HP 48GX Collector’s Edition (merged) - please don't start two threads

[Eric Rechlin]

(11-26-2023 11:18 PM)c3d Wrote:  1) a fully-compatible HP48 clone, using e.g. Saturn emulation and HP ROMs, much like iOS or Android apps?

2) a source-compatible firmware that is simply in the spirit of the HP48, but takes full advantage of today's hardware, even if that means being unable to run anything that relies on SYSEVAL or Saturn assembly language?

To me, option 1 only makes sense if it is on a device with the exact same keyboard layout as the 48, because trying to achieve that with fewer keys or a substantially different layout would not work very well. But then you'd suffer from what the 50g suffered from -- a dead-end platform with no real way to fix bugs or add functionality, along with being cursed with the inefficiencies of emulation.

Option 2 seems like a much better idea because it would allow for more flexibility (like support for higher-resolution screens and adding functionality), while also performing better and having a long-term future.

Given enough system resources, however, binary compatibility could be achieved by having a lookup table to translate User RPL entry points (and even System RPL, provided enough development time to handle supported entries) at runtime, if the new firmware has all commands implemented with compatible behavior. A built-in Saturn emulator could even provide binary compatibility for assembly programs, but that seems even less likely.

Option 2 is really the Free42 to Plus42 approach. First re-create everything to provide full backwards compatibility with the original calculator. Then extend it to add functionality we could never have before. The 50g AUR appendix I lists all the User RPL commands in the 50g along with which RPL model they first appeared in. I believe this is an almost complete superset of the 48SX and 48GX lists, so one possible development path would be to first get the calculator to SX-level functionality, then GX-level, and finally 50g-level and beyond.

Of course that is all just a dream because I can't see anyone having enough time to develop the above, but it would allow for my dream machine -- a platform for future RPL devices, which could behave in "48SX" or "48GX" or "50g" modes for running programs from each, perhaps with two different sets of physical hardware for the two different key layouts, or a third layout to combine the best of both. For example, starting with the 50g layout but making Row 4 have 6 keys would allow for ENTER to be moved to a double-wide position on row 6, and additionally making Row 5 have 6 keys would allow for a net increase of 1 key so that Z and ÷ wouldn't have to share a key, which would totally break backwards compatibility but would resolve my second biggest gripe about the 49/50 layout. Put all that in a stretched DM32 device and you'd have the perfect calculator.