Main page is http://cowlark.com/cowgol/
It used to support the Apollo Guidance Computer used in the Apollo spacecraft, but I had to remove the code generator while rewriting the compiler and I haven’t reworked the AGC backend.
http://cowlark.com/2019-07-20-cowgol-agc/index.html
The author also ported the Fuzix operating system to the Raspberry π pico.
http://cowlark.com/2021-02-16-fuzix-pi-pico/index.html

His tool https://github.com/davidgiven/narcissus to remap keys might be interesting too.
So is his Forth system http://cowlark.com/fforth/