Qt: Initial CPU debugger widget implementation

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

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();
+}