[tresta]

Why wouldn't it?

A xor A = 0.

A xor 0 = A.

That should work like a regular circularly linked list or am I missing something?

edit

Doh, now I understand. If this was allowed it wouldn't be possible to have a one-node non-circular list.

[bbrtyth]

It would be the reverse case if it were non-circular, returning 0.

[ithkuil]

You can encode "end of list" with another value like -1 which is usually safe since you can assume that addresses are at word aligned (so odd numbers cannot be addresses)