diff --git a/qtBuildSystem/Mu/Mu.pro b/qtBuildSystem/Mu/Mu.pro
index 8f546d0..d1fb7bc 100644
--- a/qtBuildSystem/Mu/Mu.pro
+++ b/qtBuildSystem/Mu/Mu.pro
@@ -18,7 +18,7 @@ TEMPLATE = app
 DEFINES += QT_DEPRECATED_WARNINGS
 
 CONFIG(debug, debug|release){
-    DEFINES += EMU_DEBUG
+    DEFINES += EMU_DEBUG EMU_OPCODE_LEVEL_DEBUG
 }
 
 # You can also make your code fail to compile if you use deprecated APIs.
diff --git a/qtBuildSystem/Mu/main.cpp b/qtBuildSystem/Mu/main.cpp
index 26d2721..4222042 100644
--- a/qtBuildSystem/Mu/main.cpp
+++ b/qtBuildSystem/Mu/main.cpp
@@ -3,12 +3,12 @@
 
 int main(int argc, char *argv[])
 {
-	QApplication a(argc, argv);
-	MainWindow w;
+   QApplication a(argc, argv);
+   MainWindow w;
 
-	a.setOrganizationDomain("meepingsnesroms.github.com");
-	a.setApplicationName("Mu");
-	w.show();
+   a.setOrganizationDomain("meepingsnesroms.github.com");
+   a.setApplicationName("Mu");
+   w.show();
 
-	return a.exec();
+   return a.exec();
 }
diff --git a/qtBuildSystem/Mu/mainwindow.cpp b/qtBuildSystem/Mu/mainwindow.cpp
index c1e986b..71d57e7 100644
--- a/qtBuildSystem/Mu/mainwindow.cpp
+++ b/qtBuildSystem/Mu/mainwindow.cpp
@@ -31,244 +31,252 @@ static uint8_t romBuffer[ROM_SIZE];
 
 
 void popupErrorDialog(std::string error){
-    //add error dialog code
+   //add error dialog code
 }
 
 uint8_t* getFileBuffer(std::string filePath, size_t& size, uint32_t& error){
-    uint8_t* rawData = NULL;
-    if(filePath != ""){
-        struct stat st;
-        int doesntExist = stat(filePath.c_str(), &st);
-        if(doesntExist == 0 && st.st_size){
-            FILE* dataFile = fopen(filePath.c_str(), "rb");
-            if(dataFile != NULL){
-                rawData = new (std::nothrow) uint8_t[st.st_size];
-                if(rawData){
-                    size_t bytesRead = fread(rawData, 1, st.st_size, dataFile);
-                    if(bytesRead == (size_t)st.st_size){
-                        size = bytesRead;
-                        error = FRONTEND_ERR_NONE;
-                    }
-                    else{
-                        error = FRONTEND_FILE_UNFINISHED;
-                    }
-                }
-                else{
-                    error = FRONTEND_OUT_OF_MEMORY;
-                }
-                fclose(dataFile);
+   uint8_t* rawData = NULL;
+   if(filePath != ""){
+      struct stat st;
+      int doesntExist = stat(filePath.c_str(), &st);
+      if(doesntExist == 0 && st.st_size){
+         FILE* dataFile = fopen(filePath.c_str(), "rb");
+         if(dataFile != NULL){
+            rawData = new (std::nothrow) uint8_t[st.st_size];
+            if(rawData){
+               size_t bytesRead = fread(rawData, 1, st.st_size, dataFile);
+               if(bytesRead == (size_t)st.st_size){
+                  size = bytesRead;
+                  error = FRONTEND_ERR_NONE;
+               }
+               else{
+                  error = FRONTEND_FILE_UNFINISHED;
+               }
             }
             else{
-                error = FRONTEND_FILE_PROTECTED;
+               error = FRONTEND_OUT_OF_MEMORY;
             }
-        }
-        else{
-            error = FRONTEND_FILE_DOESNT_EXIST;
-        }
-    }
-    else{
-        error = FRONTEND_FILE_EMPTY_PATH;
-    }
+            fclose(dataFile);
+         }
+         else{
+            error = FRONTEND_FILE_PROTECTED;
+         }
+      }
+      else{
+         error = FRONTEND_FILE_DOESNT_EXIST;
+      }
+   }
+   else{
+      error = FRONTEND_FILE_EMPTY_PATH;
+   }
 
