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RetroBIOS

BBKEmu

BBKEmu emulates BBK Longman A4980 and BBK Longman A4988. It reads 4 files, 4 of them required: without a required file it does not start games. A required file is needed only by the machines that use it. Each file below cites the line of source code that reads it.

About this profile
Detail Value
Type standalone + libretro
Classification Pure libretro
Source https://github.com/AloysHF/BBKEmu
Version 0.1.0, stated in Cargo.toml
Revision AloysHF/BBKEmu@6641863f6ec5
Profiled 2026-10-26
Profile YAML, JSON
Cores bbkemu
Systems BBK Longman A4980, BBK Longman A4988
Install this emulator's files

For BBKEmu inside RetroArch, EmuDeck or another setup. 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 bbkemu
Platform details

  • memory_map:

    • source_ref: crates/bbkemu-core/src/memory.rs:377-398
    • note: Physical space seen through sixteen 4 KiB bank registers: RAM below 0x8000, 2 MiB flash at 0x200000, 8.BIN at 0x800000, E.BIN at 0xE00000. Reads outside a loaded image return 0x00, and ROM windows ignore writes.
Technical notes

BBK A-series electronic dictionary game emulator written in Rust by AloysHF. The libretro core and the bbk-emu standalone binary share the bbkemu-core crate. A .gam game is 6502 code that calls into the dictionary's OS ROM for LCD, keyboard, audio, timer and file services.

Two ROM images are read from the system directory, in one subdirectory per model: {system}/BBKEmu/<model>/8.BIN, the font ROM mapped at physical 0x800000-0x9FFFFF, and E.BIN, the OS ROM mapped at 0xE00000-0xFFFFFF (crates/bbkemu-libretro/src/lib.rs:186-219, crates/bbkemu-core/src/memory.rs:377-398). The libretro core always loads content as the A4980 model (crates/bbkemu-libretro/src/lib.rs:491-492), so only BBKEmu/A4980/ is ever read from RetroArch. The core also accepts 8.bin, and E.bin or e.bin, when the upper-case name is absent. The Emscripten build used by EmulatorJS looks in the folder of the content and its BBKEmu/<model>/ subfolder as well. Both reads are std::fs::read results taken only when they succeed: a missing file is skipped without any message to the frontend. The image is copied into a 2 MiB zero-filled buffer (crates/bbkemu-core/src/memory.rs:197-209), and nothing checks its size or contents.

Without E.BIN, run_os_init (crates/bbkemu-core/src/emulator.rs:231-252) sets PC to 0x350, reads zeros from the ROM window, never sees _MTCT=0xFE and gives up after 10 million cycles. The bank registers stay unmapped and the game exits at its first OS call. Measured by running run_os_init from bbkemu-core against a dump: 1 092 023 cycles to completion with E.BIN, timeout without it. Without 8.BIN the font window reads as 0x00 and every glyph the OS draws is blank, but execution continues.

The standalone binary takes -8/--rom8 and -e/--rome explicit paths and otherwise reads system/BBKEmu/<model>/8.BIN and E.BIN relative to the working directory, --model 4980 (default) or 4988 selecting the subdirectory (crates/bbkemu/src/main.rs:108-117, crates/bbkemu/src/main.rs:146-170). The A4988 model differs by its flash save-area offset and key layout (crates/bbkemu-core/src/emulator.rs:148-153, crates/bbkemu-libretro/src/lib.rs:640-649).

During init the OS maps its own bank at logical bank D: 0xEA8 for the A4980 OS, 0xE88 for the A4988 OS (crates/bbkemu-core/src/model.rs:11-13). The core never reads that value back: detect_model (crates/bbkemu-core/src/model.rs:37-49) has no caller. The include_bytes! font in crates/bbkemu-core/src/font.rs is not declared in lib.rs and is not compiled. Content arrives through the frontend buffer (need_fullpath = false, crates/bbkemu-libretro/src/lib.rs:429). Save RAM is the first 0x14000 bytes of the emulated flash (crates/bbkemu-libretro/src/lib.rs:861-863).

Files

Section titled “Files”

4 files: 4 required, 0 optional.

In this collection: 4 in repo and 0 missing.

Required

Section titled “Required”

8.BIN required for BBK Longman A4980 in repo

BBK A-series font ROM

  • Path: BBKEmu/A4980/8.BIN
  • Standalone path: system/BBKEmu/A4980/8.BIN
  • System: BBK Longman A4980
  • Read whole from {system}/BBKEmu/A4980/8.BIN, or 8.bin, into the 2 MiB window at physical 0x800000. A missing file is skipped silently, and the window then reads as 0x00 and text drawn through the OS is blank. No size or hash check. Size is the window the image fills.
Source

E.BIN required for BBK Longman A4980 in repo

BBK A-series OS ROM

  • Path: BBKEmu/A4980/E.BIN
  • Standalone path: system/BBKEmu/A4980/E.BIN
  • System: BBK Longman A4980
  • Read whole from {system}/BBKEmu/A4980/E.BIN, or E.bin or e.bin, into the 2 MiB window at physical 0xE00000. The last 256 bytes also serve as the interrupt vector page at 0x0300. A missing file is skipped silently, the OS init loop times out after 10 million cycles and no game runs. No size or hash check. Size is the window the image fills.
Source

8.BIN required for BBK Longman A4988 in repo standalone

BBK A-series font ROM, A4988 slot

  • Standalone path: system/BBKEmu/A4988/8.BIN
  • System: BBK Longman A4988
  • Read by the standalone binary with --model 4988 from system/BBKEmu/A4988/8.BIN relative to the working directory. The libretro core has no model option and never opens this directory.
Source

E.BIN required for BBK Longman A4988 in repo standalone

BBK A-series OS ROM, A4988 slot

  • Standalone path: system/BBKEmu/A4988/E.BIN
  • System: BBK Longman A4988
  • Read by the standalone binary with --model 4988 from system/BBKEmu/A4988/E.BIN relative to the working directory. The libretro core has no model option and never opens this directory.
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.