Apparatus and method for adding packed data elements with rotation and halving

Abstract

An apparatus and method for performing addition of signed packed data values using rotation and halving. For example, one embodiment of a processor comprises: a decoder to decode an instruction to generate a decoded instruction, the instruction including an opcode, an immediate, and operands identifying a plurality of packed data source registers and a packed data destination register a first source register to store a first plurality of packed signed words; a second source register to store a second plurality of packed signed words; execution circuitry to execute the decoded instruction, the execution circuitry comprising: adder circuitry to add each packed signed word from the first source register with a selected packed signed word from the second source register to generate a plurality of signed word results, the adder circuitry to select each packed signed word from the second source register in accordance with a rotation value in the immediate of the instruction, the rotation value to indicate an amount of rotation to be applied to the packed signed words in the second source register prior to the adder circuitry performing the adding; and a destination register to store the plurality of signed word results in specified data element locations of the destination register.