National Research Development Corporation

Kenneth W Wood

John G McWhirter

John V McCanny

A digital data processor is provided to multiply data elements by coefficients. It includes a systolic array of cells consisting of nearest neighbor connected gated full adders. The cells multiply data bits received from laterally adjacent cells and subsequently pass them on. The product is added to a cumulative sum bit from a cell above and to a carry bit recirculated from an earlier computation. The output is passed to a cell below, and a new carry bit is recirculated for addition in a subsequent computation. Data and coefficients are input in counterflow to opposite sides of the array. An adder tree accumulates non-simultaneously computed contributions to individual output terms. The tree incorporates a delay and switches arranged to implement or bypass the delay according to earlier or later computation of a contribution. By virtue of this accumulation, the processor provides reduced cell redundancy compared to the prior art.

Digital data processor for multiplying data by a coefficient set

A digital data processor for matrix/matrix multiplication includes a systolic array of nearest neighbor connected gated full adders. The adders are arranged to multiply two input data bits and to add their product to an input cumulative sum bit and a carry bit from a lower order bit computation. The result and input data bits are output to respective neighboring cells, a new carry bit being recirculated for later addition to a higher order bit computation. Column elements of one matrix and row elements of the other are input to either side of the array bit-serially, least significant bit leading, for mutual counterpropagation therethrough with a cumulative time delay between input of adjacent columns or rows. Bit-level matrix interactions for product matrix computation occur at individual cells. Pairs of intercalated adder trees are connected switchably to the array to accumulate bit-level contributions to product matrix elements.

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Newcastle-upon-Tyne, United Kingdom

Kenneth W Wood