Add support for padd* and pandn instructions

[ddash-ct]

Add support for PADD* - Add Packed Integers and PANDN - Logical AND NOT instructions.

Preliminary implementation looks like:

def paddb(ctx: ProcessorContext, instruction: Instruction):
    """
    Add packed integers

    :param ProcessorContext ctx: Processor context
    :param Instruction instruction: Instruction


    :return:
    """
    operands = instruction.operands
    opvalue1 = operands[-2].value
    opvalue2 = operands[-1].value
    result = (opvalue1 + opvalue2) & 0xffffffffffffffffffffffffffffffff
    logger.debug("0x%X + 0x%X = 0x%X", opvalue1, opvalue2, result)
    operands[0].value = result


def pandn(ctx: ProcessorContext, instruction: Instruction):
    """
    Logical AND NOT

    :param ProcessorContext ctx: Processor context
    :param Instruction instruction: Instruction


    :return:
    """
    operands = instruction.operands
    opvalue1 = operands[-2].value
    opvalue2 = operands[-1].value
    result = (~opvalue1 & opvalue2)
    logger.debug("~0x%X & 0x%X = 0x%X", opvalue1, opvalue2, result)
    operands[0].value = result