-    if(error != FRONTEND_ERR_NONE){
-        if(rawData)
-            delete[] rawData;
-        rawData = NULL;
-        size = 0;
-    }
+   if(error != FRONTEND_ERR_NONE){
+      if(rawData)
+         delete[] rawData;
+      rawData = NULL;
+      size = 0;
+   }
 
-    return rawData;
+   return rawData;
 }
 
 
 MainWindow::MainWindow(QWidget* parent) :
-    QMainWindow(parent),
-    ui(new Ui::MainWindow){
-    ui->setupUi(this);
-    emuOn = false;
-    emuInited = false;
-    screenWidth = 160;
-    screenHeight = 160 + 60;
+   QMainWindow(parent),
+   ui(new Ui::MainWindow){
+   ui->setupUi(this);
+   emuOn = false;
+   emuInited = false;
+   screenWidth = 160;
+   screenHeight = 160 + 60;
 
-    loadRom();
+   loadRom();
 
-    ui->ctrlBtn->setText("Start");
+   ui->ctrlBtn->setText("Start");
 
-    refreshDisplay = new QTimer(this);
-    connect(refreshDisplay, SIGNAL(timeout()), this, SLOT(updateDisplay()));
-    //update display every 16.67 miliseconds = 60*second
-    refreshDisplay->start(16);
+   refreshDisplay = new QTimer(this);
+   connect(refreshDisplay, SIGNAL(timeout()), this, SLOT(updateDisplay()));
+   //update display every 16.67 miliseconds = 60*second
+   refreshDisplay->start(16);
 }
 
 MainWindow::~MainWindow(){
-    emuMutex.lock();
-    emulatorExit();
-    emuMutex.unlock();
-    delete ui;
+   emuMutex.lock();
+   emulatorExit();
+   emuMutex.unlock();
+   delete ui;
 }
 
 
 void MainWindow::loadRom(){
-    std::string rom = settings.value("romPath", "").toString().toStdString();
-    if(rom == ""){
-        //keep the selector open until a valid file is picked
-        while(settings.value("romPath", "").toString().toStdString() == "")
-            selectRom();
-    }
+   std::string rom = settings.value("romPath", "").toString().toStdString();
+   if(rom == ""){
+      //keep the selector open until a valid file is picked
+      while(settings.value("romPath", "").toString().toStdString() == "")
+         selectRom();
+   }
 
-    uint32_t error;
-    size_t size;
-    uint8_t* romData = getFileBuffer(rom, size, error);
-    if(romData){
-        size_t romSize = size < ROM_SIZE ? size : ROM_SIZE;
-        memcpy(romBuffer, romData, romSize);
-        if(romSize < ROM_SIZE)
-            memset(romBuffer + romSize, 0x00, ROM_SIZE - romSize);
-        delete[] romData;
-    }
+   uint32_t error;
+   size_t size;
+   uint8_t* romData = getFileBuffer(rom, size, error);
+   if(romData){
+      size_t romSize = size < ROM_SIZE ? size : ROM_SIZE;
+      memcpy(romBuffer, romData, romSize);
+      if(romSize < ROM_SIZE)
+         memset(romBuffer + romSize, 0x00, ROM_SIZE - romSize);
+      delete[] romData;
+   }
 
-    if(error != FRONTEND_ERR_NONE){
-        popupErrorDialog("Could not open ROM file");
-    }
+   if(error != FRONTEND_ERR_NONE){
+      popupErrorDialog("Could not open ROM file");
+   }
 }
 
 void MainWindow::selectRom(){
-    std::string rom = QFileDialog::getOpenFileName(this, "Palm OS ROM (palmos41-en-m515.rom)", QDir::root().path(), 0).toStdString();
-    uint32_t error;
-    size_t size;
-    uint8_t* romData = getFileBuffer(rom, size, error);
-    if(romData){
-        //valid file
-        settings.setValue("romPath", QString::fromStdString(rom));
-        delete[] romData;
-    }
+   std::string rom = QFileDialog::getOpenFileName(this, "Palm OS ROM (palmos41-en-m515.rom)", QDir::root().path(), 0).toStdString();
+   uint32_t error;
+   size_t size;
+   uint8_t* romData = getFileBuffer(rom, size, error);
+   if(romData){
+      //valid file
+      settings.setValue("romPath", QString::fromStdString(rom));
+      delete[] romData;
+   }
 
