US Patent 10089078 Circuit for performing a multiply-and-accumulate operation

A circuit includes a multiplier, an adder, a first result register and a second result register coupled to outputs of the multiplier and the adder, respectively. The circuit further includes: a first selection unit configured to selectively provide, to the multiplier and in response to a first control signal, a first value from a first plurality of values; and a second selection unit configured to selectively provide, to the multiplier and in response to a second control signal, a second value from a second plurality of values. The circuit also includes: a third selection unit configured to selectively provide, to the adder and in response to a third control signal, a third value from a third plurality of values; and a fourth selection unit configured to selectively provide, to the adder and in response to a fourth control signal, a fourth value from a fourth plurality of values.