A new RPL firmware for the 50g

[Han]

I really don't see the point of re-implementing SysRPL. The whole point of SysRPL was that it served as an intermediate layer between assembly code and UserRPL in order to not have to code every individual command in assembly. However, if you're going to use C (as an example) to create commands that will replace the UserRPL ones, then there is no point in preserving the underlying SysRPL layer. Instead, you would have hooks for C code in its place. This will mean a lot of SysRPL code will no longer be compatible. However, I think the tradeoff is for the better -- SysRPL code for much more legible C code.

What is still needed is some common library code as I am sure that many of the UserRPL commands will have overlapping code. For example, one method for solving a linear system involves Kramer's Rule, which uses determinants. The best way to see what sort of core math library is necessary would be to decompile the existing ROM. If anything, this would actually be more useful in general. A community-driven disassembly of the current ROM with comments could not only preserve the algorithms but also enable you to readily implement the same algorithms in whatever language you prefer. It also opens up paths to better algorithms since more people will have their eyes on the code. Such code could serve to teach those interested in calculator development about the link between software and hardware. And lastly, long-standing bugs can finally be fixed for those who want to remain as close to the "official" firmware as possible.

Another route would be to simply import existing (free) libraries and build from scratch (much more difficult and time consuming).

As for HP releasing the source -- I have raised this question myself many times, and the answer has always been no. Not even for the HP48 series, because its source is the base for the HP50G, which is still being sold.

Just out of sheer curiosity -- are there a lot of folks who know ARM assembly programming?