Receive packed data operation mask comparison instruction indicating first packed data operation mask having first packed data operation mask bits and second packed data operation mask having second packed data operation mask bits. Each packed data operation mask bit of first mask corresponds to a packed data operation mask bit of second mask in corresponding position. Modify first flag to first value if bitwise AND of each packed data operation mask bit of first mask with each corresponding packed data operation mask bit of second mask is zero. Otherwise modify first flag to second value. Modify second flag to third value if bitwise AND of each packed data operation mask bit of first mask with bitwise NOT of each corresponding packed data operation mask bit of second mask is zero. Otherwise modify second flag to fourth value.