The Zilog Z80 is an 8-bit microprocessor designed by Zilog, first released in 1976; it played an important role in the evolution of early personal computing. It was designed to be software-compatible with the Intel 8080, offering a compelling alternative due to its better integration and increased performance. Along with the 8080's seven registers and flags register, the Z80 introduced an alternate register set, two 16-bit index registers, and additional instructions, including bit manipulation and block copy/search.