9 files changed, 234 insertions, 211 deletions

diff --git a/src/citra_qt/bootmanager.cpp b/src/citra_qt/bootmanager.cpp
index a8bff9247..a7f949411 100644
--- a/src/citra_qt/bootmanager.cpp
+++ b/src/citra_qt/bootmanager.cpp
@@ -10,6 +10,7 @@
 
 #include "common/common.h"
 #include "bootmanager.h"
+#include "main.h"
 
 #include "core/core.h"
 #include "core/settings.h"
@@ -27,43 +28,33 @@
 #define COPYRIGHT       "Copyright (C) 2013-2014 Citra Team"
 
 EmuThread::EmuThread(GRenderWindow* render_window) :
-    filename(""), exec_cpu_step(false), cpu_running(false),
-    stop_run(false), render_window(render_window)
-{
-}
+    exec_step(false), running(false), stop_run(false), render_window(render_window) {
 
-void EmuThread::SetFilename(std::string filename)
-{
-    this->filename = filename;
+    connect(this, SIGNAL(started()), render_window, SLOT(moveContext()));
 }
 
-void EmuThread::run()
-{
+void EmuThread::run() {
     stop_run = false;
 
     // holds whether the cpu was running during the last iteration,
     // so that the DebugModeLeft signal can be emitted before the
     // next execution step
     bool was_active = false;
-    while (!stop_run)
-    {
-        if (cpu_running)
-        {
+    while (!stop_run) {
+        if (running) {
             if (!was_active)
                 emit DebugModeLeft();
 
             Core::RunLoop();
 
-            was_active = cpu_running || exec_cpu_step;
-            if (!was_active)
+            was_active = running || exec_step;
+            if (!was_active && !stop_run)
                 emit DebugModeEntered();
-        }
-        else if (exec_cpu_step)
-        {
+        } else if (exec_step) {
             if (!was_active)
                 emit DebugModeLeft();
 
-            exec_cpu_step = false;
+            exec_step = false;
             Core::SingleStep();
             emit DebugModeEntered();
             yieldCurrentThread();
@@ -71,47 +62,10 @@ void EmuThread::run()
             was_active = false;
         }
     }
-    render_window->moveContext();
-
-    Core::Stop();
-}
-
-void EmuThread::Stop()
-{
-    if (!isRunning())
-    {
-        LOG_WARNING(Frontend, "EmuThread::Stop called while emu thread wasn't running, returning...");
-        return;
-    }
-    stop_run = true;
 
-    // Release emu threads from any breakpoints, so that this doesn't hang forever.
-    Pica::g_debug_context->ClearBreakpoints();
-
-    //core::g_state = core::SYS_DIE;
-
-    // TODO: Waiting here is just a bad workaround for retarded shutdown logic.
-    wait(1000);
-    if (isRunning())
-    {
-        LOG_WARNING(Frontend, "EmuThread still running, terminating...");
-        quit();
-
-        // TODO: Waiting 50 seconds can be necessary if the logging subsystem has a lot of spam
-        // queued... This should be fixed.
-        wait(50000);
-        if (isRunning())
-        {
-            LOG_CRITICAL(Frontend, "EmuThread STILL running, something is wrong here...");
-            terminate();
-        }
-    }
-    LOG_INFO(Frontend, "EmuThread stopped");
-
-    System::Shutdown();
+    render_window->moveContext();
 }
 
-
 // This class overrides paintEvent and resizeEvent to prevent the GUI thread from stealing GL context.
 // The corresponding functionality is handled in EmuThread instead
 class GGLWidgetInternal : public QGLWidget
@@ -133,13 +87,9 @@ private:
     GRenderWindow* parent;
 };
 
-EmuThread& GRenderWindow::GetEmuThread()
-{
-    return emu_thread;
-}
+GRenderWindow::GRenderWindow(QWidget* parent, EmuThread* emu_thread) :
+    QWidget(parent), emu_thread(emu_thread), keyboard_id(0) {
 
-GRenderWindow::GRenderWindow(QWidget* parent) : QWidget(parent), emu_thread(this), keyboard_id(0)
-{
     std::string window_title = Common::StringFromFormat("Citra | %s-%s", Common::g_scm_branch, Common::g_scm_desc);
     setWindowTitle(QString::fromStdString(window_title));
 
@@ -160,7 +110,6 @@ GRenderWindow::GRenderWindow(QWidget* parent) : QWidget(parent), emu_thread(this
     layout->addWidget(child);
     layout->setMargin(0);
     setLayout(layout);
-    connect(&emu_thread, SIGNAL(started()), this, SLOT(moveContext()));
 
