- The Zilog Z80 is an 8-bit microprocessor designed by Zilog that played an important role in the evolution of early computing. Launched in 1976 and software-compatible with the Intel 8080, it offered a compelling alternative due to its better integration and increased performance. As well as the 8080’s seven registers and flags register, the Z80 had an alternate register set that duplicated them, two 16-bit index registers and additional instructions including bit manipulation and block copy/search.