Depends. Some CPUs were just ISA-compatible independent designs, such as the K1801VM1 popular in home computers, which used PDP-11 ISA; there never were any sin

Depends. Some CPUs were just ISA-compatible independent designs, such as the K1801VM1 popular in home computers, which used PDP-11 ISA; there never were any single-chip designs using that ISA to copy from. Some CPUs were clones modified to fit weaker domestic manufacturing capabilities, like KR580VM80A which had a revised design of the i8080. Some CPUs were almost literal reverse-engineered clones, including the copied microcode, for example K1810VM86 (8086).