Altirra vs Atari800

Altirra is a Windows emulator for 8-bit Atari computers, covering the Atari 400/800, 1200XL, 600/800XL, 130XE, XEGS and 5200. It provides cycle-exact handling of documented hardware and models undocumented behavior, including DMA timing and undocumented 6502 instructions. Supported files include ATR, ATX, ATZ, DCM, XFD, PRO, ARC, BAS, ROM, BIN, A52, CAS and SAP. Reimplemented operating-system, BASIC and handler ROMs are included, while real Atari ROM images can be supplied for compatibility. The emulator models memory and cartridge expansions, PBI devices, modems and 65C02/65C816 accelerators. Disk options include accelerated loading, realistic timing, sounds and drive CPU emulation. Its debugger offers source stepping, breakpoints, watchpoints, history and profiling. Recording, a cheat trainer, disk browsing and text copy/paste are also included. Altirra is free under GPL version 2 for Windows 7 or later.

Atari800 emulates Atari 8-bit computer systems and the Atari 5200 game console. It supports cycle-exact emulation of the 6502 processor and the NMI, POKEY, ANTIC and GTIA components. The emulator handles ATR, XFD, DCM, ATR.GZ and XFD.GZ disk images, with up to eight emulated drives. It can load Atari executable files and BASIC programs, emulate cassette tapes, and save files to the host computer through the H: device. Users can connect real joysticks or emulate paddles, light pens, light guns, mice and trackballs. Atari800 can save screen snapshots as PCX or PNG and write sound output to WAV files. It runs on Linux, Windows, macOS and Android; source and binary packages are available through GitHub releases, with Linux package instructions for Debian and Fedora. The project describes Atari800 as freely distributable, with source under GPL version 2. Its release notes describe NetSIO and FujiNet support for network SIO over UDP. Atari800 is written in C, and a BIOS is required.