Microsequencer

In the field of computer architecture and Engineering, a sequencer or microsequencer, is a part of a control unit of a Central processing unit. It generates the addresses used to step through the Microprogram of a control store. Usually the addresses are generated by some combination of a counter, a field from a microinstruction, and some subset of the instruction register.

A counter is used for the typical case, that the next microinstruction is the one to execute.

A field from the microinstruction is used for jumps, or other logic.

Since CPUs implement an instruction set, it s very useful to be able to decode the instruction s bits directly into the sequencer, to select a set of microinstructions to perform a CPU s instructions.

Most modern CPUs are considerably more complex than this description suggests. They tend to have multiple cooperating micromachines with specialized logic to detect and handle interference between the micromachines.