== Chip Variants ==
The [[GBZ80]] (Sharp SM83) that powers the original [[Nintendo GameBoy]] is an in-between the [[Intel 8080]] and Z80. [https://gbdev.io/resources.html Awesome Gameboy resources] [https://emudev.de/ Emudev (q00.gb-si)]
The GBZ80 lacks the alternate register set, the dedicated I/O bus, the NMI pin, the IM instructions, the I and R registers, the index registers (DD and FD prefixed opcodes are missing), ED prefixed opcodes (including block transfer), the sign and parity/overflow flags (and all conditional instructions that used them), the undocumented flags (thus no leaking WZ register). [https://www.pastraiser.com/cpu/gameboy/gameboy_opcodes.html GBZ80 opcodes]