tree db813c3f8bf697bdb07120789bbe13edcfff3d8f
parent f2de8afd2bf6daddf31a52a459737889aea0e4bb
author Rich Lane <rlane@bigswitch.com> 1404174239 -0700
committer Rich Lane <rlane@bigswitch.com> 1404174645 -0700

change checksum combination operation to addition

Addition/subtraction has advantages over XOR in that two adds of the same value
don't cancel each other out, and the high bits are better utilized.