360μ (360mu)

An experimental Xbox 360 emulator for Android

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⚠️ Project Status

360μ is in early development. It cannot run commercial games yet. The emulator boots and executes game code, but games currently get stuck during initialization due to incomplete GPU command processing.

Current State (December 2024)

Component	Status	Notes
Memory System	✅ Working	512MB main RAM, fastmem optimization
XEX Loader	✅ Working	Loads encrypted/compressed Xbox 360 executables
CPU Interpreter	✅ Working	Full PowerPC instruction set
CPU JIT	✅ Working	PowerPC to ARM64 translation, ~80% coverage
VMX128 (SIMD)	🟡 Partial	Basic vector instructions
Kernel HLE	✅ Working	~60 syscalls implemented
Thread Scheduler	✅ Working	1:1 threading model (each guest thread = host thread)
GPU (Vulkan)	🟡 Partial	Initialized, waiting for ring buffer commands
Audio (XMA)	🟡 Partial	Decoder present, not receiving data
File System	✅ Working	ISO mounting, VFS layer

Recent Progress (December 2024)

Major Threading Fixes Completed:

1. ✅ JIT syscall PC advancement - Fixed infinite syscall loop
2. ✅ Context synchronization - JIT and HLE now share context properly
3. ✅ Address translation - Consistent 0x1FFFFFFF masking across JIT and HLE
4. ✅ Thread-local storage - Proper thread identification in multi-threaded mode
5. ✅ 1:1 threading model - Each guest thread has its own host thread

Current Blocker: Games progress past initial boot but get stuck in secondary polling loops. The GPU ring buffer is not yet receiving commands from the game.

See NEXT_STEPS.md for the detailed roadmap.

🎯 Goals

• Create a performant Xbox 360 emulator for modern Android devices
• Leverage Vulkan for GPU emulation on mobile
• Use JIT recompilation for CPU emulation (PowerPC to ARM64)
• Support flagship devices (Snapdragon 8 Gen 2+, Dimensity 9000+)

📋 Requirements

Minimum

• Android 10 (API 29)
• ARM64 processor
• Vulkan 1.1 support
• 6GB RAM

Recommended

• Android 12+
• Snapdragon 8 Gen 2 or newer
• 8GB+ RAM
• 30GB+ free storage

🏗️ Building

Prerequisites

• Android Studio Hedgehog (2023.1.1) or newer
• Android NDK r26 or newer
• CMake 3.22+
• JDK 17

Build Steps

# Clone the repository
git clone https://github.com/yourname/360mu.git
cd 360mu

# Open in Android Studio or build from command line
cd android
./gradlew assembleDebug

# Install on device
adb install -r app/build/outputs/apk/debug/app-debug.apk

📁 Project Structure

360mu/
├── android/              # Android app (Kotlin + Jetpack Compose)
│   └── app/src/main/
│       ├── java/         # Kotlin UI code
│       └── cpp/          # JNI bridge
├── native/               # Emulator core (C++)
│   └── src/
│       ├── cpu/          # PowerPC Xenon emulation
│       │   ├── xenon/    # Interpreter, CPU state, threading
│       │   ├── jit/      # ARM64 JIT compiler
│       │   └── vmx128/   # Vector unit (SIMD)
│       ├── gpu/          # ATI Xenos emulation
│       │   └── xenos/    # Vulkan backend, command processor
│       ├── apu/          # Audio processing (XMA)
│       ├── kernel/       # Xbox kernel HLE
│       │   └── hle/      # High-level syscall emulation
│       ├── memory/       # Memory management, fastmem
│       ├── loader/       # XEX/ISO loading
│       └── vfs/          # Virtual file system
├── shaders/              # Vulkan shaders (GLSL)
└── docs/                 # Documentation
    ├── architecture/     # Architecture documentation
    ├── issues/           # Known issues (historical)
    └── tasks/            # Development task tracking

🗺️ Roadmap

See DEVELOPMENT_PLAN.md for the detailed technical plan.

Phase 1: Foundation ✅

• Project setup
• Memory system (512MB + fastmem)
• XEX loader (encryption, compression, imports)
• CPU interpreter (full PPC instruction set)

Phase 2: CPU JIT ✅

• JIT framework (ARM64 emitter)
• Block cache with invalidation
• ~80% PPC instruction coverage
• VMX128 JIT (currently interpreted)

Phase 3: Kernel & Threading ✅

• Syscall dispatch
• Thread creation/scheduling
• 1:1 threading model
• Context synchronization
• Thread-local storage
• Additional synchronization primitives

Phase 4: GPU 🟡 (Current Focus)

• Vulkan backend initialization
• Ring buffer command processing ← Current blocker
• Shader translator
• eDRAM emulation

Phase 5: Audio & I/O

• XMA decoder framework
• Audio output integration
• Controller input
• Save states

🐛 Debugging

# View emulator logs
adb logcat -s 360mu:* 360mu-cpu:* 360mu-jit:* 360mu-kernel:*

# Check GPU status
adb logcat -d | grep "GPU\|ring buffer"

# Check thread creation
adb logcat -d | grep "Created thread"

# Check syscall dispatch
adb logcat -d | grep "First call to syscall"

# Check for unimplemented syscalls
adb logcat -d | grep "UNIMPLEMENTED"

🤝 Contributing

Contributions are welcome! Please read our contributing guidelines before submitting PRs.

Areas needing help:

• GPU command processing - Ring buffer parsing, PM4 packets
• Shader translation - Xenos shaders to SPIR-V
• PowerPC JIT optimization - VMX128, missing instructions
• Additional syscall implementations
• Game compatibility testing

📚 Resources

• Xbox 360 Architecture
• Xenia Emulator (Reference implementation)
• Free60 Wiki
• Xbox Dev Wiki

⚖️ Legal

This emulator does not include any Xbox 360 system software or games. Users must legally own any games they wish to emulate.

360μ is not affiliated with Microsoft Corporation.

📜 License

360μ is licensed under the GNU General Public License v3.0. See LICENSE for details.

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Made with ❤️ for the emulation community