Patent ID: 6360189
Filing Date: 2002-03-19
Classification: G06F

Abstract:
A data processing apparatus for performing a multiply-accumulate operation A+(B*C) in response to a single instruction identifying said multiply-accumulate operation, comprising:a multiplier for multiplying values B and C to generate an unrounded multiplication result, the multiplier adapted to generate first data required for rounding determination, said first data dependent upon said unrounded multiplication result; an adder for adding the unrounded multiplication result to a value A to generate an unrounded multiply-accumulate result, the adder adapted to generate second data required for rounding determination; determination logic for using the first and second data to determine one or more rounding values required to produce a final multiply-accumulate result equivalent to the execution of a separate multiply instruction incorporating rounding, followed by a separate add instruction incorporating rounding; and rounding logic for applying the one or more rounding values to generate the final multiply-accumulate result.