Comment by ufo
5 years ago
On the matter of portability, I wonder if it would be possible to use some macro magic and/or a code generator to convert the tail-call version back into a more traditional while/switch loop, for the stack-based architectures.
While the tail call version is more architecture dependent, it's nevertheless more portable than assembly language. It's still C.
I haven't implemented the fallback yet, but my thought was to keep most of the structure the same (dispatch function tail calls to the function for an individual operation) but then have the individual operation just return instead of tail calling back to dispatch.
I think this would be portable while still avoiding some of the performance problems associated with a traditional switch (like the bounds check).
I'm curious how this approach would fair for microcontrollers, well cortex m0-m4's actually. They're arm32 bit and may not have enough useful call registers. Still parsing protobuf's or interpreting WASM faster would result directly in better battery performance, etc.