Qt: Initial CPU debugger widget implementation

Co-Authored-By: liuk707 <62625900+liuk7071@users.noreply.github.com>

CMakeLists.txt

@@ -733,12 +733,12 @@ if(NOT BUILD_HYDRA_CORE AND NOT BUILD_LIBRETRO_CORE)
         set(FRONTEND_SOURCE_FILES src/panda_qt/main.cpp src/panda_qt/screen.cpp src/panda_qt/main_window.cpp src/panda_qt/about_window.cpp
             src/panda_qt/config_window.cpp src/panda_qt/zep.cpp src/panda_qt/text_editor.cpp src/panda_qt/cheats_window.cpp src/panda_qt/mappings.cpp
             src/panda_qt/patch_window.cpp src/panda_qt/elided_label.cpp src/panda_qt/shader_editor.cpp src/panda_qt/translations.cpp
-            src/panda_qt/thread_debugger.cpp
+            src/panda_qt/thread_debugger.cpp src/panda_qt/cpu_debugger.cpp
         )
         set(FRONTEND_HEADER_FILES include/panda_qt/screen.hpp include/panda_qt/main_window.hpp include/panda_qt/about_window.hpp
             include/panda_qt/config_window.hpp include/panda_qt/text_editor.hpp include/panda_qt/cheats_window.hpp
             include/panda_qt/patch_window.hpp include/panda_qt/elided_label.hpp include/panda_qt/shader_editor.hpp
-            include/panda_qt/thread_debugger.hpp
+            include/panda_qt/thread_debugger.hpp include/panda_qt/cpu_debugger.hpp include/panda_qt/disabled_widget_overlay.hpp
         )
 
         source_group("Source Files\\Qt" FILES ${FRONTEND_SOURCE_FILES})

include/capstone.hpp

@@ -23,7 +23,7 @@ namespace Common {
 		// pc: program counter of the instruction to disassemble
 		// bytes: Byte representation of instruction
 		// buffer: text buffer to output the disassembly too
-		usize disassemble(std::string& buffer, u32 pc, std::span<u8> bytes, u64 offset = 0) {
+		usize disassemble(std::string& buffer, u32 pc, std::span<const u8> bytes, u64 offset = 0) {
 			if (!initialized) {
 				buffer = "Capstone was not properly initialized";
 				return 0;

include/emulator.hpp

@@ -122,14 +122,16 @@ class Emulator {
 	// Reloads some settings that require special handling, such as audio enable
 	void reloadSettings();
 
+	CPU& getCPU() { return cpu; }
+	Memory& getMemory() { return memory; }
+	Kernel& getKernel() { return kernel; }
+	Scheduler& getScheduler() { return scheduler; }
+
 	EmulatorConfig& getConfig() { return config; }
 	Cheats& getCheats() { return cheats; }
 	ServiceManager& getServiceManager() { return kernel.getServiceManager(); }
 	LuaManager& getLua() { return lua; }
-	Scheduler& getScheduler() { return scheduler; }
-	Memory& getMemory() { return memory; }
 	AudioDeviceInterface& getAudioDevice() { return audioDevice; }
-	Kernel& getKernel() { return kernel; }
 
 	RendererType getRendererType() const { return config.rendererType; }
 	Renderer* getRenderer() { return gpu.getRenderer(); }

include/panda_qt/cpu_debugger.hpp

@@ -0,0 +1,38 @@
+#pragma once
+#include <QListWidget>
+#include <QPlainTextEdit>
+#include <QScrollBar>
+#include <QWidget>
+
+#include "emulator.hpp"
+#include "panda_qt/disabled_widget_overlay.hpp"
+
+class CPUDebugger : public QWidget {
+	Q_OBJECT
+	Emulator* emu;
+
+	QListWidget* disasmListWidget;
+	QScrollBar* verticalScrollBar;
+	QPlainTextEdit* registerTextEdit;
+
+	DisabledWidgetOverlay* disabledOverlay;
+
+	bool enabled = false;
+
+  public:
+	CPUDebugger(Emulator* emulator, QWidget* parent = nullptr);
+	void enable();
+	void disable();
+
+  private:
+	// Update the state of the disassembler. Qt events should always call update, not updateDisasm/updateRegister
+	// As update properly handles thread safety
+	void update();
+	void updateDisasm();
+	void updateRegisters();
+
+	bool eventFilter(QObject* obj, QEvent* event) override;
+	void showEvent(QShowEvent* event) override;
+	void resizeEvent(QResizeEvent* event) override;
+	void keyPressEvent(QKeyEvent* event);
+};

