libgodc - Go runtime for Sega Dreamcast

Replaces the standard Go runtime with one designed for the Dreamcast's constraints: memory 16MB RAM, CPU single-core SH-4, no operating system. Provides garbage collection, goroutines, channels, and the core runtime functions.

Quick Start

Prerequisites: Go 1.25.3+, make, and git must be installed.

go install github.com/drpaneas/godc@latest
godc setup
godc doctor # to check (optional)

Note: The godc CLI tool is a separate project that handles toolchain setup and builds.

Create and run a project:

mkdir myproject && cd myproject
godc init
# write your main.go and other *.go files
godc build
godc run

See the Quick Start Guide for your first program.

Documentation

📚 Full Documentation

• Installation — Setup and configuration
• Quick Start — First program walkthrough
• Design — Runtime architecture
• Effective Dreamcast Go — Best practices
• KOS Wrappers — Calling C from Go
• Limitations — What doesn't work

Performance

The repo includes tests/bench_architecture.go for measuring runtime behavior on Dreamcast hardware.

Benchmark	What it reports
gosched	Nanoseconds per yield
Buffered channel	Nanoseconds per buffered operation
Context switch	Nanoseconds per goroutine switch
Unbuffered channel	Nanoseconds per roundtrip
Goroutine spawn	Nanoseconds per spawn/run cycle
GC pause	Microseconds per forced collection across retained sizes from 32 KB to 1 MB
Memory layout	Stack size, context size, header size, and large-object threshold

Run tests/bench_architecture.elf on your hardware for current numbers.

Examples

The examples/ directory contains working programs:

• hello — Minimal program (debug output)
• hello_screen — Hello World on screen using BIOS font
• blue_screen — Minimal graphics
• input — Controller input
• goroutines — Concurrent bouncing balls
• channels — Producer/consumer pattern
• timer — Frame-rate independent animation
• bfont — BIOS font rendering
• filesystem — Directory browser
• vmu — VMU LCD and buzzer
• brkout — Breakout clone (GPL v2, port of Jim Ursetto's original)
• platformer — Side-scrolling platformer
• pong — Pong clone with 1P/2P mode, particle effects, and AI

License

BSD 3-Clause License. See LICENSE for details.