There was a very old post...
"Benny:
Hi @all
After 2 Weeks of playing with the RKP-Game-Disassembler i had now
enough information to made my first RKP-Assembler (BETA-Version).
Includes a Documentation and a sample-program (Data-Viewer) and
some RKP-Game-Files. Actually it's all Assembler (LSI ZSP400 Instructions).
File-Upload.net - RKP-Disassembler_and_Assembler_v01.zip
Enjoy
Regards
Benny"
The link is still working.
P.S. Hot tip for searching via Google:
use "filetype:torrent", "filetype:rar", etc. before the words
to search for the pages with the links to those files