 
-    if(error != FRONTEND_ERR_NONE){
-        popupErrorDialog("Could not open ROM file");
-    }
+   if(error != FRONTEND_ERR_NONE){
+      popupErrorDialog("Could not open ROM file");
+   }
 }
 
 void MainWindow::on_install_pressed(){
-    std::string app = QFileDialog::getOpenFileName(this, "Open Prc/Pdb/Pqa", QDir::root().path(), 0).toStdString();
-    uint32_t error;
-    size_t size;
-    uint8_t* appData = getFileBuffer(app, size, error);
-    if(appData){
-        error = emulatorInstallPrcPdb(appData, size);
-        delete[] appData;
-    }
+   std::string app = QFileDialog::getOpenFileName(this, "Open Prc/Pdb/Pqa", QDir::root().path(), 0).toStdString();
+   uint32_t error;
+   size_t size;
+   uint8_t* appData = getFileBuffer(app, size, error);
+   if(appData){
+      error = emulatorInstallPrcPdb(appData, size);
+      delete[] appData;
+   }
 
-    if(error != FRONTEND_ERR_NONE){
-        popupErrorDialog("Could not install app");
-    }
+   if(error != FRONTEND_ERR_NONE)
+      popupErrorDialog("Could not install app");
 }
 
 //display
 void MainWindow::updateDisplay(){
-    if(emuOn){
-        if(emuMutex.try_lock()){
-            emulateFrame();
-            video = QImage((unsigned char*)palmFramebuffer, screenWidth, screenHeight, QImage::Format_RGB16);//16 bit
-            ui->display->setPixmap(QPixmap::fromImage(video).scaled(ui->display->size(), Qt::KeepAspectRatio, Qt::SmoothTransformation));
-            ui->display->update();
-            emuMutex.unlock();
-        }
-    }
+   if(emuOn){
+      if(emuMutex.try_lock()){
+#ifdef EMU_DEBUG
+         if(emulateUntilDebugEventOrFrameEnd()){
+            //debug event occured
+            emuOn = false;
+            ui->ctrlBtn->setText("Resume");
+         }
+#else
+         emulateFrame();
+#endif
+
+         video = QImage((unsigned char*)palmFramebuffer, screenWidth, screenHeight, QImage::Format_RGB16);//16 bit
+         ui->display->setPixmap(QPixmap::fromImage(video).scaled(ui->display->size(), Qt::KeepAspectRatio, Qt::SmoothTransformation));
+         ui->display->update();
+         emuMutex.unlock();
+      }
+   }
 }
 
 void MainWindow::on_display_destroyed(){
-    //do nothing
+   //do nothing
 }
 
 //palm buttons
 void MainWindow::on_power_pressed(){
-    palmInput.buttonPower = true;
+   palmInput.buttonPower = true;
 }
 
 void MainWindow::on_power_released(){
-    palmInput.buttonPower = false;
+   palmInput.buttonPower = false;
 }
 
 void MainWindow::on_calender_pressed(){
-    palmInput.buttonCalender = true;
+   palmInput.buttonCalender = true;
 }
 
 void MainWindow::on_calender_released(){
-    palmInput.buttonCalender = false;
+   palmInput.buttonCalender = false;
 }
 
 void MainWindow::on_addressBook_pressed(){
-    palmInput.buttonAddress = true;
+   palmInput.buttonAddress = true;
 }
 
 void MainWindow::on_addressBook_released(){
-    palmInput.buttonAddress = false;
+   palmInput.buttonAddress = false;
 }
 
 void MainWindow::on_todo_pressed(){
-    palmInput.buttonTodo = true;
+   palmInput.buttonTodo = true;
 }
 
 void MainWindow::on_todo_released(){
-    palmInput.buttonTodo = false;
+   palmInput.buttonTodo = false;
 }
 
 void MainWindow::on_notes_pressed(){
-    palmInput.buttonNotes = true;
+   palmInput.buttonNotes = true;
 }
 
 void MainWindow::on_notes_released(){
-    palmInput.buttonNotes = false;
+   palmInput.buttonNotes = false;
 }
 
