KallistiOS

Independent SDK for the Sega Dreamcast
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Overview

KOS is an unofficial development kit for the SEGA Dreamcast game console with some support for the NAOMI and NAOMI 2 arcade boards.

KOS was developed from scratch over the internet by a group of free software developers and has no relation to the official Sega Katana or Microsoft Windows CE Dreamcast development kits. This has allowed it to fuel a thriving Dreamcast homebrew scene, powering many commercial releases for the platform over the years. It supports a significant portion of the Dreamcast's hardware capabilities and a wide variety of peripherals, accessories, and add-ons for the console, including custom hardware modifications that have been created by the scene.

Despite the console's age, KOS offers an extremely modern, programmer-friendly development environment. Using the latest GCC toolchain, it supports the entirety of C17 and C++20 including their standard libraries, along with support for portions of C23, C++23, Objective-C, and various POSIX APIs. Additionally, KOS-ports offers a rich set of add-on libraries such as SDL, OpenGL, OpenAL, and Lua for the platform.

Features

Core Functionality

Concurrency with Kernel Threads, C11 Threads, C++11 std::thread, POSIX threads
Virtual Filesystem Abstraction
IPv4/IPv6 Network Stack
Dynamically Loaded Libraries and Modules
GDB Debugger Support

Dreamcast Hardware Support

GD-ROM Optical Drive
Low-level 3D PowerVR Graphics
SH4 ASM-Optimized Math Routines
SH4 SCIF Serial I/O
DMA Controller
Flashrom Filesystem
AICA SPU Sound Processor Driver
Cache and Store Queue Management
Timer Peripherals, Real-Time Clock, Watchdog Timer
Performance Counters
MMU Management
BIOS Font Rendering

Peripherals and Accessory Support

Controller, ASCII Pad
Arcade Stick, Twin Stick, Mission Stick
Keyboard
Mouse
Visual Memory Unit
Puru Puru Vibration Pack
Seaman Microphone
Dreameye Webcam
Lightgun
Racing Wheel
Fishing Rod
Samba De Amigo Maracas
Dance Mat
Dial-up Modem
Broadband Adapter
LAN Adapter
VGA Adapter
SD Card Reader

Hardware Modification Support

IDE Hard Drive
32MB RAM Upgrade
Custom BIOS Flashroms

Getting Started

A beginner's guide to development for the Sega Dreamcast along with detailed instructions for installing KOS and the required toolchains can be found on the Dreamcast Wiki. Additional documentation can be found in the docs folder.

Examples

Once you've set up the environment and are ready to begin developing, a good place to start learning is the examples directory, which provides demos for the various KOS APIs and for interacting with the Dreamcast's hardware. Examples include:

Hello World
Console Input/Output
Assertions, stacktraces, threading
Drawing directly to the framebuffer
Rendering with OpenGL
Rendering with KGL
Rendering with KOS PVR API
Texturing with libPNG
Bump maps, modifier volumes, render-to-texture PVR effects
Audio playback on the ARM SPU
Audio playback using SDL Audio
Audio playback using OGG, MP3, and CDDA
Querying controller input
Querying keyboard input
Querying mouse input
Querying lightgun input
Accessing the VMU filesystem
Accessing the SD card filesystem
Networking with the modem, broadband adapter, and LAN adapter
Taking pictures with the DreamEye webcam
Reading and Writing to/from ATA devices
Testing 32MB RAM hardware mod
Interactive Lua interpreter terminal

Resources

Dreamcast Wiki: Large collection of tutorials and articles for beginners
Simulant Discord Chat: Home to the official Discord channel of KOS
DCEmulation Forums: Goldmine of Dreamcast development information and history
IRC Channel: irc.libera.chat #dreamcastdev

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