     OnMinimalClientAreaChangeRequest(GetActiveConfig().min_client_area_size);
 
@@ -180,29 +129,17 @@ void GRenderWindow::moveContext()
     // We need to move GL context to the swapping thread in Qt5
 #if QT_VERSION > QT_VERSION_CHECK(5, 0, 0)
     // If the thread started running, move the GL Context to the new thread. Otherwise, move it back.
-    child->context()->moveToThread((QThread::currentThread() == qApp->thread()) ? &emu_thread : qApp->thread());
+    auto thread = (QThread::currentThread() == qApp->thread() && emu_thread != nullptr) ? emu_thread : qApp->thread();
+    child->context()->moveToThread(thread);
 #endif
 }
 
-GRenderWindow::~GRenderWindow()
-{
-    if (emu_thread.isRunning())
-        emu_thread.Stop();
-}
-
 void GRenderWindow::SwapBuffers()
 {
     // MakeCurrent is already called in renderer_opengl
     child->swapBuffers();
 }
 
-void GRenderWindow::closeEvent(QCloseEvent* event)
-{
-    if (emu_thread.isRunning())
-        emu_thread.Stop();
-    QWidget::closeEvent(event);
-}
-
 void GRenderWindow::MakeCurrent()
 {
     child->makeCurrent();
@@ -335,3 +272,11 @@ void GRenderWindow::OnClientAreaResized(unsigned width, unsigned height)
 void GRenderWindow::OnMinimalClientAreaChangeRequest(const std::pair<unsigned,unsigned>& minimal_size) {
     setMinimumSize(minimal_size.first, minimal_size.second);
 }
+
+void GRenderWindow::OnEmulationStarting(EmuThread* emu_thread) {
+    this->emu_thread = emu_thread;
+}
+
+void GRenderWindow::OnEmulationStopping() {
+    emu_thread = nullptr;
+}
diff --git a/src/citra_qt/bootmanager.h b/src/citra_qt/bootmanager.h
index 288da45a1..715faf2d7 100644
--- a/src/citra_qt/bootmanager.h
+++ b/src/citra_qt/bootmanager.h
@@ -9,72 +9,58 @@
 
 #include "common/common.h"
 #include "common/emu_window.h"
+#include "common/thread.h"
 
 class QScreen;
 class QKeyEvent;
 
 class GRenderWindow;
+class GMainWindow;
 
 class EmuThread : public QThread
 {
     Q_OBJECT
 
 public:
-    /**
-     * Set image filename
-     *
-     * @param filename
-     * @warning Only call when not running!
-     */
-    void SetFilename(std::string filename);
+    EmuThread(GRenderWindow* render_window);
 
     /**
      * Start emulation (on new thread)
-     *
      * @warning Only call when not running!
      */
     void run() override;
 
     /**
-     * Allow the CPU to process a single instruction (if cpu is not running)
-     *
+     * Steps the emulation thread by a single CPU instruction (if the CPU is not already running)
      * @note This function is thread-safe
      */
-    void ExecStep() { exec_cpu_step = true; }
+    void ExecStep() { exec_step = true; }
 
     /**
-     * Allow the CPU to continue processing instructions without interruption
-     *
+     * Sets whether the emulation thread is running or not
+     * @param running Boolean value, set the emulation thread to running if true
      * @note This function is thread-safe
      */
-    void SetCpuRunning(bool running) { cpu_running = running; }
+    void SetRunning(bool running) { this->running = running; }
 
     /**
-    * Allow the CPU to continue processing instructions without interruption
-    *
-    * @note This function is thread-safe
-    */
-    bool IsCpuRunning() { return cpu_running; }
-
+     * Check if the emulation thread is running or not
+     * @return True if the emulation thread is running, otherwise false
+     * @note This function is thread-safe
+     */
+    bool IsRunning() { return running; }
 
-public slots:
     /**
-     * Stop emulation and wait for the thread to finish.
-     *
-     * @details: This function will wait a second for the thread to finish; if it hasn't finished until then, we'll terminate() it and wait another second, hoping that it will be terminated by then.
-     * @note: This function is thread-safe.
+     * Requests for the emulation thread to stop running
      */
-    void Stop();
+    void RequestStop() {
+        stop_run = true;
+        running = false;
+    };
 
 private:
-    friend class GRenderWindow;
-
-    EmuThread(GRenderWindow* render_window);
-
-    std::string filename;
-
-    bool exec_cpu_step;
-    bool cpu_running;
+    bool exec_step;
+    bool running;
     std::atomic<bool> stop_run;
 
