System and method of using common adder circuitry for both a horizontal minimum instruction and a sum of absolute differences instruction

摘要

A system which uses common adder circuitry to perform either one of a horizontal minimum instruction and a sum of absolute differences instruction including multiple adders, a sum circuit, a compare circuit, and a routing circuit. The input operands include multiple digital values which are delivered by the routing circuit to the adders depending upon which instruction is indicated. Each adder determines a difference between a pair of digital values. The differences are grouped and summed together by the sum circuit for the sum of absolute differences instruction. The adders are paired together for the horizontal minimum instruction, in which each pair provides carry and propagate outputs. The upper portions of a pair of digital values are compared by the upper adder and the lower portions are compared by the lower adder, and the carry and propagate outputs are collectively used to determine the minimum value.