A method and apparatus for performing a shift operation on packed data elements having multiple values. One embodiment includes accessing the shift control signal of a first format from a memory. The shift control signal identifyies a first packed shift operation and whether the shift positions are byte positions or bit positions, and causes a processor to execute a set of control signals of a second format, thereby accessing the packed data, shifting the packed data by the number of shift positions according to the first packed shift operation, generating a first replacement data for one of the number of positions, and producing a shifted first packed data comprising the first replacement data.