fixed");
-        EmulatorUILogic.addIndicator(CardThunderclock.class, clockFixIcon, 4000);
+        Utility.loadIconLabel("clock_fix.png").ifPresent(clockFixIcon->{
+            clockFixIcon.setText("Fixed");
+            EmulatorUILogic.addIndicator(CardThunderclock.class, clockFixIcon, 4000);
+        });
     }
 }
\ No newline at end of file
diff --git a/src/main/java/jace/hardware/DiskIIDrive.java b/src/main/java/jace/hardware/DiskIIDrive.java
index 1494b1c..b411619 100644
--- a/src/main/java/jace/hardware/DiskIIDrive.java
+++ b/src/main/java/jace/hardware/DiskIIDrive.java
@@ -27,6 +27,7 @@ import jace.state.Stateful;
 import java.io.File;
 import java.io.IOException;
 import java.util.HashSet;
+import java.util.Optional;
 import java.util.Set;
 import java.util.concurrent.locks.LockSupport;
 import javafx.scene.control.Label;
@@ -225,20 +226,19 @@ public class DiskIIDrive implements MediaConsumer {
 
     void insertDisk(File diskPath) throws IOException {
         disk = new FloppyDisk(diskPath, computer);
-        System.out.println("Inserting "+diskPath.getPath()+" into "+getIcon().getText());
         dirtyTracks = new HashSet<>();
         // Emulator state has changed significantly, reset state manager
         StateManager.getInstance(computer).invalidate();
     }
-    private Label icon;
+    private Optional<Label> icon;
 
     @Override
-    public Label getIcon() {
+    public Optional<Label> getIcon() {
         return icon;
     }
 
     @Override
-    public void setIcon(Label i) {
+    public void setIcon(Optional<Label> i) {
         icon = i;
     }
     private MediaEntry currentMediaEntry;
diff --git a/src/main/java/jace/hardware/NoSlotClock.java b/src/main/java/jace/hardware/NoSlotClock.java
index 7de0bd6..111c492 100644
--- a/src/main/java/jace/hardware/NoSlotClock.java
+++ b/src/main/java/jace/hardware/NoSlotClock.java
@@ -9,6 +9,7 @@ import jace.core.RAMEvent;
 import jace.core.RAMListener;
 import jace.core.Utility;
 import java.util.Calendar;
+import java.util.Optional;
 import javafx.scene.control.Label;
 
 /**
@@ -28,7 +29,7 @@ public class NoSlotClock extends Device {
     public boolean writeEnabled = false;
     @ConfigurableField(category = "Clock", name = "Patch Prodos", description = "If enabled, prodos clock routines will be patched directly", defaultValue = "false")
     public boolean patchProdosClock = false;
-    Label clockIcon;
+    Optional<Label> clockIcon;
 
     private final RAMListener listener = new RAMListener(RAMEvent.TYPE.ANY, RAMEvent.SCOPE.RANGE, RAMEvent.VALUE.ANY) {
         @Override
@@ -89,7 +90,7 @@ public class NoSlotClock extends Device {
     public NoSlotClock(Computer computer) {
         super(computer);
         this.clockIcon = Utility.loadIconLabel("clock.png");
-        this.clockIcon.setText("No Slot Clock");
+        this.clockIcon.ifPresent(icon -> icon.setText("No Slot Clock"));
     }
 
     @Override
@@ -133,7 +134,8 @@ public class NoSlotClock extends Device {
         storeBCD(now.get(Calendar.MONTH) + 1, 6);
         storeBCD(now.get(Calendar.YEAR) % 100, 7);
         clockActive = true;
-        EmulatorUILogic.addIndicator(this, clockIcon, 1000);
+        clockIcon.ifPresent(icon
+                -> EmulatorUILogic.addIndicator(this, icon, 1000));
         if (patchProdosClock) {
             CardThunderclock.performProdosPatch(computer);
         }
diff --git a/src/main/java/jace/hardware/massStorage/CardMassStorage.java b/src/main/java/jace/hardware/massStorage/CardMassStorage.java
index a8b5bdc..20beab2 100644
--- a/src/main/java/jace/hardware/massStorage/CardMassStorage.java
+++ b/src/main/java/jace/hardware/massStorage/CardMassStorage.java
@@ -59,8 +59,8 @@ public class CardMassStorage extends Card implements MediaConsumerParent {
     @Override
     public void setSlot(int slot) {
         super.setSlot(slot);
-        drive1.getIcon().setText("S" + getSlot() + "D1");
-        drive2.getIcon().setText("S" + getSlot() + "D2");
+        drive1.getIcon().ifPresent(icon->icon.setText("S" + getSlot() + "D1"));
+        drive2.getIcon().ifPresent(icon->icon.setText("S" + getSlot() + "D2"));
     }
 
