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# Fuse - RetroBIOS

Type | libretro
Classification | community_fork
Source | https://github.com/libretro/fuse-libretro
Upstream | https://sourceforge.net/projects/fuse-emulator/
Version | 1.6.0
Profiled | 2026-03-23
Cores | fuse
Systems | sinclair-zxspectrum

Platform details

bios_mapping: - source_ref: src/compat/file.c:55-89, 129-223 - notes: ROM resolution order in compat_file_open():

1. Check mem_entries[] (18 embedded ROMs compiled as .h arrays)

2. If not found, try {system_dir}/fuse/{filename} on filesystem The path is constructed by concatenating system_dir + "/fuse" + path where path includes the leading slash from fuse's internal path.

   embedded_roms: - source_ref: src/compat/file.c:55-73 - notes: 18 ROMs embedded in the binary via .h headers generated from .rom files: 48.rom, 128-0.rom, 128-1.rom, plus2-0.rom, plus2-1.rom, plus3-0/1/2/3.rom, plus3e-0/1/2/3.rom, se-0.rom, se-1.rom, tc2048.rom, tc2068-0.rom, tc2068-1.rom. disciple.rom, plusd.rom, speccyboot-1.4.rom are present in the repo fuse/roms/ directory but NOT in mem_entries[], so they are loaded from the filesystem only.

   machine_rom_map: - source_ref: fuse/settings.c:209-260, fuse/machines/*.c - notes: Spectrum 16K: 48.rom (1 ROM) Spectrum 48K: 48.rom (1 ROM) Spectrum 48K NTSC: 48.rom (1 ROM) Spectrum 128K: 128-0.rom, 128-1.rom (2 ROMs) Spectrum +2: plus2-0.rom, plus2-1.rom (2 ROMs) Spectrum +2A: plus3-0.rom, plus3-1.rom, plus3-2.rom, plus3-3.rom (4 ROMs) Spectrum +3: plus3-0.rom, plus3-1.rom, plus3-2.rom, plus3-3.rom (4 ROMs) Spectrum +3e: plus3e-0/1/2/3.rom (4 ROMs) Spectrum SE: se-0.rom, se-1.rom (2 ROMs) Timex TC2048: tc2048.rom (1 ROM) Timex TC2068: tc2068-0.rom, tc2068-1.rom (2 ROMs) Timex TS2068: tc2068-0.rom, tc2068-1.rom (2 ROMs, same files) Pentagon 128K: 128p-0.rom, 128p-1.rom, trdos.rom (3 ROMs) Pentagon 512K: 128p-0.rom, 128p-1.rom, trdos.rom, gluck.rom (4 ROMs) Pentagon 1024: 128p-0.rom, 128p-1.rom, trdos.rom, gluck.rom (4 ROMs) Scorpion 256K: 256s-0.rom, 256s-1.rom, 256s-2.rom, 256s-3.rom (4 ROMs)

   rom_copyright: - source_ref: fuse/roms/README.copyright - notes: Most ROMs are copyright Amstrad. Amstrad allows free distribution but retains copyright. Selling ROMs standalone is not permitted. SE ROMs are GPLv2+. DISCiPLE/+D ROMs are copyright Datel, distribution allowed. SpeccyBoot ROM is MIT licensed.

Technical notes

Fuse (Free Unix Spectrum Emulator) ported to libretro. Emulates the ZX Spectrum family: 16K, 48K, 48K NTSC, 128K, +2, +2A, +3, +3e, SE, Timex TC2048, TC2068, TS2068, Pentagon 128K/512K/1024, and Scorpion 256K.

ROM loading is in src/compat/file.c:91-118. The core first checks an internal table of embedded ROMs (mem_entries[]). If the ROM filename is not found there, it falls back to the filesystem at {system_dir}/fuse/{rom_filename} (file.c:160-175).

