Multiply circuit and method that detects portions of operands whose partial products are superfluous and modifies partial product manipulation accordingly

摘要

Multiplication circuitry performs a multiply operation to multiply a multiplicand operand and a multiplier operand to form a total product of the multiplication operation, where the multiplier operand includes a plurality of multiplier operand portions. The multiplication circuitry includes multiplier circuitry configured to multiply each of the multiplier operand portions and the multiplicand operand, in a sequence, to form a sequence of partial products corresponding to the sequence of multiplier operand portions. The multiplier circuitry further includes combining circuitry configured, for each multiplier operand portion, to combine the partial product corresponding to that multiplier operand portion with a previous partial result, to generate a new partial result corresponding to that multiplier operand portion. Detection circuitry is configured to determine, for each multiplier operand portion and based on that multiplier operand portion, if the new partial result corresponding to that multiplier operand portion would not affect the final result of the multiplication. For example, the detection circuitry may be specifically configured to determine whether the multiplier operand portion is all zeros or all ones. Control circuitry is configured to control operations of the combining circuitry responsive at least to the determination of the detection circuitry for that multiplier operand portion.