The function
low-level-atomic-place-p
is the predicate for whether the place
place
is one of the places for which low-level atomic operations are defined, and is therefore suitable for use with those operators.
These places are described in Low level atomic operations.
atomic-decf
atomic-exchange
atomic-fixnum-decf
atomic-pop
atomic-push
compare-and-swap
define-atomic-modify-macro
LispWorks User Guide and Reference Manual - 21 Dec 2011