     GRenderWindow* render_window;
@@ -100,10 +86,7 @@ class GRenderWindow : public QWidget, public EmuWindow
     Q_OBJECT
 
 public:
-    GRenderWindow(QWidget* parent = NULL);
-    ~GRenderWindow();
-
-    void closeEvent(QCloseEvent*) override;
+    GRenderWindow(QWidget* parent, EmuThread* emu_thread);
 
     // EmuWindow implementation
     void SwapBuffers() override;
@@ -116,8 +99,6 @@ public:
     void restoreGeometry(const QByteArray& geometry); // overridden
     QByteArray saveGeometry();  // overridden
 
-    EmuThread& GetEmuThread();
-
     void keyPressEvent(QKeyEvent* event) override;
     void keyReleaseEvent(QKeyEvent* event) override;
 
@@ -134,15 +115,18 @@ public:
 public slots:
     void moveContext();  // overridden
 
+    void OnEmulationStarting(EmuThread* emu_thread);
+    void OnEmulationStopping();
+
 private:
     void OnMinimalClientAreaChangeRequest(const std::pair<unsigned,unsigned>& minimal_size) override;
 
     QGLWidget* child;
 
-    EmuThread emu_thread;
-
     QByteArray geometry;
 
     /// Device id of keyboard for use with KeyMap
     int keyboard_id;
+
+    EmuThread* emu_thread;
 };
diff --git a/src/citra_qt/debugger/disassembler.cpp b/src/citra_qt/debugger/disassembler.cpp
index f620687ae..08c6b49bd 100644
--- a/src/citra_qt/debugger/disassembler.cpp
+++ b/src/citra_qt/debugger/disassembler.cpp
@@ -18,8 +18,8 @@
 #include "core/arm/disassembler/arm_disasm.h"
 
 
-DisassemblerModel::DisassemblerModel(QObject* parent) : QAbstractListModel(parent), base_address(0), code_size(0), program_counter(0), selection(QModelIndex()) {
-
+DisassemblerModel::DisassemblerModel(QObject* parent) :
+    QAbstractListModel(parent), base_address(0), code_size(0), program_counter(0), selection(QModelIndex()) {
 }
 
 int DisassemblerModel::columnCount(const QModelIndex& parent) const {
@@ -158,34 +158,28 @@ void DisassemblerModel::SetNextInstruction(unsigned int address) {
     emit dataChanged(prev_index, prev_index);
 }
 
-DisassemblerWidget::DisassemblerWidget(QWidget* parent, EmuThread& emu_thread) : QDockWidget(parent), base_addr(0), emu_thread(emu_thread)
-{
-    disasm_ui.setupUi(this);
+DisassemblerWidget::DisassemblerWidget(QWidget* parent, EmuThread* emu_thread) :
+    QDockWidget(parent), emu_thread(emu_thread), base_addr(0) {
 
-    model = new DisassemblerModel(this);
-    disasm_ui.treeView->setModel(model);
+    disasm_ui.setupUi(this);
 
     RegisterHotkey("Disassembler", "Start/Stop", QKeySequence(Qt::Key_F5), Qt::ApplicationShortcut);
     RegisterHotkey("Disassembler", "Step", QKeySequence(Qt::Key_F10), Qt::ApplicationShortcut);
     RegisterHotkey("Disassembler", "Step into", QKeySequence(Qt::Key_F11), Qt::ApplicationShortcut);
     RegisterHotkey("Disassembler", "Set Breakpoint", QKeySequence(Qt::Key_F9), Qt::ApplicationShortcut);
 
-    connect(disasm_ui.button_breakpoint, SIGNAL(clicked()), model, SLOT(OnSetOrUnsetBreakpoint()));
     connect(disasm_ui.button_step, SIGNAL(clicked()), this, SLOT(OnStep()));
     connect(disasm_ui.button_pause, SIGNAL(clicked()), this, SLOT(OnPause()));
     connect(disasm_ui.button_continue, SIGNAL(clicked()), this, SLOT(OnContinue()));
 