 //ui buttons
 void MainWindow::on_mainLeft_clicked(){
-    ui->controlPanel->setCurrentWidget(ui->controlPanel->widget(2));
+   ui->controlPanel->setCurrentWidget(ui->controlPanel->widget(2));
 }
 
 void MainWindow::on_mainRight_clicked(){
-    ui->controlPanel->setCurrentWidget(ui->controlPanel->widget(1));
+   ui->controlPanel->setCurrentWidget(ui->controlPanel->widget(1));
 }
 
 void MainWindow::on_settingsLeft_clicked(){
-    ui->controlPanel->setCurrentWidget(ui->controlPanel->widget(0));
+   ui->controlPanel->setCurrentWidget(ui->controlPanel->widget(0));
 }
 
 void MainWindow::on_settingsRight_clicked(){
-    ui->controlPanel->setCurrentWidget(ui->controlPanel->widget(2));
+   ui->controlPanel->setCurrentWidget(ui->controlPanel->widget(2));
 }
 
 void MainWindow::on_joyLeft_clicked(){
-    ui->controlPanel->setCurrentWidget(ui->controlPanel->widget(1));
+   ui->controlPanel->setCurrentWidget(ui->controlPanel->widget(1));
 }
 
 void MainWindow::on_joyRight_clicked(){
-    ui->controlPanel->setCurrentWidget(ui->controlPanel->widget(0));
+   ui->controlPanel->setCurrentWidget(ui->controlPanel->widget(0));
 }
 
 void MainWindow::on_settings_clicked(){
-    //setprocess(SETUP);
+   //setprocess(SETUP);
 }
 
 //emu control
 void MainWindow::on_ctrlBtn_clicked()
 {
-    emuMutex.lock();
-    if(!emuOn && !emuInited){
-        //start emu
-        emulatorInit(romBuffer, NULL/*bootloader*/, ACCURATE);
-        emuInited = true;
-        emuOn = true;
-        ui->ctrlBtn->setText("Pause");
-    }
-    else if(emuOn){
-        emuOn = false;
-        ui->ctrlBtn->setText("Resume");
-    }
-    else if(!emuOn){
-        emuOn = true;
-        ui->ctrlBtn->setText("Pause");
-    }
-    emuMutex.unlock();
+   emuMutex.lock();
+   if(!emuOn && !emuInited){
+      //start emu
+      emulatorInit(romBuffer, NULL/*bootloader*/, ACCURATE);
+      emuInited = true;
+      emuOn = true;
+      ui->ctrlBtn->setText("Pause");
+   }
+   else if(emuOn){
+      emuOn = false;
+      ui->ctrlBtn->setText("Resume");
+   }
+   else if(!emuOn){
+      emuOn = true;
+      ui->ctrlBtn->setText("Pause");
+   }
+   emuMutex.unlock();
 }
diff --git a/qtBuildSystem/Mu/mainwindow.h b/qtBuildSystem/Mu/mainwindow.h
index 69960ac..7ead064 100644
--- a/qtBuildSystem/Mu/mainwindow.h
+++ b/qtBuildSystem/Mu/mainwindow.h
@@ -8,14 +8,14 @@ extern uint32_t screenWidth;
 extern uint32_t screenHeight;
 
