* In the instruction EX DE,HL, HL will not be replaced with IX or IY. The EXX instruction is not affected either.
* If (HL) and L or H are used in the same instruction, L and H are not replaced with IXL or IXH. For instance LD L,(IX+d) stores the content of (IX+d) into L, not IXL.
* DD, '''ED''' or FD prefixes cancel the effects of immediately preceding DD or FD prefixes (they those become NONI: No Op No Interrupt). In other words, ED-prefixed opcodes cannot be altered by DD or FD prefixes.
=== DDCB or FDCB-prefixed opcodes ===