Delay library representation method, delay library generation method and delay calculation method using the delay library

In order to perform precision delay calculation of a signal of small signal-swing, a delay library in consideration of the small signal-swing making no full swing is generated. It is assumed that a signal having a rising edge and a step waveform which lags the rising edge by a fixed time interval and a signal having a step waveform and a falling edge which lags the step waveform by the fixed time interval are entered as an input signal to a cell. The driving ability of the cell is represented by a function or in a table having as parameters the slews of the rising and falling edges, the fixed time interval and the load capacitance driven by the cell.