I'm using Rust to write code for an embedded target of mine -- a CPU made on a digital circuit simulator, implementing a subset of Thumb (specifically, thumbv6m-none-eabi). The CPU is slow (~40kHz) so every wasted instruction adds up to a noticeable slowing down of stuff I run. I understand this is nowhere near anything Rust was designed to run on. There is something I'm blocking on: all functions, even leaves, have a frame pointer, which I don't need. For example, here's a small function tha...
