The sBPF Programming Book

Seven tiny sBPF programs that turn slippage, deadlines, rent floors, and fee ceilings into hard atomic preconditions on any transaction, written in pure assembly and live on devnet and mainnet at the same program IDs.

Anchor and Pinocchio are good defaults until you are writing a 7-CU program. At that point the framework is most of the binary. Notes from rewriting the Shield guards out of Rust and into raw .s files.