Microsequencer

In the field of computer architecture and engineering, a sequencer or microsequencer, is a part of a control unit of a CPU. 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.

Related Topics:
Computer architecture - Engineering - Control unit - CPU - Microprogram - Control store - Instruction register

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

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

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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.

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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.

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