Gamer's Cartridge use its own format for handling save files. It's basically an "one save per file" ( = not compatible with Yabause) and whole save contents structure + extra infos in the header of the file ( = not compatible with SSF).
Main reason of this format is that is makes possible to manually backup a particular save data just by copying a file, and also because if allows recovery of deleted saves : when deleting (or overwriting) a save, it is just flagged as no longer existing, but file itself is kept for a little while.
Format is open source (*) so that -if someone wants it enough, - emulator developers shall be able to add support in the future.
On cartridge side, it is possible to import from any known save data format, and it is also possible to dump save data too. Both features however requires user input on each time, so may not fit your needs.
And the save data dump feature currently only supports output to SSF format, but I shall add support for Yabause format until next release of Pseudo Saturn Kai
🙂
(*) Available in
Pseudo Saturn Kai archive -> SatCom_src_<YYYYMMDD>.7z -> SatCom_src_<YYYYMMDD> -> pseudosat_kai -> vmem -> dev_cart.h -> vmem_bup_header_t structure.