Altirra
2009 Open source · GPL-2.0 Downloadable
Altirra is a cycle-exact emulator of the Atari 400/800, 1200XL, 600/800XL, 130XE, XEGS and 5200 systems, prized for its accuracy of both documented and undocumented hardware behaviour. It ships with its own open-source AltirraOS and BASIC kernel so it can run software without original Atari ROMs, and includes an extensive built-in debugger.
Runs on: Windows