ARITHMETIC UNIT FOR SUM OF PRODUCT

摘要

PURPOSE:To reduce only one adder as compared to an ordinary unit and to shorten an arithmetic processing time by adding the outputs of an accumulator by a Wallace tree adder together with the addition of partial products. CONSTITUTION:Input data to be the 1st data and factor data to be the 2nd data are supplied to terminals 1a, 1b respectively. A partial product formation circuit 2 forms the partial products of respective data on the basis of the Booth's method of 2 bits and the Wallace tree adder 7 adds the outputs of the accumulator 6 simultaneously with the addition of the partial products. The output of the Wallace tree adder 7 is supplied to a carry foreseeing adder 4 and its outputs are accumulated and outputted in/from the accumulator 6 as the calculated result for the sum of products. Said operation is sequentially repeated and the calculated result for the sum of products of all data is outputted.