-    connect(disasm_ui.treeView->selectionModel(), SIGNAL(currentChanged(const QModelIndex&, const QModelIndex&)),
-            model, SLOT(OnSelectionChanged(const QModelIndex&)));
-
     connect(GetHotkey("Disassembler", "Start/Stop", this), SIGNAL(activated()), this, SLOT(OnToggleStartStop()));
     connect(GetHotkey("Disassembler", "Step", this), SIGNAL(activated()), this, SLOT(OnStep()));
     connect(GetHotkey("Disassembler", "Step into", this), SIGNAL(activated()), this, SLOT(OnStepInto()));
-    connect(GetHotkey("Disassembler", "Set Breakpoint", this), SIGNAL(activated()), model, SLOT(OnSetOrUnsetBreakpoint()));
+
+    setEnabled(false);
 }
 
-void DisassemblerWidget::Init()
-{
+void DisassemblerWidget::Init() {
     model->ParseFromAddress(Core::g_app_core->GetPC());
 
     disasm_ui.treeView->resizeColumnToContents(0);
@@ -197,25 +191,21 @@ void DisassemblerWidget::Init()
     disasm_ui.treeView->selectionModel()->setCurrentIndex(model_index, QItemSelectionModel::SelectCurrent | QItemSelectionModel::Rows);
 }
 
-void DisassemblerWidget::OnContinue()
-{
-    emu_thread.SetCpuRunning(true);
+void DisassemblerWidget::OnContinue() {
+    emu_thread->SetRunning(true);
 }
 
-void DisassemblerWidget::OnStep()
-{
+void DisassemblerWidget::OnStep() {
     OnStepInto(); // change later
 }
 
-void DisassemblerWidget::OnStepInto()
-{
-    emu_thread.SetCpuRunning(false);
-    emu_thread.ExecStep();
+void DisassemblerWidget::OnStepInto() {
+    emu_thread->SetRunning(false);
+    emu_thread->ExecStep();
 }
 
-void DisassemblerWidget::OnPause()
-{
-    emu_thread.SetCpuRunning(false);
+void DisassemblerWidget::OnPause() {
+    emu_thread->SetRunning(false);
 
     // TODO: By now, the CPU might not have actually stopped...
     if (Core::g_app_core) {
@@ -223,17 +213,15 @@ void DisassemblerWidget::OnPause()
     }
 }
 
-void DisassemblerWidget::OnToggleStartStop()
-{
-    emu_thread.SetCpuRunning(!emu_thread.IsCpuRunning());
+void DisassemblerWidget::OnToggleStartStop() {
+    emu_thread->SetRunning(!emu_thread->IsRunning());
 }
 
-void DisassemblerWidget::OnDebugModeEntered()
-{
+void DisassemblerWidget::OnDebugModeEntered() {
     ARMword next_instr = Core::g_app_core->GetPC();
 
     if (model->GetBreakPoints().IsAddressBreakPoint(next_instr))
-        emu_thread.SetCpuRunning(false);
+        emu_thread->SetRunning(false);
 
     model->SetNextInstruction(next_instr);
 
@@ -242,16 +230,35 @@ void DisassemblerWidget::OnDebugModeEntered()
     disasm_ui.treeView->selectionModel()->setCurrentIndex(model_index, QItemSelectionModel::SelectCurrent | QItemSelectionModel::Rows);
 }
 
-void DisassemblerWidget::OnDebugModeLeft()
-{
-
+void DisassemblerWidget::OnDebugModeLeft() {
 }
 
-int DisassemblerWidget::SelectedRow()
-{
+int DisassemblerWidget::SelectedRow() {
     QModelIndex index = disasm_ui.treeView->selectionModel()->currentIndex();
     if (!index.isValid())
         return -1;
 
     return disasm_ui.treeView->selectionModel()->currentIndex().row();
 }
+
+void DisassemblerWidget::OnEmulationStarting(EmuThread* emu_thread) {
+    this->emu_thread = emu_thread;
+
+    model = new DisassemblerModel(this);
+    disasm_ui.treeView->setModel(model);
+
+    connect(disasm_ui.treeView->selectionModel(), SIGNAL(currentChanged(const QModelIndex&, const QModelIndex&)),
+        model, SLOT(OnSelectionChanged(const QModelIndex&)));
+    connect(disasm_ui.button_breakpoint, SIGNAL(clicked()), model, SLOT(OnSetOrUnsetBreakpoint()));
+    connect(GetHotkey("Disassembler", "Set Breakpoint", this), SIGNAL(activated()), model, SLOT(OnSetOrUnsetBreakpoint()));
+
+    Init();
+    setEnabled(true);
+}
+
+void DisassemblerWidget::OnEmulationStopping() {
+    disasm_ui.treeView->setModel(nullptr);
+    delete model;
+    emu_thread = nullptr;
+    setEnabled(false);
+}
diff --git a/src/citra_qt/debugger/disassembler.h b/src/citra_qt/debugger/disassembler.h
index 5e19d7c51..45b0a7e08 100644
--- a/src/citra_qt/debugger/disassembler.h
+++ b/src/citra_qt/debugger/disassembler.h
@@ -51,7 +51,7 @@ class DisassemblerWidget : public QDockWidget
     Q_OBJECT
 
