Changes
Z80
,/* Oddities */
* All CB-prefixed opcodes and half of the standard opcodes (from &40 to &BF) follow a strict uniform layout. The exception is the HALT instruction (opcode &76), which replaces the expected LD (HL),(HL) instruction.
* The rest of the opcode table is also ordered organised quite neatly but in an horizontal way instead of vertical.
* RETI and RETN are identical instructions [https://floooh.github.io/2021/12/17/cycle-stepped-z80.html#the-ei-di-and-retiretn-instructions Source]. The only reason for RETI is so that some other hardware can detect the specific case of returning from the interrupt, by detecting the RETI opcode on the data bus.
* EI has a 1-instruction delay. It is necessary for doing EI/RETI without any danger of nested interrupt routines.
