SSF - RetroBIOS¶
Technical notes
Sega Saturn and ST-V emulator by Shima, closed source and distributed as a binary. Two artifacts are read here and they describe the same emulator: the Windows build SSF_PreviewVer_R38.zip of 2026-01-01, sha256 7325a9b9d666560ddf632f747fb42ab880f82c45391e51fe0716beb1c535f00b, whose emulator is the 64-bit SSF.exe and which is cited by virtual address; and the Android build SSF_AndroidVer.zip of 2022-08-07, package com.xrea.g2.aaaaaaaa.ssf, whose lib/arm64-v8a/libnative-lib.so keeps its 40738 dynamic symbols and which is cited by symbol. Prose references name the Japanese documentation shipped in Document/.
Every path below is stored in full in SSF.ini and picked through a file dialog filtered on "all files (.)". SSF fixes no filename and no directory for any of them and looks for none, so the names used here are the dumps that fill each slot rather than names the code searches.
Saturn BIOS, [Peripheral] SaturnBIOS. Readme.txt describes the image as the console address range 00000000-0007FFFF and states that the filename is free. Neither a length nor a hash is compared against the file. The one routine that walks the 512 KiB BIOS area is CStateSaveBase::_GetBIOSHash, which folds it into the checksum pair that tags a save state.
Running without it is a supported mode, [Program4] NoBIOS. SSF carries a boot ROM of its own, an embedded program with the SYS_* system calls and the interrupt vectors, and in that mode the backup library is always hooked. Readme.txt records lower compatibility and advises supplying a BIOS.
ST-V is entered by holding left Shift at launch. [Peripheral] STVBIOS names the motherboard EPROM, and both the option reference and the No BIOS entry of Readme.txt state that ST-V does not run without it.
ST-V cartridges are the game and are read from a ZIP: the loader takes the extension of each member as its IC number, accepts 1 through 13, byte-swaps every mask ROM in 16-bit units, doubles each byte of the IC13 EPROM across the 16-bit bus, then mirrors each chip over its window. IC7 and IC13 are exclusive. STV_ROM.html gives the same layout and notes that MAME ROM sets fit once the extensions are changed.
Cheat scripts live in Cheat/ under the disc product number. Six ship with the emulator and the memory cheat dialog writes more.
Everything else the binary opens it also writes: SSF.ini, Setting.ini, Setting/, Backup/, StateSave/, CDIndex/, Snapshot/, Wave/, ExtractSound/, DebugData/, and the LLVM/ object cache that the bundled CreateObject.exe and clang.exe compile from the user's own disc for the local CPU.
4 files | 1 required, 3 optional | 2 in repo, 2 missing | 1 with HLE fallback Categories: 2 BIOS, 2 game data
sega_101.bin optional in repo HLE fallback
Saturn BIOS
- System: sega-saturn
- Size: 512.0 KB
- Aliases:
mpr-17933.bin,sega_100.bin,sega_100a.bin,sega1003.bin,hisaturn.bin,vsaturn.bin - Source:
SSF.exe 0x43d770,SSF.exe 0x129a2f8 with the filter at 0x129a310,SSF.exe 0x43ff96,libnative-lib.so SSF::CStateSaveBase::_GetBIOSHash 0x134b8ec-0x134b924,Document/Readme.txt BIOSファイルについて - Platforms: batocera, emudeck, lakka, recalbox, retroarch, retrobat, retrodeck, retropie, rocknix, romm
- Any dump of the 512 KiB console ROM, the compatible machines included. Area code is chosen by [Peripheral] Areacode and AutoAreacode, not by the image, so no region selects this file.
epr-20091.ic8 required in repo
ST-V BIOS
- System: sega-stv
- Size: 512.0 KB
- Aliases:
epr-23603.ic8,epr-19730.ic8,epr-19854.ic8,epr-17951a.ic8,epr-17952a.ic8,epr-17953a.ic8,epr-17954a.ic8,epr-17740.ic8,epr-17740a.ic8,epr-17741a.ic8,epr-17742a.ic8 - Source:
SSF.exe 0x43d91f,SSF.exe 0x129a328,Document/Readme.txt ST-V BIOS option,Document/Readme.txt No BIOS option - Loose 512 KiB EPROM image, read outside the cartridge ZIP. Any of the board revisions is accepted, the code branching on none of them.
<cartridge>.bin optional missing game_data
cartridge image mapped at A-Bus CS0
- System: sega-saturn
- Source:
SSF.exe 0x43e26b,SSF.exe 0x43e178,SSF.exe 0x129a340,SSF.exe 0x916e5e-0x916e84,Document/Readme.txt Data Cartridge option - [Peripheral] DataCartridge, gated by DataCartridgeEnable and off by default. SSF reads the file at the configured path into the 32 MiB A-Bus CS0 window and identifies it in no way; the dumps that belong there are the two Saturn ROM carts, mpr-18811-mx.ic1 for The King of Fighters '95 and mpr-19367-mx.ic1 for Ultraman. Readme.txt records the option as unverified.
<name>.cht optional missing game_data bundled
cheat script
- Path:
Cheat/<product id>/<name>.cht - System: sega-saturn
- Source:
SSF.exe 0x4403c0,SSF.exe 0x12998a0,SSF.exe 0x129a658,SSF.exe command table 0x128c570-0x128c808 - Read when [Program4] EnableCheat is set, from the directory named after the disc product number. The format is a script language: triggers on first read, field, file, sector, CDDA and scanline, memory reads and writes, storage slots, branches and labels. Six ship with the emulator; the memory cheat dialog saves its own with the target address in the name.
Generated on 2026-08-23T16:12:06Z