Why I'm Building a Game Boy Emulator (in Python, from Scratch) A few months ago I asked myself: do I actually understand how a CPU works, or do I just think I do? I've been writing software for years. I know what a CPU is, roughly. I've heard the words: registers, opcodes, clock cycles. But if you asked me to explain exactly what happens between the moment a program starts and the first pixel appearing on screen, I'd be hand-waving pretty fast. So I decided to stop hand-waving. Why a Game Boy I wanted something real to dig into. Not a toy CPU invented for a textbook, but an actual piece of hardware with real constraints, real quirks, and real games running on it. The Game Boy fit. It's a complete computer (CPU, display, audio, input, memory) squeezed into something that runs on two AA batteries. Simple enough that one person can understand the whole thing. Complex enough that it's actually interesting. It also has extraordinary documentation.…