Embedded ROMs cover 48K-family, 128K, +2, +3, +3e, SE, TC2048, TC2068. Pentagon, Scorpion, and peripheral ROMs are NOT embedded and must be placed in {system_dir}/fuse/ by the user.

Default ROM filenames are set in fuse/settings.c:209-260. Each machine type loads its ROMs during reset via machine_load_rom() calls in fuse/machines/*.c files. All ROMs are size-validated at load time (fuse/machine.c:289).

The +2A reuses the +3 ROMs (plus3-0/1/2/3.rom) per settings.c:234-237. The TS2068 reuses TC2068 ROMs (tc2068-0/1.rom) per settings.c:257-258. Spectrum 16K uses 48.rom per settings.c:211.

Upstream FUSE 1.7.0 has SP0256 speech chip (sp0256-al2.rom) and Currah uSpeech (uspeech.rom) peripherals not ported to libretro.

37 files | 8 required, 29 optional | 0 in repo, 37 missing | 18 with HLE fallback

`fuse/48.rom` -optional, HLE available, missing from repo

- System: sinclair-zxspectrum
- Size: 16.0 KB
- SHA1: `5ea7c2b824672e914525d1d5c419d71b84a426a2`
- MD5: `4c42a2f075212361c3117015b107ff68`
- Validation: size
- Source: `fuse/settings.c:211-212, fuse/machines/spec48.c:76`
- Spectrum 48K ROM. Also used for 16K and 48K NTSC. Embedded in core.

`fuse/128-0.rom` -optional, HLE available, missing from repo

- System: sinclair-zxspectrum
- Size: 16.0 KB
- SHA1: `4f4b11ec22326280bdb96e3baf9db4b4cb1d02c5`
- MD5: `b4d2692115a9f2924df92a3cbfb358fb`
- Validation: size
- Source: `fuse/settings.c:209, fuse/machines/spec128.c:70`
- Spectrum 128K ROM 0 (editor). Embedded in core.

`fuse/128-1.rom` -optional, HLE available, missing from repo

- System: sinclair-zxspectrum
- Size: 16.0 KB
- SHA1: `80080644289ed93d71a1103992a154cc9802b2fa`
- MD5: `6e09e5d3c4aef166601669feaaadc01c`
- Validation: size
- Source: `fuse/settings.c:210, fuse/machines/spec128.c:73`
- Spectrum 128K ROM 1 (48 BASIC). Embedded in core.

`fuse/plus2-0.rom` -optional, HLE available, missing from repo

- System: sinclair-zxspectrum
- Size: 16.0 KB
- SHA1: `72703f9a3e734f3c23ec34c0727aae4ccbef9a91`
- MD5: `4ed7af4636308b8a48d7a35e6c5b546b`
- Validation: size
- Source: `fuse/settings.c:232, fuse/machines/specplus2.c:70`
- Spectrum +2 ROM 0. Embedded in core.

`fuse/plus2-1.rom` -optional, HLE available, missing from repo

- System: sinclair-zxspectrum
- Size: 16.0 KB
- SHA1: `de8b0d2d0379cfe7c39322a086ca6da68c7f23cb`
- MD5: `b3db95931cc844efaeb82db9c171b9f3`
- Validation: size
- Source: `fuse/settings.c:233, fuse/machines/specplus2.c:73`
- Spectrum +2 ROM 1. Embedded in core.

`fuse/plus3-0.rom` -optional, HLE available, missing from repo

- System: sinclair-zxspectrum
- Size: 16.0 KB
- SHA1: `e319ed08b4d53a5e421a75ea00ea02039ba6555b`
- MD5: `9833b8b73384dd5fa3678377ff00a2bb`
- Validation: size
- Source: `fuse/settings.c:234,238, fuse/machines/specplus3.c:197`
- Spectrum +3 ROM 0. Also used for +2A. Embedded in core.

