Zx-81 released a port of X48, a unix emulator for the HP48 Calculator. Release notes:

X48 is an unix emulator (under X Window) of the famous HP48 GX calculator. It has been written many years ago by Eddie C. Dost in C langage.
I’ve sucessfully modified and port the source code of the 0.4.0 version using PSPSDK environment. It’s now working fine on PSP !