To insert buffers which compensate a driving force shortage for optimum positions by changing a scan chain, making the total wiring length short, reinserting the scan chain into a place where driving force is short, making the total wiring length short and inserting a buffer.
A scan chain initial generation processing inserts a scan in buffer and a pre-buffer and produces a scan chain making the scan in buffer as a start point and the pre-buffer as an end point through flip-flops(FF). Although a buffer is inserted between the FFs or between the FF and the pre- buffer where wiring length exceeds a limitation value because a clock rate for the scan can not be guaranteed if when the wiring length exceeds the limitation value at which the wiring length becomes short in driving force, the buffer is inserted between blocks where the wiring length is estimated to exceed the limitation value because a wiring position is not decided yet at the point of this time. Thus, the scan in buffers 330 and 331 and the pre-buffers 341 and 342 are inserted and also buffers 370 to 372 are inserted to cross between the blocks.
KONDO KAZUHIRO
YUYAMA YASUSHI
MOCHIZUKI MASAKAZU
HAMACHI CHIHARU
HITACHI COMMUNICATION SYSTEM