I think it may be the tube host code that copies the language ROM over the tube to start running on the 2P. Yes, that is part of the OS on MOS 3.50 but for OS 1.20 it is in the DNFS ROM, though not really part of DFS. It may be possible to create a version of the tube host code that implements MOS 3.50 relocation that still runs under MOS 1.20, especially if you're prepared to sacrifice having NFS in the same ROM as DFS....They're assembled to run from $8000, so they work as-is in a sideways bank on the host CPU, but they've got a 6502 parasite address of $b800, so they'll need relocating when copied across (which only MOS 3.50 will do), or the parasite address needs to be ignored (which only MOS 3.50 will do).
Whether it is worth the effort is another question, plus there is complication of ROMs whose relocation tables are not in the ROM concerned. IIRC the tube client has a minimal command environment that can be used to *RUN tube-ready languages so that may be the easier approach.
Statistics: Posted by Coeus — Mon Dec 08, 2025 11:42 am