Changes
Z80
,/* 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)]
* The Nintendo documentation doesn't mention M-cycles or T-states at all. They only mention CPU cycles, which are the equivalent of NOPs in the CPC world. Also, the GBZ80 has different timings than the Z80. For example, CALL nn takes 6 cycles for on the GBZ80, but only 5 NOPs for on the Z80. [https://archive.org/details/GameBoyProgManVer1.1/ Gameboy programming manual]
* 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), the 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 of WZ and Q internal registers). [https://www.pastraiser.com/cpu/gameboy/gameboy_opcodes.html GBZ80 opcodes]
