Constant multiplier, method and device for automatically providing constant multiplier and storage medium storing constant multiplier automatic providing program

摘要

A constant multiplier reduces the number of partial products and thereby reduces the number of adding stages for a constant. By reducing the number of partial products, the constant multiplier reduces circuit area and operation delay. The constant multiplier is optionally incorporated into a corresponding method and a device which automatically provides the constant multiplier. The constant multiplier includes an adding/subtracting circuit, which has an adder and inverter, for performing addition and subtraction of partial products. Each of the partial products is obtained by multiplying each of “add” and “subtract” terms of a power of two having a smallest term number obtained by decomposing the constant by a signal. The constant multiplier is suitably used for designing a large scale integrated circuit (ASIC) having functions of a moving picture expert group (MPEG).