 public:
-    DisassemblerWidget(QWidget* parent, EmuThread& emu_thread);
+    DisassemblerWidget(QWidget* parent, EmuThread* emu_thread);
 
     void Init();
 
@@ -65,6 +65,9 @@ public slots:
     void OnDebugModeEntered();
     void OnDebugModeLeft();
 
+    void OnEmulationStarting(EmuThread* emu_thread);
+    void OnEmulationStopping();
+
 private:
     // returns -1 if no row is selected
     int SelectedRow();
@@ -75,5 +78,5 @@ private:
 
     u32 base_addr;
 
-    EmuThread& emu_thread;
+    EmuThread* emu_thread;
 };
diff --git a/src/citra_qt/debugger/registers.cpp b/src/citra_qt/debugger/registers.cpp
index ab3666156..5527a2afd 100644
--- a/src/citra_qt/debugger/registers.cpp
+++ b/src/citra_qt/debugger/registers.cpp
@@ -7,8 +7,7 @@
 #include "core/core.h"
 #include "core/arm/arm_interface.h"
 
-RegistersWidget::RegistersWidget(QWidget* parent) : QDockWidget(parent)
-{
+RegistersWidget::RegistersWidget(QWidget* parent) : QDockWidget(parent) {
     cpu_regs_ui.setupUi(this);
 
     tree = cpu_regs_ui.treeWidget;
@@ -18,8 +17,7 @@ RegistersWidget::RegistersWidget(QWidget* parent) : QDockWidget(parent)
     registers->setExpanded(true);
     CSPR->setExpanded(true);
 
-    for (int i = 0; i < 16; ++i)
-    {
+    for (int i = 0; i < 16; ++i) {
         QTreeWidgetItem* child = new QTreeWidgetItem(QStringList(QString("R[%1]").arg(i, 2, 10, QLatin1Char('0'))));
         registers->addChild(child);
     }
@@ -39,12 +37,16 @@ RegistersWidget::RegistersWidget(QWidget* parent) : QDockWidget(parent)
     CSPR->addChild(new QTreeWidgetItem(QStringList("C")));
     CSPR->addChild(new QTreeWidgetItem(QStringList("Z")));
     CSPR->addChild(new QTreeWidgetItem(QStringList("N")));
+
+    setEnabled(false);
 }
 
-void RegistersWidget::OnDebugModeEntered()
-{
+void RegistersWidget::OnDebugModeEntered() {
     ARM_Interface* app_core = Core::g_app_core;
 
+    if (app_core == nullptr)
+        return;
+
     for (int i = 0; i < 16; ++i)
         registers->child(i)->setText(1, QString("0x%1").arg(app_core->GetReg(i), 8, 16, QLatin1Char('0')));
 
@@ -66,7 +68,22 @@ void RegistersWidget::OnDebugModeEntered()
     CSPR->child(14)->setText(1, QString("%1").arg((app_core->GetCPSR() >> 31) & 0x1));  // N - Negative/Less than
 }
 
-void RegistersWidget::OnDebugModeLeft()
-{
+void RegistersWidget::OnDebugModeLeft() {
+}
+
+void RegistersWidget::OnEmulationStarting(EmuThread* emu_thread) {
+    setEnabled(true);
+}
+
+void RegistersWidget::OnEmulationStopping() {
+    // Reset widget text
+    for (int i = 0; i < 16; ++i)
+        registers->child(i)->setText(1, QString(""));
+
+    for (int i = 0; i < 15; ++i)
+        CSPR->child(i)->setText(1, QString(""));
+
+    CSPR->setText(1, QString(""));
 
+    setEnabled(false);
 }
diff --git a/src/citra_qt/debugger/registers.h b/src/citra_qt/debugger/registers.h
index bf8955625..68e3fb908 100644
--- a/src/citra_qt/debugger/registers.h
+++ b/src/citra_qt/debugger/registers.h
@@ -8,6 +8,7 @@
 #include <QTreeWidgetItem>
 
 class QTreeWidget;
+class EmuThread;
 
 class RegistersWidget : public QDockWidget
 {
@@ -20,6 +21,9 @@ public slots:
     void OnDebugModeEntered();
     void OnDebugModeLeft();
 