include/panda_qt/disabled_widget_overlay.hpp

@@ -0,0 +1,28 @@
+#pragma once
+
+#include <QtWidgets>
+
+class DisabledWidgetOverlay : public QWidget {
+	Q_OBJECT
+
+  public:
+	DisabledWidgetOverlay(QWidget *parent = nullptr, QString overlayText = tr("This widget is disabled")) : text(overlayText), QWidget(parent) {
+		setVisible(false);
+	}
+
+  private:
+	QString text;
+
+	void paintEvent(QPaintEvent *) override {
+		QPainter painter = QPainter(this);
+		painter.fillRect(rect(), QColor(60, 60, 60, 128));
+		painter.setPen(Qt::gray);
+
+		QFont font = painter.font();
+		font.setBold(true);
+		font.setPointSize(18);
+
+		painter.setFont(font);
+		painter.drawText(rect(), Qt::AlignCenter, text);
+	}
+};

include/panda_qt/main_window.hpp

@@ -17,6 +17,7 @@
 #include "panda_qt/about_window.hpp"
 #include "panda_qt/cheats_window.hpp"
 #include "panda_qt/config_window.hpp"
+#include "panda_qt/cpu_debugger.hpp"
 #include "panda_qt/patch_window.hpp"
 #include "panda_qt/screen.hpp"
 #include "panda_qt/shader_editor.hpp"
@@ -110,6 +111,7 @@ class MainWindow : public QMainWindow {
 	TextEditorWindow* luaEditor;
 	PatchWindow* patchWindow;
 	ShaderEditorWindow* shaderEditor;
+	CPUDebugger* cpuDebugger;
 	ThreadDebugger* threadDebugger;
 
 	// We use SDL's game controller API since it's the sanest API that supports as many controllers as possible