`fuse/plus3-1.rom` -optional, HLE available, missing from repo

- System: sinclair-zxspectrum
- Size: 16.0 KB
- SHA1: `c9969fc36095a59787554026a9adc3b87678c794`
- MD5: `0f711ceb5ab801b4701989982e0f334c`
- Validation: size
- Source: `fuse/settings.c:235,239, fuse/machines/specplus3.c:200`
- Spectrum +3 ROM 1. Also used for +2A. Embedded in core.

`fuse/plus3-2.rom` -optional, HLE available, missing from repo

- System: sinclair-zxspectrum
- Size: 16.0 KB
- SHA1: `22e50c6ba4157a3f6a821bd9937cd26e292775c6`
- MD5: `3b6dd659d5e4ec97f0e2f7878152c987`
- Validation: size
- Source: `fuse/settings.c:236,240, fuse/machines/specplus3.c:203`
- Spectrum +3 ROM 2. Also used for +2A. Embedded in core.

`fuse/plus3-3.rom` -optional, HLE available, missing from repo

- System: sinclair-zxspectrum
- Size: 16.0 KB
- SHA1: `65f031caa8148a5493afe42c41f4929deab26b4e`
- MD5: `a148bcc575e51389e84fdf5d555c3196`
- Validation: size
- Source: `fuse/settings.c:237,241, fuse/machines/specplus3.c:206`
- Spectrum +3 ROM 3. Also used for +2A. Embedded in core.

`fuse/plus3e-0.rom` -optional, HLE available, missing from repo

- System: sinclair-zxspectrum
- Size: 16.0 KB
- SHA1: `649fbd233490bf58b35350b0123d36caaaa011eb`
- MD5: `bc123f625e245c225f92ef05933ed134`
- Validation: size
- Source: `fuse/settings.c:242, fuse/machines/specplus3e.c:70`
- Spectrum +3e ROM 0. Embedded in core.

`fuse/plus3e-1.rom` -optional, HLE available, missing from repo

- System: sinclair-zxspectrum
- Size: 16.0 KB
- SHA1: `f12198108cbb14de4f03c6695bc16d08c85ee214`
- MD5: `617364264c587d20c9fc4746c29679f2`
- Validation: size
- Source: `fuse/settings.c:243, fuse/machines/specplus3e.c:73`
- Spectrum +3e ROM 1. Embedded in core.

`fuse/plus3e-2.rom` -optional, HLE available, missing from repo

- System: sinclair-zxspectrum
- Size: 16.0 KB
- SHA1: `773633dce5ba323a9e00d9d0f9e4d8c295df7c87`
- MD5: `c363e95dcd0a90e6e7f847e6e47e0179`
- Validation: size
- Source: `fuse/settings.c:244, fuse/machines/specplus3e.c:76`
- Spectrum +3e ROM 2. Embedded in core.

`fuse/plus3e-3.rom` -optional, HLE available, missing from repo

- System: sinclair-zxspectrum
- Size: 16.0 KB
- SHA1: `65f031caa8148a5493afe42c41f4929deab26b4e`
- MD5: `a148bcc575e51389e84fdf5d555c3196`
- Validation: size
- Source: `fuse/settings.c:245, fuse/machines/specplus3e.c:79`
- Spectrum +3e ROM 3. Same as plus3-3.rom. Embedded in core.

`fuse/se-0.rom` -optional, HLE available, missing from repo

- System: sinclair-zxspectrum
- Size: 16.0 KB
- SHA1: `8608328d7dd66602a4846f046b24fed500f7d828`
- MD5: `fb3f86eb1e5a695d9c50c124e7cfb875`
- Validation: size
- Source: `fuse/settings.c:251, fuse/machines/spec_se.c:89`
- Spectrum SE ROM 0. Embedded in core.

`fuse/se-1.rom` -optional, HLE available, missing from repo

- System: sinclair-zxspectrum
- Size: 16.0 KB
- SHA1: `3be5de57dd3bd0a9d15c57cabe9179afe2906a52`
- MD5: `88de4a3129086f34bb9ca559acc51e6c`
- Validation: size
- Source: `fuse/settings.c:252, fuse/machines/spec_se.c:92`
- Spectrum SE ROM 1. Embedded in core.

