Setup

This guide covers installing the R65 compiler toolchain and creating your first SNES project.

Prerequisites

R65 requires:

• Python 3.8+ (3.10 or later recommended)
• WLA-DX assembler and linker (wla-65816, wlalink)
• Git (to clone the repository)

Optional:

• Mesen or bsnes emulator (to run compiled ROMs)
• make (to use the generated Makefiles)

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Step 1: Install Python

Verify your Python version:

python3 --version   # Must be 3.8 or higher

If Python is not installed or too old:

• Ubuntu/Debian: sudo apt install python3 python3-pip
• Fedora: sudo dnf install python3 python3-pip
• macOS: brew install python or download from python.org
• Windows: Download from python.org (check "Add to PATH" during install)

Step 2: Install WLA-DX

WLA-DX is the assembler and linker that converts R65 compiler output into SNES ROMs.

macOS (Homebrew):

brew install wla-dx

Linux (build from source):

git clone https://github.com/vhelin/wla-dx.git
cd wla-dx
mkdir build && cd build
cmake ..
cmake --build . --config Release
sudo cmake --install .

Pre-built binaries:

Download from the WLA-DX releases page and place wla-65816 and wlalink on your PATH.

Verify installation:

wla-65816       # Should print version banner (v10.x)
wlalink         # Should print usage info

Step 3: Install R65

Clone the repository and install in development mode:

git clone https://github.com/neutron-emulation/R65.git
cd R65
pip install -e .

This installs three command-line tools:

Command	Purpose
r65c	Compiler (R65 source to WLA-DX assembly)
r65x	Project tool (scaffolding, asset generation)

Verify installation:

r65c --help
r65x --help

Development dependencies (optional)

To run the test suite:

pip install -e ".[dev]"
python -m pytest r65/tests/

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Step 4: Create a project

Use r65x init to scaffold a new SNES project:

r65x init --platform snes my_game
cd my_game

This creates:

my_game/
├── src/
│   ├── main.r65            # Entry point
│   └── lib/                # Standard library (copied from stdlib/)
│       ├── 65816.r65
│       ├── sneslib.r65
│       ├── math.r65
│       └── ...
├── build/                  # Compiled output (created on first build)
├── Makefile                # Build system
└── README.md

The generated main.r65 is a minimal SNES program:

#[snesrom(name="MY_GAME")]

include!("lib/65816.r65")
include!("lib/sneslib.r65")
include!("lib/math.r65")

#[bank(0)]

#[interrupt(nmi)]
fn nmi_handler() {
    clear_nmi!()
}

#[entry]
fn main() -> ! {
    snes_init();
    INIDISP = 0x0;

    loop {

    }
}

Step 5: Build

make

The build pipeline runs three stages:

1. Compile — r65c translates R65 source to WLA-DX assembly (.asm)
2. Assemble — wla-65816 assembles the output into an object file (.o)
3. Link — wlalink links the object into a SNES ROM (.smc)

The final ROM is placed in build/MY_GAME.smc.

Build targets

Target	Description
make	Build the ROM (default)
make run	Build and launch in emulator (Mesen, bsnes, or higan)
make clean	Remove all build artifacts
make syntax	Compile R65 to assembly only (no ROM)
make debug	Rebuild from scratch with verbose output
make install-deps	Install WLA-DX via Homebrew

Step 6: Run

Open the ROM in a SNES emulator:

make run    # Auto-detects Mesen, higan, or bsnes

Or open build/MY_GAME.smc directly in your emulator of choice.

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Next steps

• Compiler Reference — all r65c flags, optimization levels, diagnostic dumps, build pipeline, and debugging with Mesen
• Project Tools Reference — r65x commands for project scaffolding, font generation, data compression, and bitmap-to-tile conversion