src/panda_qt/cpu_debugger.cpp

@@ -0,0 +1,232 @@
+#include "panda_qt/cpu_debugger.hpp"
+
+#include <fmt/format.h>
+
+#include <QGridLayout>
+#include <QHBoxLayout>
+#include <QListWidget>
+#include <QPlainTextEdit>
+#include <QPushButton>
+#include <span>
+#include <utility>
+
+#include "capstone.hpp"
+
+static int getLinesInViewport(QListWidget* listWidget) {
+	auto viewportHeight = listWidget->viewport()->height();
+	QFontMetrics fm = QFontMetrics(listWidget->font());
+	auto lineHeight = fm.height();
+
+	return int(viewportHeight / lineHeight);
+}
+
+static std::pair<int, int> getVisibleLineRange(QListWidget* listWidget, QScrollBar* scrollBar) {
+	int firstLine = scrollBar->value();
+	int lineCount = getLinesInViewport(listWidget);
+
+	return {firstLine, lineCount};
+}
+
+CPUDebugger::CPUDebugger(Emulator* emulator, QWidget* parent) : emu(emulator), QWidget(parent, Qt::Window) {
+	setWindowTitle(tr("CPU debugger"));
+	resize(1000, 600);
+
+	// Main grid layout
+	QGridLayout* gridLayout = new QGridLayout(this);
+
+	// Top row: buttons in a horizontal layout
+	QHBoxLayout* horizontalLayout = new QHBoxLayout();
+	QPushButton* stepButton = new QPushButton(tr("Step"), this);
+	QPushButton* goToAddressButton = new QPushButton(tr("Go to address"), this);
+	QPushButton* goToPCButton = new QPushButton(tr("Go to PC"), this);
+
+	horizontalLayout->addWidget(stepButton);
+	horizontalLayout->addWidget(goToAddressButton);
+	horizontalLayout->addWidget(goToPCButton);
+	gridLayout->addLayout(horizontalLayout, 0, 0);
+
+	// Disassembly list on the left
+	disasmListWidget = new QListWidget(this);
+	gridLayout->addWidget(disasmListWidget, 1, 0);
+
+	// Vertical scroll bar in the middle
+	verticalScrollBar = new QScrollBar(Qt::Vertical, this);
+	gridLayout->addWidget(verticalScrollBar, 1, 1);
+
+	// Register view on the right
+	registerTextEdit = new QPlainTextEdit(this);
+	registerTextEdit->setEnabled(true);
+	registerTextEdit->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
+	registerTextEdit->setMaximumWidth(800);
+	gridLayout->addWidget(registerTextEdit, 1, 2);
+
+	// Setup disabled widget overlay
+	disabledOverlay = new DisabledWidgetOverlay(this, tr("Pause the emulator to use the CPU Debugger"));
+	disabledOverlay->resize(size());  // Fill the whole screen
+	disabledOverlay->raise();
+	disabledOverlay->hide();
+
+	// Monospace font
+	QFont mono_font = QFont("Courier New");
+	mono_font.setStyleHint(QFont::Monospace);
+	disasmListWidget->setFont(mono_font);
+	registerTextEdit->setFont(mono_font);
+
+	// To forward scrolling from the list widget to the external scrollbar
+	disasmListWidget->installEventFilter(this);
+
+	// Setup scroll bar
+	verticalScrollBar->setRange(0, INT32_MAX);
+	verticalScrollBar->setSingleStep(8);
+	verticalScrollBar->setPageStep(getLinesInViewport(disasmListWidget));
+	verticalScrollBar->show();
+	connect(verticalScrollBar, &QScrollBar::valueChanged, this, &CPUDebugger::updateDisasm);
+	registerTextEdit->setReadOnly(true);
+
+	connect(goToPCButton, &QPushButton::clicked, this, [&]() {
+		u32 pc = emu->getCPU().getReg(15);
+		verticalScrollBar->setValue(pc);
+	});
+
+	disable();
+	hide();
+}
+
+void CPUDebugger::enable() {
+	enabled = true;
+	auto pc = emu->getCPU().getReg(15);
+
+	disabledOverlay->hide();
+	verticalScrollBar->setValue(pc);
+
+	update();
+}
+
+void CPUDebugger::disable() {
+	enabled = false;
+
+	disabledOverlay->show();
+}
+
+void CPUDebugger::update() {
+	if (enabled) {
+		updateDisasm();
+		updateRegisters();
+	}
+}
+
+void CPUDebugger::updateDisasm() {
+	int currentRow = disasmListWidget->currentRow();
+	disasmListWidget->clear();
+
+	auto [firstLine, lineCount] = getVisibleLineRange(disasmListWidget, verticalScrollBar);
+	const u32 startPC = (firstLine + 3) & ~3;  // Align PC to 4 bytes
+	const u32 endPC = startPC + lineCount * sizeof(u32);
+
+	auto& cpu = emu->getCPU();
+	auto& mem = emu->getMemory();
+	u32 pc = cpu.getReg(15);
+
+	Common::CapstoneDisassembler disassembler(CS_ARCH_ARM, CS_MODE_ARM);
+	std::string disassembly;
+
+	for (u32 addr = startPC; addr < endPC; addr += sizeof(u32)) {
+		if (auto pointer = (u32*)mem.getReadPointer(addr)) {
+			const u32 instruction = *pointer;
+
+			// Convert instruction to byte array to pass to Capstone
+			const std::array<u8, 4> bytes = {
+				u8(instruction & 0xff),
+				u8((instruction >> 8) & 0xff),
+				u8((instruction >> 16) & 0xff),
+				u8((instruction >> 24) & 0xff),
+			};
+
+			disassembler.disassemble(disassembly, pc, std::span(bytes));
+			disassembly = fmt::format("{:08X}     |     {}", addr, disassembly);
+
+			QListWidgetItem* item = new QListWidgetItem(QString::fromStdString(disassembly));
+			if (addr == pc) {
+				item->setBackground(Qt::darkGreen);
+			}
+			disasmListWidget->addItem(item);
+		} else
+			disasmListWidget->addItem(QString::fromStdString(fmt::format("{:08X}     |     ???", addr)));
+	}
+
+    disasmListWidget->setCurrentRow(currentRow);
+}
+
+void CPUDebugger::updateRegisters() {
+	auto& cpu = emu->getCPU();
+	const std::span<u32, 16> gprs = cpu.regs();
+	const std::span<u32, 32> fprs = cpu.fprs();
+	const u32 pc = gprs[15];
+	const u32 cpsr = cpu.getCPSR();
+	const u32 fpscr = cpu.getFPSCR();
+
+	std::string text = "";
+	text.reserve(2048);
+
+	text += fmt::format("PC: {:08X}\nCPSR: {:08X}\nFPSCR: {:08X}\n", pc, cpsr, fpscr);
+
+	text += "\nGeneral Purpose Registers\n";
+	for (int i = 0; i < 10; i++) {
+		text += fmt::format("r{:01d}:     0x{:08X}\n", i, gprs[i]);
+	}
+	for (int i = 10; i < 16; i++) {
+		text += fmt::format("r{:02d}:    0x{:08X}\n", i, gprs[i]);
+	}
+
+	text += "\nFloating Point Registers\n";
+	for (int i = 0; i < 10; i++) {
+		text += fmt::format("f{:01d}:     {:f}\n", i, Helpers::bit_cast<float, u32>(fprs[i]));
+	}
+	for (int i = 10; i < 32; i++) {
+		text += fmt::format("f{:01d}:    {:f}\n", i, Helpers::bit_cast<float, u32>(fprs[i]));
+	}
+
+	registerTextEdit->setPlainText(QString::fromStdString(text));
+}
+
+bool CPUDebugger::eventFilter(QObject* obj, QEvent* event) {
+	// Forward scroll events from the list widget to the scrollbar
+	if (obj == disasmListWidget && event->type() == QEvent::Wheel) {
+		QWheelEvent* wheelEvent = (QWheelEvent*)event;
+
+		int wheelSteps = wheelEvent->angleDelta().y() / 60;
+		int newScrollValue = verticalScrollBar->value() - wheelSteps;
+		newScrollValue = qBound(verticalScrollBar->minimum(), newScrollValue, verticalScrollBar->maximum());
+		verticalScrollBar->setValue(newScrollValue);
+
+		return true;
+	}
+
+	return QWidget::eventFilter(obj, event);
+}
+
+void CPUDebugger::showEvent(QShowEvent* event) {
+	QWidget::showEvent(event);
+
+	enable();
+}
+
+void CPUDebugger::keyPressEvent(QKeyEvent* event) {
+    constexpr usize instructionSize = sizeof(u32);
+
+	if (event->key() == Qt::Key_Up) {
+		verticalScrollBar->setValue(verticalScrollBar->value() - instructionSize);
+	} else if (event->key() == Qt::Key_Down) {
+		verticalScrollBar->setValue(verticalScrollBar->value() + instructionSize);
+	} else {
+		QWidget::keyPressEvent(event);
+	}
+}
+
+void CPUDebugger::resizeEvent(QResizeEvent* event) {
+	QWidget::resizeEvent(event);
+	disabledOverlay->resize(event->size());
+	verticalScrollBar->setPageStep(getLinesInViewport(disasmListWidget));
+
+	update();
+}

