openfirmware VS swapforth

>I find, only pointfree notation has some beauty to it that makes reading code sweet again.

I haven't written FORTH code in ages, but I still enjoy reading well written FORTH code for its pure literary pleasure!

https://github.com/MitchBradley/openfirmware/blob/master/for...

As a SPARC and PowerPC guy, of course I wish the foundation would settle on IEEE-1275 (a.k.a. OpenFirmware) as the default firmware/bootloader, but I'm not holding my breath. Full implementation available, it just needs the Forth interpreter ported to RISC-V and maybe some additional drivers.

Thanks! Found the port of this to the board I want :) https://github.com/jamesbowman/swapforth/tree/master/j1a

It's a standard thing to do in EE curricula; you normally do it in a one-semester class, and there are literally thousands of open-source synthesizable CPU cores on GitHub now.

To take two examples to show that designing a CPU is less work than writing a novel:

- Chuck Thacker's "A Tiny Computer", fairly similar to the Nova, is a page and a half of synthesizable Verilog; it runs at 66 MHz in 200 LUTs of a Virtex-5: https://www.cl.cam.ac.uk/~swm11/examples/bluespec/Tiny3/Thac...

- James Bowman's J1A is more like Chuck Moore's MuP21 and is about three pages of synthesizable Verilog: https://github.com/jamesbowman/swapforth/blob/master/j1a/ver... and https://github.com/jamesbowman/swapforth/blob/master/j1a/ver.... You can build it with Claire Wolf's iCEStorm (yosys, etc.) and run it on any but Lattice's tiniest FPGAs; it takes up 1162 4-input LUTs.

I haven't quite done it myself. Last time I played https://nandgame.com/ it took me a couple of hours to play through the hardware design levels. But that's not really "design" in the sense of defining the instruction set (which is also kind of Nova-like), thinking through state machine design, and trying different pipeline depths; you're mostly just doing the kind of logic minimization exercises you'd normally delegate to yosys.

In https://github.com/kragen/calculusvaporis I designed a CPU instruction set, wrote a simulator for it, wrote and tested some simple programs, designed a CPU at the RTL level, and sketched out gate-level logic designs to get an estimate of how big it would be. But I haven't simulated the RTL to verify it, written it down in an HDL, or breadboarded the circuit, so I'm reluctant to say that this qualifies as "designing a single CPU" either.

Also worth checking is the Swapforth Github repository.