chip8-sharp

chip8-sharp is a complete CHIP-8 emulator written in C#. CHIP-8 is small - a few dozen instructions, simple memory, a 64 by 32 pixel screen - and that is exactly why it is the classic "first emulator". But the difference between a toy and a project lies in that word "complete": the full instruction set, timers and input, not the half that is "enough for one game".

The core is a pure library with no rendering dependency, exactly like the Game Boy one. That is what lets the whole machine run headless and go through test ROMs without any window, turning "probably works" into "verified".

CHIP-8 is a rite of passage for anyone who wants to understand how emulation works. It is small enough to hold whole in your head, and real enough to teach everything larger emulators do on a bigger scale: the fetch-decode-execute cycle, memory, timers, input handling.

Its size is an advantage, not a limitation. It is precisely because it is small that you can do it genuinely correctly, not just "almost". Every opcode can be checked on its own, and the community has ready-made ROMs that print "OK" or "FAIL" for each instruction.

The whole machine turns around one loop. An opcode is two bytes, and individual bits say which instruction it is and which registers it should act on. Decoding means cutting the right fragments out of those two bytes and routing them to the right branch.

The whole charm of CHIP-8 is that decoding can be broken down into its parts. A sixteen-bit opcode splits into fragments with fixed meaning, and once that anatomy is understood it turns the whole instruction list into a few simple rules.

What comes out is a small but polished emulator - the full instruction set, timers and input, verified headless against community ROMs. The same trick as with the Game Boy, separating logic from display, means correctness is proven, not declared. It is a project small by design but genuinely finished, not abandoned at "enough for one game".