src/panda_qt/main_window.cpp

@@ -66,6 +66,7 @@ MainWindow::MainWindow(QApplication* app, QWidget* parent) : QMainWindow(parent)
 	auto cheatsEditorAction = toolsMenu->addAction(tr("Open Cheats Editor"));
 	auto patchWindowAction = toolsMenu->addAction(tr("Open Patch Window"));
 	auto shaderEditorAction = toolsMenu->addAction(tr("Open Shader Editor"));
+	auto cpuDebuggerAction = toolsMenu->addAction(tr("Open CPU Debugger"));
 	auto threadDebuggerAction = toolsMenu->addAction(tr("Open Thread Debugger"));
 	auto dumpDspFirmware = toolsMenu->addAction(tr("Dump loaded DSP firmware"));
 
@@ -74,6 +75,7 @@ MainWindow::MainWindow(QApplication* app, QWidget* parent) : QMainWindow(parent)
 	connect(shaderEditorAction, &QAction::triggered, this, [this]() { shaderEditor->show(); });
 	connect(cheatsEditorAction, &QAction::triggered, this, [this]() { cheatsEditor->show(); });
 	connect(patchWindowAction, &QAction::triggered, this, [this]() { patchWindow->show(); });
+	connect(cpuDebuggerAction, &QAction::triggered, this, [this]() { cpuDebugger->show(); });
 	connect(threadDebuggerAction, &QAction::triggered, this, [this]() { threadDebugger->show(); });
 	connect(dumpDspFirmware, &QAction::triggered, this, &MainWindow::dumpDspFirmware);
 
@@ -94,6 +96,7 @@ MainWindow::MainWindow(QApplication* app, QWidget* parent) : QMainWindow(parent)
 	luaEditor = new TextEditorWindow(this, "script.lua", "");
 	shaderEditor = new ShaderEditorWindow(this, "shader.glsl", "");
 	threadDebugger = new ThreadDebugger(emu, this);
+	cpuDebugger = new CPUDebugger(emu, this);
 
 	shaderEditor->setEnable(emu->getRenderer()->supportsShaderReload());
 	if (shaderEditor->supported) {