[logicalshift]

RISC OS is still available for the Raspberry Pi. You get to basic by pressing F12 and typing ‘BASIC’, and it has a built-in ARM assembler already - the manuals are all available online, there’s a BASIC manual and the Programmers Reference Manual for the whole OS.

(It’s exactly like a BBC B because this is the same version of BASIC, ported to ARM, it even emulates some of the hardware because back in the day they wanted to make software run without porting)

In theory typing ‘*CONFIGURE LANGUAGE 20’ (BASIC being module 20) should make it into a machine that boots straight to BASIC but when I tried it just now it just ignores the setting because the keyboard drivers aren’t loaded soon enough.