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CPUs without microcode exist. While microcode isn't exactly a new innovation, early mass-market CPUs were not implemented that way.

• pjmlp 8y ago
  Microcode free CPUs was mostly a RISC thing, and basic CPUs like Z80 and 6502, almost everyone else always had some form of microcode in them.
  • shakna 8y ago
    > CPUs without microcode exist. While microcode isn't exactly a new innovation, early mass-market CPUs were not implemented that way. > Microcode free CPUs was mostly a RISC thing, and basic CPUs like Z80 and 6502 Those quotes aren't incompatible - the 6502 and Z80 are core to the early mass-market computer movement. So whilst microcode-free may be rare now, there was a time when it was the norm.
    • pjmlp 8y ago
      The norm in the context of 8 bit home micros.
• shawnz 8y ago
  Right, but it wouldn't be possible for a modern CPU (for example: how would you retain compatibility with older architectures? how would you patch it if you find a critical bug in an instruction?) Furthermore the parent was asking about having no microcode running on the CPU which is what I was speaking to. A CPU designed to use microcode can't be run without microcode. But yes, it is of course possible to design the CPU to not use microcode in the first place.