     @Override
diff --git a/src/main/java/jace/hardware/massStorage/MassStorageDrive.java b/src/main/java/jace/hardware/massStorage/MassStorageDrive.java
index 34892c9..a9afcb7 100644
--- a/src/main/java/jace/hardware/massStorage/MassStorageDrive.java
+++ b/src/main/java/jace/hardware/massStorage/MassStorageDrive.java
@@ -23,6 +23,7 @@ import jace.library.MediaEntry;
 import jace.library.MediaEntry.MediaFile;
 import java.io.File;
 import java.io.IOException;
+import java.util.Optional;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 import javafx.scene.control.Label;
@@ -33,10 +34,10 @@ import javafx.scene.control.Label;
  */
 public class MassStorageDrive implements MediaConsumer {
     IDisk disk = null;
-    Label icon = null;
+    Optional<Label> icon = null;
     
     @Override
-    public Label getIcon() {
+    public Optional<Label> getIcon() {
         return icon;
     }
 
@@ -45,7 +46,7 @@ public class MassStorageDrive implements MediaConsumer {
      * @param i
      */
     @Override
-    public void setIcon(Label i) {
+    public void setIcon(Optional<Label> i) {
         icon = i;
     }
 
diff --git a/src/main/java/jace/ide/HeadlessProgram.java b/src/main/java/jace/ide/HeadlessProgram.java
new file mode 100644
index 0000000..f63f2be
--- /dev/null
+++ b/src/main/java/jace/ide/HeadlessProgram.java
@@ -0,0 +1,50 @@
+/*
+ * Copyright 2016 Brendan Robert
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package jace.ide;
+
+import java.util.Collections;
+import java.util.Map;
+
+/**
+ * This is a program that is intended to be defined and executed outside of a IDE session
+ * @author blurry
+ */
+public class HeadlessProgram extends Program {    
+    public HeadlessProgram(DocumentType type) {
+        super(type, Collections.EMPTY_MAP);
+    }
+
+    String program;
+    @Override
+    public String getValue() {
+        return program;
+    }
+
+    @Override
+    public void setValue(String value) {
+        program = value;
+    }
+
+    public HeadlessProgram() {
+        super(null, null);
+    }
+
+    CompileResult lastResult = null;
+    @Override
+    protected void manageCompileResult(CompileResult lastResult) {
+        this.lastResult = lastResult;
+    }
+}
diff --git a/src/main/java/jace/ide/Program.java b/src/main/java/jace/ide/Program.java
index 6695929..63e372c 100644
--- a/src/main/java/jace/ide/Program.java
+++ b/src/main/java/jace/ide/Program.java
@@ -231,7 +231,7 @@ public class Program {
         getHandler().clean(lastResult);
     }
 
-    private void manageCompileResult(CompileResult lastResult) {
+    protected void manageCompileResult(CompileResult lastResult) {
         editor.getEngine().executeScript("clearHighlights()");
         lastResult.getWarnings().forEach((line, message)
                 -> editor.getEngine().executeScript("highlightLine(" + line + ",false,\"" + escapeString(message) + "\");")
diff --git a/src/main/java/jace/library/DiskType.java b/src/main/java/jace/library/DiskType.java
index b8b517d..5d36e62 100644
--- a/src/main/java/jace/library/DiskType.java
+++ b/src/main/java/jace/library/DiskType.java
@@ -21,6 +21,7 @@ package jace.library;
 import jace.core.Utility;
 import jace.hardware.FloppyDisk;
 import java.io.File;
+import java.util.Optional;
 import javafx.scene.image.Image;
 
 /**
@@ -40,7 +41,7 @@ public enum DiskType {
     public boolean isProdosOrdered = false;
     public boolean is140kb = false;
     public String description;
-    public Image diskIcon;
+    public Optional<Image> diskIcon;
     DiskType(String desc, boolean is140, boolean po, String iconPath) {
         description = desc;
         is140kb = is140;
diff --git a/src/main/java/jace/library/MediaConsumer.java b/src/main/java/jace/library/MediaConsumer.java
index d790041..b1907fd 100644
--- a/src/main/java/jace/library/MediaConsumer.java
+++ b/src/main/java/jace/library/MediaConsumer.java
@@ -20,6 +20,7 @@ package jace.library;
 
 import jace.library.MediaEntry.MediaFile;
 import java.io.IOException;
+import java.util.Optional;
 import javafx.scene.control.Label;
 
