Patent ID: 8904152

Claim:
A method for operating a complex multiplication unit, the method comprising: initiating operation of a complex multiplication unit in response to a processor issued complex multiplication instruction that identifies source operands of a first complex number, source operands of a second complex number, and a rounding mode; multiplying the source operands of the first complex number by the source operands of the second complex number according to complex number arithmetic to produce a first real result and a first imaginary result; rounding the first real result to produce a rounded real result and rounding the first imaginary result to produce a rounded imaginary result, wherein the rounding operates according to the rounding mode; and selecting a first group of most significant bits (MSBs) of the rounded real result to produce a real result and selecting a second group of MSBs of the rounded imaginary result to produce an imaginary result, wherein the first group of MSBs and the second group of MSBs are selected according to a data format of the source operands.