+    void OnEmulationStarting(EmuThread* emu_thread);
+    void OnEmulationStopping();
+
 private:
     Ui::ARMRegisters cpu_regs_ui;
 
diff --git a/src/citra_qt/main.cpp b/src/citra_qt/main.cpp
index e5ca04124..dd0e4de8f 100644
--- a/src/citra_qt/main.cpp
+++ b/src/citra_qt/main.cpp
@@ -15,6 +15,7 @@
 #include "common/logging/log.h"
 #include "common/logging/backend.h"
 #include "common/logging/filter.h"
+#include "common/make_unique.h"
 #include "common/platform.h"
 #include "common/scope_exit.h"
 
@@ -46,7 +47,7 @@
 
 #include "version.h"
 
-GMainWindow::GMainWindow()
+GMainWindow::GMainWindow() : emu_thread(nullptr)
 {
     Pica::g_debug_context = Pica::DebugContext::Construct();
 
@@ -55,14 +56,14 @@ GMainWindow::GMainWindow()
     ui.setupUi(this);
     statusBar()->hide();
 
-    render_window = new GRenderWindow;
+    render_window = new GRenderWindow(this, emu_thread.get());
     render_window->hide();
 
     profilerWidget = new ProfilerWidget(this);
     addDockWidget(Qt::BottomDockWidgetArea, profilerWidget);
     profilerWidget->hide();
 
-    disasmWidget = new DisassemblerWidget(this, render_window->GetEmuThread());
+    disasmWidget = new DisassemblerWidget(this, emu_thread.get());
     addDockWidget(Qt::BottomDockWidgetArea, disasmWidget);
     disasmWidget->hide();
 
@@ -138,14 +139,12 @@ GMainWindow::GMainWindow()
     connect(ui.action_Single_Window_Mode, SIGNAL(triggered(bool)), this, SLOT(ToggleWindowMode()));
     connect(ui.action_Hotkeys, SIGNAL(triggered()), this, SLOT(OnOpenHotkeysDialog()));
 
-    // BlockingQueuedConnection is important here, it makes sure we've finished refreshing our views before the CPU continues
-    connect(&render_window->GetEmuThread(), SIGNAL(DebugModeEntered()), disasmWidget, SLOT(OnDebugModeEntered()), Qt::BlockingQueuedConnection);
-    connect(&render_window->GetEmuThread(), SIGNAL(DebugModeEntered()), registersWidget, SLOT(OnDebugModeEntered()), Qt::BlockingQueuedConnection);
-    connect(&render_window->GetEmuThread(), SIGNAL(DebugModeEntered()), callstackWidget, SLOT(OnDebugModeEntered()), Qt::BlockingQueuedConnection);
-    
-    connect(&render_window->GetEmuThread(), SIGNAL(DebugModeLeft()), disasmWidget, SLOT(OnDebugModeLeft()), Qt::BlockingQueuedConnection);
-    connect(&render_window->GetEmuThread(), SIGNAL(DebugModeLeft()), registersWidget, SLOT(OnDebugModeLeft()), Qt::BlockingQueuedConnection);
-    connect(&render_window->GetEmuThread(), SIGNAL(DebugModeLeft()), callstackWidget, SLOT(OnDebugModeLeft()), Qt::BlockingQueuedConnection);
+    connect(this, SIGNAL(EmulationStarting(EmuThread*)), disasmWidget, SLOT(OnEmulationStarting(EmuThread*)));
+    connect(this, SIGNAL(EmulationStopping()), disasmWidget, SLOT(OnEmulationStopping()));
+    connect(this, SIGNAL(EmulationStarting(EmuThread*)), registersWidget, SLOT(OnEmulationStarting(EmuThread*)));
+    connect(this, SIGNAL(EmulationStopping()), registersWidget, SLOT(OnEmulationStopping()));
+    connect(this, SIGNAL(EmulationStarting(EmuThread*)), render_window, SLOT(OnEmulationStarting(EmuThread*)));
+    connect(this, SIGNAL(EmulationStopping()), render_window, SLOT(OnEmulationStopping()));
 
     // Setup hotkeys
     RegisterHotkey("Main Window", "Load File", QKeySequence::Open);
@@ -196,32 +195,76 @@ void GMainWindow::OnDisplayTitleBars(bool show)
     }
 }
 
