(I hope :LISPWORKS-64BIT exists. I don't have a 64-bit Lisp to
test with.)
The :LISPWORKS-64BIT feature does exists. My *features* contains
(among others of course):
:COMMON-LISPWORKS :LISPWORKS :LISPWORKS5 :LISPWORKS5.0 :LISPWORKS-64BIT
Cheers,
Chris Dean