Original Apollo 11 Guidance Computer (AGC) source code for the command and lunar modules.

Microsoft BASIC for 6502 Microprocessor - Version 1.1

The development kit for over a hundred z80 family machines - c compiler, assembler, linker, libraries.

Incompatible Timesharing System

#FreeGEOS source codes. The offical home of the PC/GEOS operating system technology. For personal computing fans. For all developers and assembly lovers. For YOU!

An Operating System for Z80 computers, written in assembly

Source code of GEOS 2.0 for the Commodore 64 and 128

Fully documented source code for the classic game Elite on the Commodore 64

System Software for Z80/Z180/Z280 Computers

Historical source code for Infocom's Z-machine interpreters

CP/M for the 6502

Code for the 6502 microprocessor, mostly for the Replica 1 computer.

A large repository of Atari ST (and family) source code

A project to create unencumbered open-source ROMs for use on selected retro computers

Ray Tracer in 483 bytes (x86 boot sector)

Homebrew 65C02 computer on a backplane

Data compressor for 8-bit computers and low-end platforms

Proto Language AsSeMbler for All (formerly Apple)

A Slack client for the Commodore 64

A workbench for developing 6502 code.

Complete package of AmiBlitz3 including all sources.

Sample source code games Atari 2600

Tools for manipulating Apple II dos33 filesystems

GUI64 is a graphical user interface for the Commodore 64.

IP65 - a TCP/IP stack for 6502 based computers

A Z-machine interpreter for the Commodore 64 and similar computers

Ultima IV Remastered for the C64

HippoPlayer - a module player for the classic Amiga

Neo6502 Modern Retro Computer with W65C02S processor and RP2040 memory and peripherals emulator