According to David Given (hjalfi), R.T.Russell's implementation of BBC-BASIC for the Z80 CPU is now open source, with the zlib license, read more here:
http://cowlark.com/2019-06-14-bbcbasic-opensource/index.html
David also provided the source in his "cpmish" repository on github:
https://github.com/davidgiven/cpmish/tree/master/third_party/bbcbasic
And btw, David has nice youtube videos, like a 9 hours long one coding vi clone for CP/M, quite an adventure/fun to watch, trust me :)
This repository contains my own modifications, initially mostly clean-ups, usable Makefile, better integration of needed tools, and so on. Later, I plan other more important changes as well, not only these 'cosmetic' ones.
This has been massaged lightly by me, dtrg, to assemble with zmac. The main issue is that zmac has different keyword rules to the assembler it was originally written in, and doesn't allow labels like OR and AND. It also ignores $ in labels, so PUSH and PUSH$ are considered the same. I've renamed these. I've also removed the checksum verification code, as I don't have the tool to generate the checksum and it's not really needed. Very little else needed work.
The original source provided to me by R.T.Russell is available in the VCS.
David Given [email protected]