Sequential logic
Digital circuitry that generates outputs based on a combination of current inputs and past inputs is called sequential logic. This is in contrast to combinational logic, in which outputs depend only on the current state of the inputs. When a sequential logic circuit composed of several components operates those components under the control of a shared clock signal, the circuit implements synchronous logic.
The steps involved in the execution of processor instructions take place as a series of discrete operations that consume input in the form of instruction opcodes and data values received from various sources. This activity takes place under the coordination of a master clock signal. The processor maintains internal state information from one clock step to the next, and from one instruction to the next.
Modern complex digital devices, including processors, are almost always implemented as synchronous sequential logic devices. Low-level internal components, such...
