#1 Non-standard opcodes should be optional

[Anonymous]

Non-standard and undocumented opcodes should be
optional; i.e. "standard" Z-80 has only one NEG
instruction (opcode ED 44), and it does not know
anything about IXh, IXl, IYh, IYl registers, nor
"strange" instructions such as "LD B,RLC (IX+d)".
I know, these opcodes may be functional in many Z-80
devices, but I think it's not good to have those extra
opcodes supported in some particular cases.