The instruction set of the R800 is almost identical to the Z80. Only 2 instructions have been added: MULUB and MULUW. And many of the undocumented instructions of the Z80 were made official.
[[Zilog]] itself offers the [[eZ80]] processor, a binary-compatible upgrade of the Z80, which runs at up to 50MHz but performs like a 150MHz Z80 due to being three 3 times faster at the same clock speed.
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