MMBasic is the actual basic used on the CMM2. It is really a great system with some advanced features for BASIC. https://www.mmbasic.com/downloads.html

I do recall that there is a port of MMBasic for the Raspberry Pi floating around somewhere. I think it is on the forums at https://thebackshed.com but I couldn't tell you how to find it. I do think it runs under Linux and not on bare metal but I might be mis-remembering.

Actually dug through because I only had a vague recollection. So the Pi-Cromite version I remembered has been discontinued. However, there is a MMBasic for Linux that cribs some code from that project. And, it can be compiled for the Raspberry Pi. I might venture to suggest that this might be one of the most fully featured Basic implementations that can found for the Raspberry Pi. Link here: https://github.com/thwill1000/MMB4L