retroasm - Modern Assembler for Retro Computer Systems

retroasm is a modern, high-performance assembler for retro computer systems, designed to compile assembly language into machine code for classic hardware platforms. It provides both a command-line interface and a Go library API, making it ideal for both standalone development and integration into larger toolchains.

Key Features

Architecture Support

• 6502 CPU - Full support including undocumented opcodes
• Nintendo Entertainment System (NES) - Native target platform with proper memory mapping
• Extensible Architecture - Framework designed for adding Z80 and other retro CPUs

Assembler Compatibility

• asm6 - Compatible with asm6/asm6f assembly syntax
• ca65 - Supports ca65 configuration files and directives
• nesasm - Process nesasm-compatible assembly files
• Multi-format - Single tool for multiple assembly dialects

Advanced Capabilities

• Library API - Use as a Go library for compiler integration
• AST-based Assembly - Direct AST input for programmatic code generation
• Configuration Files - ca65-style configuration for memory layouts
• Modern Go Implementation - Fast, reliable, and maintainable codebase

Quick Start

Installation

Option 1: Download Pre-built Binary Download from Releases and extract to your PATH.

Option 2: Install from Source

go install github.com/retroenv/retroasm/cmd/retroasm@latest

System Requirements:

• Linux: 2.6.32+
• Windows: 10+
• macOS: 10.15 Catalina+

Basic Usage

Simple Assembly:

# Assemble a basic 6502 program
retroasm -o game.nes program.asm

With Configuration:

# Use ca65-style configuration file
retroasm -c memory.cfg -o game.nes main.asm

Command Line Options

usage: retroasm [options] <file to assemble>

  -c string
        assembler config file (ca65 compatible)
  -cpu string
        target CPU architecture: 6502 (default "6502")
  -debug
        enable debug logging with detailed output
  -o string
        output ROM file name (required)
  -q    perform operations quietly (minimal output)
  -system string
        target system: nes (default "nes")

License

This project is licensed under the MIT License - see the LICENSE file for details.