P2 Loader Specs?

Dave Hein

Is there a post or document that describes the loading protocol for the P2? I would like to write a stand-alone loader that I can execute from the command line. I know things will change once the loader is put in ROM, but I'd like to be able to load binaries to the FPGA emulation now instead of waiting for the ROM. Does the current FPGA image use a similar loading protocol that is used with the P1?

David Betz

I think it's pretty much the same as it was with the old P2 and that protocol is implemented by my p2load program.

https://github.com/dbetz/p2load

I was going to do this myself but I got bogged down with a loader I'm writing for Jeff Martin for the ActivityBoard WX. That's done now so maybe I'll take a crack at updating p2load if you don't beat me to it! :-)

Dave Hein

I played around with p2loader a bit, and I got it to build under cygwin. However, there's no response after the loader image is loaded. I realized that loader.spin needs to be rewritten for the latest version of the P2. I did try replacing it with a test program, but I didn't get any output from it.

David Betz

Dave Hein wrote: »

I played around with p2loader a bit, and I got it to build under cygwin. However, there's no response after the loader image is loaded. I realized that loader.spin needs to be rewritten for the latest version of the P2. I did try replacing it with a test program, but I didn't get any output from it.

Not surprising. Chip said that the new P2 loader protocol was "pretty similar" to the old P2, not exactly the same. I'm waiting to see if he'll provide more details about any differences. As you say, the second-stage loader has to be rewritten for the new P2 instruction set.