Porting the NumWorks firmware to the HP Prime

[Jean-Baptiste Boric]

The HP Prime has 256 MiB of Flash. While I develop with a GDB stub that can (slowly) load ELF images as big as the RAM through the UART, replacing PRIME_OS.ROM is currently the only option for others and it's only 1 MiB to work with.

I've mapped most of the obvious keys combinations I could to their closest epsilon internal event equivalent. I could map more of them to concepts epsilon knows about like shift-home switching to the Settings app with more intrusive changes to the code, but I stick to a vanilla port for now. However, the HP Prime and the NumWorks have wildly different UI, featuresets and software philosophies. The keyboards are reasonably close enough that it mostly works out in practice (the TI-83 Premium CE would've been a nightmare to map), but it'll never be perfect: what should I map the CAS key to for example?

As for popularity, it's hard to tell how popular in relative and absolute terms the HP Prime really is. It probably varies quite a bit by country. Also, there's not only the physical item to consider, but also the various mobile apps and paid versions.

What is obvious is that the HP Prime platform overall is at the very least not an outright commercial failure otherwise HP would've pulled the plug a long time ago. Beyond that, I don't have any data points to speculate/extrapolate so I won't try to. But sellers that don't sell lots of HP Prime will not stock a lot of them in advance and they will tend to run out of units until they get to restock (possibly waiting on a production batch to complete and ship too) on a semi-regular basis, so I wouldn't worry too much about that as long as it's not a global shortage.