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RetroBIOS

ProSystem

ProSystem emulates Atari 7800. It reads 2 files, none of them required: it starts games without them.

About this profile
Detail Value
Type libretro
Classification Community fork
Source https://github.com/libretro/prosystem-libretro
Upstream https://github.com/gstanton/ProSystem1_3
Version 1.3e, stated in core/libretro.c
Revision libretro/prosystem-libretro@8a88014287c7
Profiled 2026-03-24
Profile YAML, JSON
Cores prosystem
Systems Atari 7800
Install this emulator's files

The installer finds your setup and its BIOS folder, then downloads only the files this emulator reads there and checks each one.

Open the Start menu. Type PowerShell and open it. Paste the line. Press Enter.

PowerShell
&([scriptblock]::Create((irm https://abdess.github.io/retrobios/i.ps1))) --emulator prosystem
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 one firmware, the U BIOS. The code also opens the E BIOS for PAL cartridges (core/libretro.c:581-582).

Files

Section titled “Files”

2 files: 0 required, 2 optional. 2 have an HLE fallback.

In this collection: 2 in repo and 0 missing.

Optional

Section titled “Optional”

7800 BIOS (U).rom optional in repo HLE fallback

NTSC/US BIOS, loaded when cartridge_region != REGION_PAL

Source

7800 BIOS (E).rom optional in repo HLE fallback

PAL/EU BIOS, loaded when cartridge_region == REGION_PAL

Source

Next steps

Section titled “Next steps”
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Maintained by Abdess on GitHub. Report a problem.

Packs from release v2026.10.10, .

MIT for the tooling and metadata. BIOS and firmware files are third-party system software, preserved for personal backup, archival and interoperability.