`fuse/tc2048.rom` -optional, HLE available, missing from repo

- System: sinclair-zxspectrum
- Size: 16.0 KB
- SHA1: `febb2d495b6eda7cdcb4074935d6e9d9f328972d`
- MD5: `9dd7ecf784a6c04265c073c236f5fadb`
- Validation: size
- Source: `fuse/settings.c:254, fuse/machines/tc2048.c:80`
- Timex TC2048 ROM. Embedded in core.

`fuse/tc2068-0.rom` -optional, HLE available, missing from repo

- System: sinclair-zxspectrum
- Size: 16.0 KB
- SHA1: `1446cb2780a9dedf640404a639fa3ae518b2d8aa`
- MD5: `55d462fccc6c536037404ef4ced08bec`
- Validation: size
- Source: `fuse/settings.c:255,257, fuse/machines/tc2068.c:138`
- Timex TC2068 ROM 0. Also used for TS2068. Embedded in core.

`fuse/tc2068-1.rom` -optional, HLE available, missing from repo

- System: sinclair-zxspectrum
- Size: 8.0 KB
- SHA1: `7e265a2c1f621ed365ea23bdcafdedbc79c1299c`
- MD5: `575d203c6e15e679fba0b73f854ec7a2`
- Validation: size
- Source: `fuse/settings.c:256,258, fuse/machines/tc2068.c:141`
- Timex TC2068 ROM 1 (EXROM). Also used for TS2068. Embedded in core.

`fuse/128p-0.rom` -required, missing from repo

- System: sinclair-zxspectrum
- Size: 16.0 KB
- Validation: size
- Source: `fuse/settings.c:221,225,229, fuse/machines/pentagon.c:135`
- Pentagon 128K/512K/1024 ROM 0. Required for Pentagon machines.

`fuse/128p-1.rom` -required, missing from repo

- System: sinclair-zxspectrum
- Size: 16.0 KB
- Validation: size
- Source: `fuse/settings.c:222,226,230, fuse/machines/pentagon.c:138`
- Pentagon 128K/512K/1024 ROM 1. Required for Pentagon machines.

`fuse/trdos.rom` -required, missing from repo

- System: sinclair-zxspectrum
- Size: 16.0 KB
- Validation: size
- Source: `fuse/settings.c:223,227,231, fuse/machines/pentagon.c:141`
- TR-DOS ROM (Beta 128 disk interface). Used by Pentagon and Scorpion.

`fuse/gluck.rom` -required, missing from repo

- System: sinclair-zxspectrum
- Size: 16.0 KB
- Validation: size
- Source: `fuse/settings.c:224,228, fuse/machines/pentagon512.c:82`
- Gluck ROM. Required for Pentagon 512K and 1024.

`fuse/256s-0.rom` -required, missing from repo

- System: sinclair-zxspectrum
- Size: 16.0 KB
- Validation: size
- Source: `fuse/settings.c:247, fuse/machines/scorpion.c:76`
- Scorpion 256K ROM 0. Required for Scorpion machine.

`fuse/256s-1.rom` -required, missing from repo

- System: sinclair-zxspectrum
- Size: 16.0 KB
- Validation: size
- Source: `fuse/settings.c:248, fuse/machines/scorpion.c:79`
- Scorpion 256K ROM 1. Required for Scorpion machine.

`fuse/256s-2.rom` -required, missing from repo

- System: sinclair-zxspectrum
- Size: 16.0 KB
- Validation: size
- Source: `fuse/settings.c:249, fuse/machines/scorpion.c:82`
- Scorpion 256K ROM 2. Required for Scorpion machine.