-void GMainWindow::BootGame(std::string filename)
-{
+void GMainWindow::BootGame(std::string filename) {
     LOG_INFO(Frontend, "Citra starting...\n");
+
+    // Initialize the core emulation
     System::Init(render_window);
 
-    // Load a game or die...
+    // Load the game
     if (Loader::ResultStatus::Success != Loader::LoadFile(filename)) {
         LOG_CRITICAL(Frontend, "Failed to load ROM!");
+        System::Shutdown();
+        return;
     }
 
-    disasmWidget->Init();
+    // Create and start the emulation thread
+    emu_thread = Common::make_unique<EmuThread>(render_window);
+    emit EmulationStarting(emu_thread.get());
+    emu_thread->start();
+
+    // BlockingQueuedConnection is important here, it makes sure we've finished refreshing our views before the CPU continues
+    connect(emu_thread.get(), SIGNAL(DebugModeEntered()), disasmWidget, SLOT(OnDebugModeEntered()), Qt::BlockingQueuedConnection);
+    connect(emu_thread.get(), SIGNAL(DebugModeEntered()), registersWidget, SLOT(OnDebugModeEntered()), Qt::BlockingQueuedConnection);
+    connect(emu_thread.get(), SIGNAL(DebugModeEntered()), callstackWidget, SLOT(OnDebugModeEntered()), Qt::BlockingQueuedConnection);
+    connect(emu_thread.get(), SIGNAL(DebugModeLeft()), disasmWidget, SLOT(OnDebugModeLeft()), Qt::BlockingQueuedConnection);
+    connect(emu_thread.get(), SIGNAL(DebugModeLeft()), registersWidget, SLOT(OnDebugModeLeft()), Qt::BlockingQueuedConnection);
+    connect(emu_thread.get(), SIGNAL(DebugModeLeft()), callstackWidget, SLOT(OnDebugModeLeft()), Qt::BlockingQueuedConnection);
+
+    // Update the GUI
     registersWidget->OnDebugModeEntered();
     callstackWidget->OnDebugModeEntered();
-
-    render_window->GetEmuThread().SetFilename(filename);
-    render_window->GetEmuThread().start();
-
     render_window->show();
+
     OnStartGame();
 }
 
+void GMainWindow::ShutdownGame() {
+    emu_thread->RequestStop();
+
+    // Release emu threads from any breakpoints
+    // This belongs after RequestStop() and before wait() because if emulation stops on a GPU
+    // breakpoint after (or before) RequestStop() is called, the emulation would never be able
+    // to continue out to the main loop and terminate. Thus wait() would hang forever.
+    // TODO(bunnei): This function is not thread safe, but it's being used as if it were
+    Pica::g_debug_context->ClearBreakpoints();
+
+    emit EmulationStopping();
+
+    // Wait for emulation thread to complete and delete it
+    emu_thread->wait();
+    emu_thread = nullptr;
+
+    // Shutdown the core emulation
+    System::Shutdown();
+
+    // Update the GUI
+    ui.action_Start->setEnabled(false);
+    ui.action_Pause->setEnabled(false);
+    ui.action_Stop->setEnabled(false);
+    render_window->hide();
+}
+
 void GMainWindow::OnMenuLoadFile()
 {
     QString filename = QFileDialog::getOpenFileName(this, tr("Load File"), QString(), tr("3DS executable (*.3ds *.3dsx *.elf *.axf *.bin *.cci *.cxi)"));
-    if (filename.size())
-       BootGame(filename.toLatin1().data());
+    if (filename.size()) {
+        // Shutdown previous session if the emu thread is still active...
+        if (emu_thread != nullptr)
+            ShutdownGame();
+
+        BootGame(filename.toLatin1().data());
+    }
 }
 
 void GMainWindow::OnMenuLoadSymbolMap() {
@@ -232,7 +275,7 @@ void GMainWindow::OnMenuLoadSymbolMap() {
 
 void GMainWindow::OnStartGame()
 {
-    render_window->GetEmuThread().SetCpuRunning(true);
+    emu_thread->SetRunning(true);
 
     ui.action_Start->setEnabled(false);
     ui.action_Pause->setEnabled(true);
@@ -241,21 +284,15 @@ void GMainWindow::OnStartGame()
 
 void GMainWindow::OnPauseGame()
 {
-    render_window->GetEmuThread().SetCpuRunning(false);
+    emu_thread->SetRunning(false);
 
     ui.action_Start->setEnabled(true);
     ui.action_Pause->setEnabled(false);
     ui.action_Stop->setEnabled(true);
 }
 
