Indeed, I first learned about xor-swap from an example in the IBM System/360 Principles of Operations manual, circa 1968. (For some funky reason I don't underst

Indeed, I first learned about xor-swap from an example in the IBM System/360 Principles of Operations manual, circa 1968. (For some funky reason I don't understand, the Programming Examples section vanished from later editions of PrincOps.) I can't see any reason for wanting to use arithmetic instead.