`fuse/256s-3.rom` -required, missing from repo

- System: sinclair-zxspectrum
- Size: 16.0 KB
- Validation: size
- Source: `fuse/settings.c:250, fuse/machines/scorpion.c:85`
- Scorpion 256K ROM 3 (TR-DOS). Required for Scorpion machine.

`fuse/if1-2.rom` -optional, missing from repo

- System: sinclair-zxspectrum
- Size: 8.0 KB
- Validation: size
- Source: `fuse/settings.c:216, fuse/peripherals/if1.c:403`
- Interface 1 ROM (edition 2). Loaded by peripherals/if1.c:403.

`fuse/disciple.rom` -optional, missing from repo

- System: sinclair-zxspectrum
- Size: 8.0 KB
- SHA1: `9a75ed4b293f968985be4c9aa893cd88276d1ced`
- MD5: `78e61a2a02121873c1756b21fd1398b1`
- Validation: size
- Source: `fuse/settings.c:215, fuse/peripherals/disk/disciple.c:279`
- DISCiPLE disk interface ROM. Bundled in repo but not in mem_entries[].

`fuse/plusd.rom` -optional, missing from repo

- System: sinclair-zxspectrum
- Size: 8.0 KB
- SHA1: `6b841dc5797ef7eb219ad455cd1e434ca3b9d30d`
- MD5: `42e5de16fb5e50082bb954ec7ce45851`
- Validation: size
- Source: `fuse/settings.c:246, fuse/peripherals/disk/plusd.c:239`
- +D disk interface ROM. Bundled in repo but not in mem_entries[].

`fuse/didaktik80.rom` -optional, missing from repo

- System: sinclair-zxspectrum
- Size: 14.0 KB
- Validation: size
- Source: `fuse/settings.c:214, fuse/peripherals/disk/didaktik.c:236`
- Didaktik 80 disk interface ROM. Not embedded.

`fuse/opus.rom` -optional, missing from repo

- System: sinclair-zxspectrum
- Size: 8.0 KB
- Validation: size
- Source: `fuse/settings.c:220, fuse/peripherals/disk/opus.c:210`
- Opus Discovery disk interface ROM. Not embedded.

`fuse/mf1.rom` -optional, missing from repo

- System: sinclair-zxspectrum
- Size: 8.0 KB
- Validation: size
- Source: `fuse/settings.c:217, fuse/peripherals/multiface.c:224`
- Multiface 1 ROM. Not embedded.

`fuse/mf128.rom` -optional, missing from repo

- System: sinclair-zxspectrum
- Size: 8.0 KB
- Validation: size
- Source: `fuse/settings.c:218, fuse/peripherals/multiface.c:225`
- Multiface 128 ROM. Not embedded.

`fuse/mf3.rom` -optional, missing from repo

- System: sinclair-zxspectrum
- Size: 8.0 KB
- Validation: size
- Source: `fuse/settings.c:219, fuse/peripherals/multiface.c:226`
- Multiface 3 ROM. Not embedded.

`fuse/speccyboot-1.4.rom` -optional, missing from repo

- System: sinclair-zxspectrum
- Size: 8.0 KB
- SHA1: `16af6f052b38a027dd49ba6e96e3a59d16b62672`
- MD5: `c54aa8f374b0971f51546c29d5d1eba1`
- Validation: size
- Source: `fuse/settings.c:253, fuse/peripherals/speccyboot.c:148`
- SpeccyBoot ethernet ROM. Bundled in repo but not in mem_entries[].

`fuse/ttx2000s.rom` -optional, missing from repo

- System: sinclair-zxspectrum
- Size: 8.0 KB
- Validation: size
- Source: `fuse/settings.c:259, fuse/peripherals/ttx2000s.c:198`
- TTX2000S teletext adapter ROM. Not embedded.

`fuse/usource.rom` -optional, missing from repo

- System: sinclair-zxspectrum
- Size: 8.0 KB
- Validation: size
- Source: `fuse/settings.c:260, fuse/peripherals/usource.c:129`
- Currah uSource ROM. Not embedded.

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