Layout structure for barrel shifter with decode circuit

摘要

Two flip-flops and decode circuits are provided. Whereas the one flip-flop receives 1-bit bit-shift-amount data B(1), the other flip-flop receives 1-bit bit-shift-amount data B(0). The decode circuits decode the bit-shift-amount data from the flip-flops. The flip-flops and the decode circuits are laterally laid out in a line. The flip-flops and the decode circuits are symmetrically laid out in bits, together with four flip-flops that receive respective 1-bit data to be bit-shifted (data A(3) to A(0)) and a bit shifter that bit-shifts the data A(3) to A(0) for a bit shift amount from said decode circuits, to form a bit slice structure and to be arranged within a data path. Accordingly, it is possible to achieve an effective reduction of the length of signal wiring over which bit-shift-amount data propagate. The reduction of wire load can be accomplished. The speed-up of data bit shift processing can be realized.