-void GMainWindow::OnStopGame()
-{
-    render_window->GetEmuThread().SetCpuRunning(false);
-    // TODO: Shutdown core
-
-    ui.action_Start->setEnabled(true);
-    ui.action_Pause->setEnabled(false);
-    ui.action_Stop->setEnabled(false);
+void GMainWindow::OnStopGame() {
+    ShutdownGame();
 }
 
 void GMainWindow::OnOpenHotkeysDialog()
@@ -265,24 +302,22 @@ void GMainWindow::OnOpenHotkeysDialog()
 }
 
 
-void GMainWindow::ToggleWindowMode()
-{
-    bool enable = ui.action_Single_Window_Mode->isChecked();
-    if (!enable && render_window->parent() != nullptr)
-    {
-        ui.horizontalLayout->removeWidget(render_window);
-        render_window->setParent(nullptr);
-        render_window->setVisible(true);
-        render_window->RestoreGeometry();
-        render_window->setFocusPolicy(Qt::NoFocus);
-    }
-    else if (enable && render_window->parent() == nullptr)
-    {
+void GMainWindow::ToggleWindowMode() {
+    if (ui.action_Single_Window_Mode->isChecked()) {
+        // Render in the main window...
         render_window->BackupGeometry();
         ui.horizontalLayout->addWidget(render_window);
         render_window->setVisible(true);
         render_window->setFocusPolicy(Qt::ClickFocus);
         render_window->setFocus();
+
+    } else {
+        // Render in a separate window...
+        ui.horizontalLayout->removeWidget(render_window);
+        render_window->setParent(nullptr);
+        render_window->setVisible(true);
+        render_window->RestoreGeometry();
+        render_window->setFocusPolicy(Qt::NoFocus);
     }
 }
 
@@ -303,6 +338,8 @@ void GMainWindow::closeEvent(QCloseEvent* event)
     settings.setValue("firstStart", false);
     SaveHotkeys(settings);
 
+    ShutdownGame();
+
     render_window->close();
 
     QWidget::closeEvent(event);
diff --git a/src/citra_qt/main.h b/src/citra_qt/main.h
index 9b57c5772..3e29534fb 100644
--- a/src/citra_qt/main.h
+++ b/src/citra_qt/main.h
@@ -5,12 +5,14 @@
 #ifndef _CITRA_QT_MAIN_HXX_
 #define _CITRA_QT_MAIN_HXX_
 
+#include <memory>
 #include <QMainWindow>
 
 #include "ui_main.h"
 
 class GImageInfo;
 class GRenderWindow;
+class EmuThread;
 class ProfilerWidget;
 class DisassemblerWidget;
 class RegistersWidget;
@@ -34,8 +36,27 @@ public:
     GMainWindow();
     ~GMainWindow();
 
+signals:
+
+    /**
+     * Signal that is emitted when a new EmuThread has been created and an emulation session is
+     * about to start. At this time, the core system emulation has been initialized, and all
+     * emulation handles and memory should be valid.
+     *
+     * @param emu_thread Pointer to the newly created EmuThread (to be used by widgets that need to
+     *      access/change emulation state).
+     */
+    void EmulationStarting(EmuThread* emu_thread);
+
+    /**
+     * Signal that is emitted when emulation is about to stop. At this time, the EmuThread and core
+     * system emulation handles and memory are still valid, but are about become invalid.
+     */
+    void EmulationStopping();
+
 private:
     void BootGame(std::string filename);
+    void ShutdownGame();
 
     void closeEvent(QCloseEvent* event) override;
 
@@ -55,6 +76,8 @@ private:
 
     GRenderWindow* render_window;
 
+    std::unique_ptr<EmuThread> emu_thread;
+
     ProfilerWidget* profilerWidget;
     DisassemblerWidget* disasmWidget;
     RegistersWidget* registersWidget;
diff --git a/src/citra_qt/main.ui b/src/citra_qt/main.ui
index a3752ac1e..689806465 100644
--- a/src/citra_qt/main.ui
+++ b/src/citra_qt/main.ui
@@ -90,6 +90,9 @@
    </property>
   </action>
   <action name="action_Start">
+   <property name="enabled">
+     <bool>false</bool>
+   </property>
    <property name="text">
     <string>&amp;Start</string>
    </property>