 enum{
-    FRONTEND_ERR_NONE,
-    FRONTEND_FILE_DOESNT_EXIST,
-    FRONTEND_FILE_EMPTY_PATH,
-    FRONTEND_FILE_UNFINISHED,
-    FRONTEND_FILE_MODIFYED,
-    FRONTEND_FILE_INVALID_TYPE,
-    FRONTEND_FILE_PROTECTED,
-    FRONTEND_OUT_OF_MEMORY
+   FRONTEND_ERR_NONE,
+   FRONTEND_FILE_DOESNT_EXIST,
+   FRONTEND_FILE_EMPTY_PATH,
+   FRONTEND_FILE_UNFINISHED,
+   FRONTEND_FILE_MODIFYED,
+   FRONTEND_FILE_INVALID_TYPE,
+   FRONTEND_FILE_PROTECTED,
+   FRONTEND_OUT_OF_MEMORY
 };
 
 namespace Ui {
@@ -24,44 +24,44 @@ class MainWindow;
 
 class MainWindow : public QMainWindow
 {
-    Q_OBJECT
+   Q_OBJECT
 
 public:
-    explicit MainWindow(QWidget *parent = 0);
-    ~MainWindow();
+   explicit MainWindow(QWidget *parent = 0);
+   ~MainWindow();
 
 private slots:
-    void loadRom();
-    void selectRom();
-    void on_install_pressed();
+   void loadRom();
+   void selectRom();
+   void on_install_pressed();
 
-    //display
-    void updateDisplay();
-    void on_display_destroyed();
+   //display
+   void updateDisplay();
+   void on_display_destroyed();
 
-    //palm buttons
-    void on_power_pressed();
-    void on_power_released();
-    void on_calender_pressed();
-    void on_calender_released();
-    void on_addressBook_pressed();
-    void on_addressBook_released();
-    void on_todo_pressed();
-    void on_todo_released();
-    void on_notes_pressed();
-    void on_notes_released();
+   //palm buttons
+   void on_power_pressed();
+   void on_power_released();
+   void on_calender_pressed();
+   void on_calender_released();
+   void on_addressBook_pressed();
+   void on_addressBook_released();
+   void on_todo_pressed();
+   void on_todo_released();
+   void on_notes_pressed();
+   void on_notes_released();
 
-    //ui buttons
-    void on_mainLeft_clicked();
-    void on_mainRight_clicked();
-    void on_settingsLeft_clicked();
-    void on_settingsRight_clicked();
-    void on_joyLeft_clicked();
-    void on_joyRight_clicked();
-    void on_settings_clicked();
+   //ui buttons
+   void on_mainLeft_clicked();
+   void on_mainRight_clicked();
+   void on_settingsLeft_clicked();
+   void on_settingsRight_clicked();
+   void on_joyLeft_clicked();
+   void on_joyRight_clicked();
+   void on_settings_clicked();
 
-    void on_ctrlBtn_clicked();
+   void on_ctrlBtn_clicked();
 
 private:
-    Ui::MainWindow *ui;
+   Ui::MainWindow *ui;
 };
diff --git a/qtBuildSystem/Mu/touchscreen.cpp b/qtBuildSystem/Mu/touchscreen.cpp
index 97d3c5f..8479f8a 100644
--- a/qtBuildSystem/Mu/touchscreen.cpp
+++ b/qtBuildSystem/Mu/touchscreen.cpp
@@ -3,7 +3,7 @@
 #include "src/emulator.h"
 
 float rangeSwap(float newRange, float oldRange, float value){
-	return value / oldRange * newRange;
+   return value / oldRange * newRange;
 }
 
 TouchScreen::TouchScreen(QWidget* parent)
@@ -16,17 +16,17 @@ TouchScreen::~TouchScreen(){
 }
 
 void TouchScreen::mousePressEvent(QMouseEvent* ev){
-	palmInput.touchscreenX = (uint16_t)rangeSwap(screenWidth, this->width(), ev->x());
-	palmInput.touchscreenY = (uint16_t)rangeSwap(screenHeight, this->height(), ev->y());
+   palmInput.touchscreenX = (uint16_t)rangeSwap(screenWidth, this->width(), ev->x());
+   palmInput.touchscreenY = (uint16_t)rangeSwap(screenHeight, this->height(), ev->y());
 	palmInput.touchscreenTouched = true;
 }
 void TouchScreen::mouseMoveEvent(QMouseEvent* ev){
-	palmInput.touchscreenX = (uint16_t)rangeSwap(screenWidth, this->width(), ev->x());
-	palmInput.touchscreenY = (uint16_t)rangeSwap(screenHeight, this->height(), ev->y());
+   palmInput.touchscreenX = (uint16_t)rangeSwap(screenWidth, this->width(), ev->x());
+   palmInput.touchscreenY = (uint16_t)rangeSwap(screenHeight, this->height(), ev->y());
 }
 
 void TouchScreen::mouseReleaseEvent(QMouseEvent* ev){
-	palmInput.touchscreenTouched = false;
+   palmInput.touchscreenTouched = false;
 }
 
