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

A method comprising:

• decoding an instruction, the instruction including an opcode, an immediate, and operands identifying a plurality of packed data source registers and a packed data destination register;
• adding each packed signed word from the first packed data source register with a selected packed signed word from the second packed data source register to generate a plurality of signed word results,
• each packed signed word from the second packed data source register selected for adding 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 packed data source register prior to the adder circuitry performing the adding;
• and
• storing the plurality of signed word results in specified data element locations of the packed data destination register.

A machine-readable medium having program code stored thereon which, when executed by a machine, causes the machine to perform the operations of:

• decoding an instruction, the instruction including an opcode, an immediate, and operands identifying a plurality of packed data source registers and a packed data destination register;
• adding each packed signed word from the first packed data source register with a selected packed signed word from the second packed data source register to generate a plurality of signed word results,
• each packed signed word from the second packed data source register selected for adding 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 packed data source register prior to the adder circuitry performing the adding;
• and
• storing the plurality of signed word results in specified data element locations of the packed data destination register.