neat project for the HP48

Has anyone thought about rewriting the HP48 ROM? If Raymond is reading this -- perhaps incorporate Speed UI into a custom ROM. It has been a while since I worked on HP48 hardware (and software), but I imagine it would not require too much work given the right tools (sadhp to decompile the old ROM and then make adjustments to "update" to a custom ROM). We could even borrow ideas from the HP49/50 series (e.g. flash pointers).

I have designed PCBs for single-chip 512KB memory upgrades (128KB Port 0, 128KB Port 1, and 256KB Port 2), and could work on putting together a mini-daughter board with a switch to swap between built-in ROM and the new ROM.


Hi Han,

if you update the display to a higher resolution screen, then I am in.

I know that this would require rewriting the display handling code.

I believe - no, I know - that what you are proposing could be done
much easier with the 49G architecture (giving it a 48 housing ;-).




You have mail:-)


I've been toying with the idea of creating an 32-bit, byte-addressed RPL system and then trying to port something like the HP-48G to it. This would be a big project because of both changes. The size of all objects would change and they'd be expressed in bytes instead of nibbles. My fantasy would be get the 48G code running with 32-bit RPL running natively on the 50g hardware.

All that stands in my way in the dozen or two full-time RPL and assembly developers who'd be needed to make this happen.... :)



I have always wanted to one day have the time to convert the HP50G from running emulated Saturn code to running pure ARM code. I imagine I would run into problems with the Kinpo OS.

But for the HP48, the ROM is relatively smaller (even more so for the HP42S). I am currently trying to write my own HP42 emulator for the HP48/HP50 (yes, I know Hrastprogrammer has an excellent one, but I'm more in it for the learning experience).


if you update the display to a higher resolution screen, then I am in.

Count me in on that one.

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