Abstract: Signal propagation delay in an inverter chain having a first inverter cell and a second inverter cell connected by an intercell wire, is evaluated. In order to guarantee that a first inverter cell delay is always evaluated to be positive (A) a logic threshold voltage for an increase in input pin voltage of the first inverter cell is set to a voltage below a switching threshold voltage of the first inverter cell, and (B) a logic threshold voltage for a decrease in input pin voltage of the first inverter cell is set to a voltage above the switching threshold voltage of the first inverter cell. Similarly, logic threshold voltages for an increase and a decrease in input pin voltage of the second inverter cell are determined. Additionally, in order to guarantee that an intercell wire delay is always evaluated to be positive, logic threshold voltages for an output pin voltage of the first inverter cell are made to agree with the logic threshold voltages for the input pin voltage of the second inverter cell.

Abstract: An instruction is fed to first and second pipelines at a same time. The instruction is advanced in the first pipeline. In addition, the instruction is advanced in the second pipeline. Advance of the instruction in the second pipeline is controlled in accordance with a position of the instruction in the first pipeline to synchronize advance of the instruction in the first pipeline and advance of the instruction in the second pipeline.

Abstract: A data processing device includes first and second blocks which have different processing times and which operate in synchronism with a clock signal. One of the first and second blocks is selected and enabled in accordance with an instruction representing which of the first and second blocks should be selected and enabled. A clock change signal is generated on the basis of the instruction. A period of the clock signal is changed in accordance with the clock change signal.