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Comment by jstanley | Hacker News Reader

Thanks, this is serendipitous timing. I definitely plan to watch the YouTube playlist.

I'm designing a simple CPU at the moment[1] and one of the things that keeps me awake at night is thinking about how to make a compiler for it.

It only supports 64K words of RAM (and I'm not planning to implement bank switching), and I definitely want the compiler to be self-hosting on my CPU, so retargeting LLVM or similar won't be applicable.

I've looked at Small-C[2], Cowgol[3], and PL/0[4] which all target related goals, from different directions.

[1] https://github.com/jes/scamp-cpu

[2] https://en.wikipedia.org/wiki/Small-C

[3] http://cowlark.com/cowgol/

[4] https://en.wikipedia.org/wiki/PL/0

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Consider Forth. The simplicity of the language's syntax means that a compiler is basically just a table lookup, and they can fit into just a few kilobytes of code.

Even if you don't port or implement an actual Forth, a Forth-like threaded code model fits tiny memory constraints very well, with very high code density and only moderate overhead. If you add a couple registers to the VM for easing pointer access, it becomes a suitable target for C-like languages, too.

Have you taken a look at Ferret ? https://ferret-lang.org/ ?

Ferret is a free software lisp implementation designed to be used in real time embedded control systems. Ferret lisp compiles down to self contained C++11. Generated code is portable between any Operating System and/or Microcontroller that supports a C++11 compliant compiler. It has been verified to run on architectures ranging from embedded systems with as little as 2KB of RAM to general purpose computers running Linux/Mac OS X/Windows.

I hadn't seen it, and it looks cool, thanks.

I'm really keen to be able to run the compiler end-to-end on the CPU itself, so I think getting C++11 working would be the stumbling block there.

Maybe this is interesting to you as well? https://github.com/cksystemsteaching/selfie

I'm looking at this one for a CPU design I've been working on. :)

https://github.com/jserv/shecc They just released it!

Consider the KenCC[1][2] - somewhat minimalistic, and the flavor of C it uses is very sane.

[1] http://gsoc.cat-v.org/projects/kencc/

[2] yes, by that Ken

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