Microcode

Microcode is a set of low-level micro-instruction sequences stored in a processor's control store, used to translate and decompose complex machine instructions into elementary micro-operations that the processor hardware can execute directly. It serves as an intermediate layer between hardware and the instruction set architecture, making processor design more flexible and facilitating instruction set extension and error correction. Microcode is especially significant in CISC architectures and can also be updated via firmware to modify processor behavior or patch security vulnerabilities.