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Your comment got me interested and i compared die photos of both chips. Intel 8080A die photo: https://vintageteardown.com/wp-content/uploads/2018/04/Intel8080

Your comment got me interested and i compared die photos of both chips. Intel 8080A die photo: https://vintageteardown.com/wp-content/uploads/2018/04/Intel8080A_10x-1.jpg https://vintageteardown.com/wp-content/uploads/2018/04/Intel... 580BM80A die photo: https://raw.githubusercontent.com/1801BM1/vm80a/master/img/vm80a.jpg https://raw.githubusercontent.com/1801BM1/vm80a/master/img/v... I am not an expert in CPU design, so please correct me if i am wrong, but chips look rather different (at least Intel logo was removed on the 580BM80A die). Could it be that 580BM80A implements Intel's ISA, but actual CPU architecture is of their own? And could we call it a "copy"/"replica" if so? Like could we say that AMD CPUs are replicas of Intel CPUs, because they implement the same ISA?

kens 6y ago
Those two chips are a lot more different than I'd expect. (Even taking into account the 90 degree rotation.) In particular, the ALU (upper-left in Intel photo) is fairly regular, while the ALU in the Russian photo (lower-left) looks like random logic. And the PLAs and instruction register seem entirely different between the two. I was skeptical at first, but I think it's possible that the Russian chip is a different implementation, and not just the same circuitry with the layout re-done for their process. It would require a closer look at the circuitry to determine for sure. For the first link, removing https will avoid the expired certificate warning: http://vintageteardown.com/wp-content/uploads/2018/04/Intel8080A_10x-1.jpg http://vintageteardown.com/wp-content/uploads/2018/04/Intel8...