In addition to the Interim Lisp system I mentioned in another comment, there are a number of bare-metal applications for the Raspberry on github (mostly ports o

In addition to the Interim Lisp system I mentioned in another comment, there are a number of bare-metal applications for the Raspberry on github (mostly ports of games). I especially like this Commodore 64 emulator (also based on circle): https://github.com/randyrossi/bmc64 https://github.com/randyrossi/bmc64