The ABD algorithm. 1R1W register.
Attiya, Hagit, Amotz Bar-Noy, and Danny Dolev. "Sharing memory robustly in message-passing systems." Journal of the ACM (JACM) 42.1 (1995): 124-142.
https://www2.cs.ucy.ac.cy/~nicolasn/epl432/Readings/attiya2004.pdf