I have just released the source to a HP48GX emulator for the iPhone and iPod Touch.
It’s a very rough port of x48 to the iPhone, but it works :) There is the occasional screen glitch and I’m not too happy with the screen buffer code. Something else that is a bit annoying is that it appears that compiling in Debug mode to run on the device does not work. It looks like one of the case statements in the x48 emulation code is too big to be compiled for ARM under gcc. I had a quick look at using the LLVM compiler but it didn’t seem to like it.
The code can be downloaded from http://github.com/dparnell/i48/tree/master