A method and apparatus for including in a processor instructions for performing select operations on packed or unpacked data. In one embodiment, a processor is coupled to a memory. The memory has stored therein first packed data in a source operand and a second packed data in a destination operand. The processor selects the first packed data if the control bit for the source operand is set to “1” and stores the data into the destination operand. Otherwise, the processor keeps the data in the destination operand. The final value of the destination operand is stored in memory.