Patent ID: 8195975

Claim:
A semiconductor integrated circuit device comprising: a plurality of operation units connected in a pipeline structure, each performing an operation processing on data; a process control unit that operates in synchronization with a system clock signal and generates a process control signal for controlling the operation units upon receiving a data notification signal that notifies an arrival of data from outside; and a clock-control signal generating unit that operates in synchronization with the system clock signal and generates a clock control signal for controlling a clock supply to each of the operation units upon receiving the process control signal, wherein each of the operation units includes a clock gating circuit that operates in synchronization with the system clock signal and generates a gated clock signal for operating the operation unit based on the clock control signal, an operation block that operates in synchronization with the gated clock signal, performs a processing instructed by the process control signal on the data upon receiving the data and the process control signal, and outputs processed data and the process control signal to a subsequent operation unit, and an output circuit that outputs the clock control signal to the subsequent operation unit upon receiving the clock control signal such that the clock control signal is synchronized with the processed data and the process control signal, wherein the clock control signal includes a first clock control signal and a second clock control signal, the first clock control signal indicates to perform the clock supply when the process control signal indicates an execution of a processing, and otherwise, not to perform the clock supply, the second clock control signal indicates to perform the clock supply when the process control signal indicates an execution of a processing and a content of the processing is different from a content of a previously executed processing, and indicates not to perform the clock supply when the process control signal indicates an execution of a processing, a content of the processing is same as a content of a previously executed processing, and the process control signal does not indicate an execution of a processing.