A method and apparatus for cutting a window covering comprises saw for cutting the window blind. The BTAC incorrectly predicts the branch instruction is wholly contained in the cache line; consequently, the microprocessor fetches from the target address without fetching the next sequential cache line containing the rest of the instruction. There is also a valve shaft disposed in the basic body. The transistor includes an oxide semiconductor film in contact with the oxynitride insulating film functioning as a base insulating film.