Me running through Performance-Aware Programming in Rust. There are certainly bugs in the 8086 simulator code; I mostly just bashed it out without thinking very hard, and without testing it except by using Casey's provided tests. It does, however, conform to all Casey's provided test cases except the "completionist decode" one.
The code in this repo is MIT-licensed.
However, note that the included submodule is licensed very restrictively, and you might not even be permitted to clone it.