 /**
@@ -27,8 +28,8 @@ import javafx.scene.control.Label;
  * @author brobert
  */
 public interface MediaConsumer {
-    public Label getIcon();
-    public void setIcon(Label i);
+    public Optional<Label> getIcon();
+    public void setIcon(Optional<Label> i);
     public void insertMedia(MediaEntry e, MediaFile f) throws IOException;
     public MediaEntry getMediaEntry();
     public MediaFile getMediaFile();
diff --git a/src/test/java/jace/cpu/Basic6502FuncationalityTest.java b/src/test/java/jace/cpu/Basic6502FuncationalityTest.java
new file mode 100644
index 0000000..2abbd55
--- /dev/null
+++ b/src/test/java/jace/cpu/Basic6502FuncationalityTest.java
@@ -0,0 +1,90 @@
+/*
+ * Copyright 2016 Brendan Robert
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package jace.cpu;
+
+import jace.Emulator;
+import jace.apple2e.Apple2e;
+import jace.apple2e.MOS65C02;
+import jace.core.Computer;
+import jace.core.RAM;
+import jace.core.Utility;
+import jace.ide.HeadlessProgram;
+import jace.ide.Program;
+import java.util.Collections;
+import org.junit.After;
+import org.junit.AfterClass;
+import static org.junit.Assert.*;
+import org.junit.Before;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+/**
+ * Basic test functionality to assert correct 6502 decode and execution.
+ *
+ * @author blurry
+ */
+public class Basic6502FuncationalityTest {
+
+    static Computer computer;
+    static MOS65C02 cpu;
+    static RAM ram;
+
+    @BeforeClass
+    public static void setupClass() {
+        Utility.setHeadlessMode(true);
+        computer = new Apple2e();
+        cpu = (MOS65C02) computer.getCpu();
+        ram = computer.getMemory();
+        Emulator.computer = (Apple2e) computer;
+    }
+
+    @AfterClass
+    public static void teardownClass() {
+        computer.deactivate();
+    }
+
+    @Before
+    public void setup() {
+        for (int i = 0; i < 1024; i++) {
+            ram.write(i, (byte) 0, false, false);
+        }
+        cpu.setProgramCounter(0);
+        cpu.setWaitCycles(0);
+        cpu.clearState();
+    }
+
+    @After
+    public void teardown() {
+
+    }
+
+    @Test
+    public void testAdditionNonDecimal() {
+        cpu.A = 0;
+        cpu.D = false;
+        assemble(" adc #1");
+        assertEquals("Nothing should change yet", 0, cpu.A);
+        cpu.tick();
+        assertEquals("0+1 = 1", 1, cpu.A);        
+        assertFalse("Result is not zero", cpu.Z);
+    }
+
+    private void assemble(String code) {
+        HeadlessProgram program = new HeadlessProgram(Program.DocumentType.assembly);
+        program.setValue("*=0\n"+code+"\n BRK");
+        program.execute();
+    }
+}
diff --git a/src/test/java/jace/ide/ApplesoftTest.java b/src/test/java/jace/ide/ApplesoftTest.java
index c2af516..c701a40 100644
--- a/src/test/java/jace/ide/ApplesoftTest.java
+++ b/src/test/java/jace/ide/ApplesoftTest.java
@@ -54,14 +54,14 @@ public class ApplesoftTest {
     }
     
     @Test
-    public void deserializeBinary() {
+    public void deserializeBinaryTest() {
         ApplesoftProgram program = ApplesoftProgram.fromBinary(Lists.newArrayList(lemonadeStandBinary), 0x0801);
         assertNotNull(program);
         assertNotSame("", program.toString());
     }
     
     @Test
-    public void roundTripStringComparison() {
+    public void roundTripStringComparisonTest() {
         ApplesoftProgram program = ApplesoftProgram.fromBinary(Lists.newArrayList(lemonadeStandBinary), 0x0801);
         String serialized = program.toString();
         ApplesoftProgram deserialized = ApplesoftProgram.fromString(serialized);