| R (Memory Refresh) || 8-bit || Increments after each instruction fetch to refresh DRAM || Only the lower 7 bits are incremented
|}
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== Internal state ==
| IMP (Indexing Mode Prefix) || 2-bit || Specifies the indexing mode (DD for IX+d, FD for IY+d, or none for HL) || Indicates use of index registers (IX or IY) for memory access
|}
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== Opcodes ==