Changes
Z80
,/* DD or FD-prefixed opcodes */
When a DD or FD prefix is followed by a CB byte, the CB acts as a second prefix. A mandatory displacement byte comes next, and then the actual opcode. If the instruction produces output other than in the flags (i.e. all except BIT), then the result gets placed both into (IX+d) or (IY+d) and the register one would normally expect to be altered.
DDCB and FDCB-prefixed instructions only increment the R register twice. This has been confirmed on [https://stackoverflow.com/questions/8540518/z80-memory-refresh-register#comment25506533_16222002 Stack Overflow]
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