DWCAS is not the same as DCAS which is specifically mentioned in your link, so I'm not sure which you're referring to. Second, the link is clear that no common

DWCAS is not the same as DCAS which is specifically mentioned in your link, so I'm not sure which you're referring to. Second, the link is clear that no common architecture actually supports a DCAS instruction currently, so the reason the author insisted on CAS is because it's a real life instruction and not a theoretical hardware instruction.