CHIP-8 in Common Lisp: Disassembly

In the previous posts we looked at how to emulate a CHIP-8 CPU with Common Lisp. After adding a screen, input, and sound the core of the emulator is essentially complete.
I’ve been guiding you through the code step by step and it might look simple, but that’s only because I went down all the dead ends myself first. In practice, when you’re writing an emulator for a system you’ll need a way to debug the execution of code.