the WD Pascal microengine. Why was it done? In the
late 70s Pascal was
emerging as a teaching language and it was highly standardized. Most
small systems had the resources to run it as native compiled but the
authors (UCSD) decided that portable Pcode would allow more platforms
to run it as the Pengine was easier to code than a whole compiler.
Not only that, but the P-code was often more compact than the equivalent
native machine code. (It's probably even more compact than modern
RISCy processor code.) Compactness of code is an enormous advantage in
a limited memory-space environment.
Tim.