This is awesome! I did a similar barebones emulator for x86 ELF binaries but I took a few shortcuts. I shimmed _start in the emulator and just jumped to main. Then I called exit back in the emulator when main returned.

I haven't yet gotten to implementing syscalls but the simple ones (write, exit, etc.) aren't terribly hard once you have the general infrastructure.

https://notes.eatonphil.com/emulating-amd64-starting-with-el...