> is that really cheaper than porting a calculator os to a modern CPU? There was a whole OS and programming environment in there, very closely tied to the CPU

> is that really cheaper than porting a calculator os to a modern CPU? There was a whole OS and programming environment in there, very closely tied to the CPU architecture. All the calculator's advanced functionality, including graphing, equation editor UI, equation solver, compiler and decompiler, etc., was written in the OS's own stack-based system language. Porting all of that to another CPU family would definitely have been much more work than writing an emulator for the old Saturn CPU. Performance must not have been a problem, thanks to ARM and Moore's law.