New RPL firmware for 50G - Revisited

[David Hayden]

(02-19-2014 04:01 PM)Tugdual Wrote:  How do you guys start such a project?

I think the motivation came separately from Claudio and myself. Claudio was wondering what it would take to reimplement the 50g ROMs in native ARM code. Independently, I had started a project to implement system RPL in C++ code. Claudio posted something here and pretty soon Han joined in too.

To me, the first big question was "what level of compatibility?" We decided on userRPL at the source code level. In other words, if you type in a userRPL program, we hope that it will run in newRPL. On the other hand, a userRPL program in binary form won't run (although it may be possible to convert it automatically). SystemRPL programs definitely won't work. Saturn assembly is out and most ARM assembly will need to change since we aren't following the binary interface.

The up side of limited compatibility is that we can take advantage of modern hardware. The MMU will make memory management easier. Objects are all 32-bit aligned to increase access speed. I think the coolest thing is that Claudio came up with a framework to allow adding user-defined types in a meaningful way.

Han and Claudio, please correct anything that I have misstated.

Dave