WineRosetta2

A lightweight JIT (Just-In-Time) binary translator specifically designed to address issues with World of Warcraft Classic versions running in Wine on Apple Silicon Macs (M1, M2, M3, M4) by handling problematic x86 instructions that cause conflicts with Rosetta 2 translation. Despite these improvements, performance remains significantly limited, with users typically experiencing around 5 FPS, making gameplay still quite challenging.

Introduction

This implementation functions as a simple JIT binary translator that targets specific problematic instructions. While the original design solely relied on a Vectored Exception Handler to catch and handle illegal instructions at runtime, this enhanced version adds proactive patching:

1. JIT Binary Translation: It identifies and translates problematic instructions on-the-fly
2. Upfront Scanning: It pre-patches known problematic instructions during module loading to avoid unnecessary exceptions
3. Fallback Exception Handling: It maintains a VEH handler to catch any instructions missed by the initial scan
4. Memory Efficient: Targeted approach that only modifies specific problematic instructions rather than performing full code translation

This approach is minimally invasive while providing the necessary fixes to run World of Warcraft Classic on Apple Silicon Macs through Wine.

Overview

WineRosetta2 is a dynamic binary translator that attempts to address problematic x86 instructions that cause issues when running World of Warcraft Classic through Wine on Apple Silicon Macs using Rosetta 2.

While initial development focused on ARPL and FCOMP instructions, testing has revealed that the actual problematic instructions may be different or more complex than originally thought. This tool represents an experimental approach to identifying and handling instructions that cause translation conflicts between Wine and Rosetta 2.

These unidentified problematic instructions can cause crashes or illegal instruction exceptions when translated by Rosetta 2 on Apple Silicon processors.

The tool works by:

1. Pre-scanning executable memory to patch known problematic instructions
2. Installing a Vectored Exception Handler (VEH) to catch and emulate instructions that weren't patched ahead of time

Usage

Installation and Usage

1. Compile both the EXE and DLL versions of WineRosetta2
2. Place both WineRosetta2.exe and WineRosetta2.dll in the same directory as your wow.exe executable
3. Run WineRosetta2.exe (no command-line arguments are needed)

The tool will automatically locate and launch the wow.exe file in the same directory. It does not accept any command-line arguments.

Important: Both the EXE and DLL files must be present in the same directory for proper functionality.

This is particularly useful for World of Warcraft Classic versions running on Apple Silicon Macs (M1-M4) through Wine, where Rosetta 2 translation issues can cause crashes.

How It Works

WineRosetta2 uses two approaches to handle problematic instructions:

1. Proactive Optimization: On startup, it scans all loaded modules and patches problematic instructions.
2. Reactive Handling: It installs a Vectored Exception Handler to catch illegal instruction exceptions and emulate them at runtime.

Building

The project must be built as both a standalone launcher and as a DLL:

• Launcher: Build without the BUILD_AS_DLL flag
• DLL: Build with the BUILD_AS_DLL flag

You need to compile both versions and place them in the same directory as your WoW executable.

Compilation Commands

Use the following commands to compile both versions on a Linux system with MinGW:

For the EXE:

i686-w64-mingw32-g++ -o winerosetta2.exe winerosetta2.cpp -static -static-libgcc -static-libstdc++ -std=c++11 -Wall -O2

For the DLL:

i686-w64-mingw32-g++ -o winerosetta2.dll winerosetta2.cpp -shared -DBUILD_AS_DLL -static -static-libgcc -static-libstdc++ -std=c++11 -Wall -O2

This will create statically linked 32-bit Windows binaries that can be used with Wine.

Credits

This implementation is based on the work by Lifeisawful, with modifications and optimizations.

License

The original WineRosetta project by Lifeisawful is licensed under the MIT license.