 /*
diff --git a/qtBuildSystem/Mu/touchscreen.h b/qtBuildSystem/Mu/touchscreen.h
index d9d69c0..61ed2ba 100644
--- a/qtBuildSystem/Mu/touchscreen.h
+++ b/qtBuildSystem/Mu/touchscreen.h
@@ -8,13 +8,13 @@ class TouchScreen : public QLabel
 {
 Q_OBJECT
 public:
-    explicit TouchScreen(QWidget* parent=0 );
-    ~TouchScreen();
+   explicit TouchScreen(QWidget* parent=0 );
+   ~TouchScreen();
 protected:
-    void mousePressEvent(QMouseEvent* ev);
-    void mouseMoveEvent(QMouseEvent* ev);
-    void mouseReleaseEvent(QMouseEvent* ev);
+   void mousePressEvent(QMouseEvent* ev);
+   void mouseMoveEvent(QMouseEvent* ev);
+   void mouseReleaseEvent(QMouseEvent* ev);
 
-	//void touchReleaseEvent(QTouchEvent* ev);
+   //void touchReleaseEvent(QTouchEvent* ev);
 };
 
diff --git a/src/emulator.c b/src/emulator.c
index a1bceb5..a7bb72c 100644
--- a/src/emulator.c
+++ b/src/emulator.c
@@ -38,6 +38,7 @@ double    palmCrystalCycles;//how many cycles before toggling the 32.768 kHz cry
 double    palmCycleCounter;//can be greater then 0 if too many cycles where run
 double    palmClockMultiplier;//used by the emulator to overclock the emulated Palm
 
+
 uint64_t (*emulatorGetSysTime)();
 uint64_t* (*emulatorGetSdCardStateChunkList)(uint64_t sessionId, uint64_t stateId);//returns the bps chunkIds for a stateId in the order they need to be applied
 void (*emulatorSetSdCardStateChunkList)(uint64_t sessionId, uint64_t stateId, uint64_t* data);//sets the bps chunkIds for a stateId in the order they need to be applied
@@ -52,12 +53,48 @@ static inline bool allSdCardCallbacksPresent(){
 }
 
 
+//debug
+#ifdef EMU_OPCODE_LEVEL_DEBUG
+#define LOGGED_OPCODES 10
+static bool invalidBehaviorAbort;
+static char disassemblyBuffer[LOGGED_OPCODES][100];//store the opcode and program counter for the last 10 opcodes
+
+static void invalidBehaviorCheck(){
+   for(uint32_t i = 0; i < LOGGED_OPCODES - 1; i++)
+      strcpy(disassemblyBuffer[i], disassemblyBuffer[i + 1]);
+
+   uint32_t programCounter = m68k_get_reg(NULL, M68K_REG_PC);
+   uint16_t instruction = m68k_get_reg(NULL, M68K_REG_IR);
+
+   m68k_disassemble(disassemblyBuffer[LOGGED_OPCODES - 1], programCounter, M68K_CPU_TYPE_68020);
+   strcat(disassemblyBuffer[LOGGED_OPCODES - 1], "\n");
+
+   if(bankType[programCounter >> 16] == EMPTY_BANK)
+      invalidBehaviorAbort = true;
+
+   if(!m68k_is_valid_instruction(instruction, M68K_CPU_TYPE_68020) || instruction == 0x0000){
+      //0x0000 is "ori.b #$0, D0", effectivly NOP but still a valid opcode
+      //usualy never encountered unless executing empty address space, so it still triggers debug abort
+      invalidBehaviorAbort = true;
+   }
+
+   if(invalidBehaviorAbort)
+      m68k_end_timeslice();
+}
+#endif
+
+
 void emulatorInit(uint8_t* palmRomDump, uint8_t* palmBootDump, uint32_t specialFeatures){
-   //cpu
+   //CPU
    m68k_init();
    m68k_set_cpu_type(M68K_CPU_TYPE_68020);
    m68k_set_reset_instr_callback(emulatorReset);
    m68k_set_int_ack_callback(interruptAcknowledge);
+#ifdef EMU_OPCODE_LEVEL_DEBUG
+   for(uint32_t i = 0; i < LOGGED_OPCODES; i++)
+      strcpy(disassemblyBuffer[i], "Not an opcode.\n");
+   m68k_set_instr_hook_callback(invalidBehaviorCheck);
+#endif
    patchMusashiOpcodeHandlerCpu32();
    resetHwRegisters();
    lowPowerStopActive = false;
@@ -342,3 +379,30 @@ void emulateFrame(){
 
