Changes
Z80
,/* Chip Variants */
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]
Fun fact: Way more GBZ80 cores were produced for Gameboy hardware (118 million Gameboys and 81 million GBA) than all the Z80 chips produced for home computers and game consoles.[https://www.chibiakumas.com/z80/Gameboy.php Learn GBZ80 Assembly Programming with ChibiAkumas]
The Sega Mega Drive, Master System and Game Gear use a standard Z80 CPU. [https://drive.google.com/file/d/1v7H1rwjmYNSpvxWAp74wVIU15RyR0Dry/ Genesis sound software manual] [https://segaretro.org/images/d/d6/SoftwareReferenceManualForSegaMarkIIIEU.pdf Master System reference manual] [https://segaretro.org/images/1/16/Sega_Game_Gear_Hardware_Reference_Manual.pdf Game Gear reference manual]
