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# ProSystem - RetroBIOS

Type | libretro
Classification | community_fork
Source | https://github.com/libretro/prosystem-libretro
Upstream | https://github.com/gstanton/ProSystem1_3
Version | 1.3e
Profiled | 2026-03-24
Cores | prosystem
Systems | atari-7800

Technical notes

Atari 7800 emulator by Greg Stanton, ported to libretro by community contributors. The upstream is a Windows-only application with a single user-configured BIOS path. The libretro port adds automatic region-based BIOS selection: PAL carts get (E), everything else gets (U).

Region is read from cartridge header byte 57 (core/Cartridge.c:214) or overridden by the internal database (core/Database.c:1739-1757).

Both BIOS files are optional. The core runs without them but some titles have compatibility issues (startup encryption check). bios_Store() maps the BIOS into ROM at address (65536 - bios_size).

No core option controls BIOS loading. If the file exists in the system directory, it is loaded automatically. No hash or size validation is performed on the BIOS file.

The .info declares firmware_count=1 (U only), missing the PAL BIOS.

2 files | 0 required, 2 optional | 2 in repo, 0 missing | 2 with HLE fallback

`7800 BIOS (U).rom` -optional, HLE available : NTSC/US BIOS, loaded when cartridge_region != REGION_PAL

- System: atari-7800
- Size: 4.0 KB
- Source: `core/libretro.c:585`
- Platforms: lakka, recalbox, retroarch, retrobat, retrodeck, retropie

`7800 BIOS (E).rom` -optional, HLE available : PAL/EU BIOS, loaded when cartridge_region == REGION_PAL

- System: atari-7800
- Size: 16.0 KB
- Source: `core/libretro.c:583`
- Platforms: lakka, recalbox, retroarch, retrobat, retrodeck, retropie

Generated on 2026-03-25T14:56:43Z