    //debugLog("Ran frame, executed %f cycles.\n", palmCycleCounter + CPU_FREQUENCY / EMU_FPS);
 }
+
+bool emulateUntilDebugEventOrFrameEnd(){
+#ifdef EMU_OPCODE_LEVEL_DEBUG
+   invalidBehaviorAbort = false;
+
+   refreshButtonState();
+   while(palmCycleCounter < CPU_FREQUENCY / EMU_FPS){
+      if(cpuIsOn())
+         palmCycleCounter += m68k_execute(palmCrystalCycles * palmClockMultiplier) / palmClockMultiplier;//normaly 33mhz / 60fps
+      else
+         palmCycleCounter += palmCrystalCycles;
+      clk32();
+      if(invalidBehaviorAbort)
+         break;
+   }
+   palmCycleCounter -= CPU_FREQUENCY / EMU_FPS;
+
+   if(invalidBehaviorAbort)
+      for(uint32_t i = 0; i < LOGGED_OPCODES; i++)
+         debugLog(disassemblyBuffer[i]);
+
+   return invalidBehaviorAbort;
+#else
+   emulateFrame();
+   return false;
+#endif
+}
diff --git a/src/emulator.h b/src/emulator.h
index d12a310..07344eb 100644
--- a/src/emulator.h
+++ b/src/emulator.h
@@ -7,6 +7,8 @@
 
 #include <boolean.h>
 
+//to enable opcode level debugging define EMU_OPCODE_LEVEL_DEBUG
+
 #ifdef EMU_DEBUG
 #define debugLog(...) printf(__VA_ARGS__)
 #else
@@ -151,6 +153,7 @@ void emulatorSaveState(uint8_t* data);
 void emulatorLoadState(uint8_t* data);
 uint32_t emulatorInstallPrcPdb(uint8_t* data, uint32_t size);
 void emulateFrame();
+bool emulateUntilDebugEventOrFrameEnd();//false for frame end, true for debug event
    
 #ifdef __cplusplus
 }
diff --git a/src/hardwareRegisters.h b/src/hardwareRegisters.h
index e572adf..92ee59e 100644
--- a/src/hardwareRegisters.h
+++ b/src/hardwareRegisters.h
@@ -45,7 +45,7 @@ void setHwRegister32(unsigned int address, unsigned int value);
 //timing
 void clk32();//also checks all interrupts
 
-//cpu
+//CPU
 bool cpuIsOn();
 int  interruptAcknowledge(int intLevel);
 bool registersAreXXFFMapped();
diff --git a/src/m68k/m68kconf.h b/src/m68k/m68kconf.h
index 7e175ed..22e7ecb 100755
--- a/src/m68k/m68kconf.h
+++ b/src/m68k/m68kconf.h
@@ -130,7 +130,11 @@
 /* If ON, CPU will call the instruction hook callback before every
  * instruction.
  */
+#ifdef EMU_OPCODE_LEVEL_DEBUG
+#define M68K_INSTRUCTION_HOOK       OPT_ON
+#else
 #define M68K_INSTRUCTION_HOOK       OPT_OFF
+#endif
 #define M68K_INSTRUCTION_CALLBACK() your_instruction_hook_function()