A new RPL firmware for the 50g

[Claudio L.]

(01-01-2014 04:32 PM)David Hayden Wrote:  There are two advantages to supporting SysRPL. First, if we write some of the code in SysRPL then it will be MUCH smaller than equivalent C/C++ code. This will matter if we want to put it on hardware.

In my experience with hpgcc3, this doesn't necessarily hold true (at least the MUCH smaller part). Once you have the base code, the rest becomes mostly function calls into the ROM, much like sysRPL, and with most of the functions taking arguments directly from the data stack, a BL instruction in ARM assembler is all it's needed, so 4 bytes, same as an RPL pointer, really.
The examples I worked on, they all ended up very competitive with sysRPL code. ARM code can be surprisingly dense. I know it sounds counterintuitive, I was surprised by the results.

(01-01-2014 04:32 PM)David Hayden Wrote:  Second, it means that a translator from existing HP libraries to "new RPL" is possible and that would be a big help in porting existing SysRPL to the new system.

Keep in mind also that, even if we don't implement the SysRPL entries, we'll still have to write all/most of the functionality in them.

Yes, this would be a really good thing. The big question is if it can ever work well enough to be useful. If we can only run 5% of the code in hpcalc.org then the whole effort becomes a moot point. And to be able to run 95% of the code in hpcalc.org, we'd have to have all 7000+ entries in perfect working order (and I mean "perfect"), which would probably tie us to a design that has already been maxed out by the 50g.

(01-01-2014 04:32 PM)David Hayden Wrote:  Claudio, I'm honored that you're following my progress. I'm certainly willing to collaborate on a system, but I'm thinking that it's too early to make it available. If I get bogged down in discussions and disagreements I might lose my enthusiasm. You've been through the process with HPGCC so I'm curious to hear your thoughts.

With HPGCC, there were very few disagreements and hardly ever arguments, since technical discussions usually have reasonable solutions that everyone agrees on (after all, we are all following the scientific method, aren't we?). We only faced 2 major roadblocks: a) lack of interest from the community (one thing is people cheering on a forum, a very different thing is people actually coding and helping the project), so we were basically on our own, being the main developers and practically the only users too (count how many programs in hpcalc.org use HPGCC and you'll see what I mean). And b) time. Time makes people graduate, get married, switch jobs and move on in life. If the project takes too long to complete, then it's likely to end up forgotten.
That's why either we get a few hands together and advance the project quickly, or the project is already dead.