: fp-env-register ( -- register ) (fp-env-registers) first ;
-:: mask> ( bits assoc -- symbols )
- assoc [| k v | bits v mask zero? ] assoc-reject keys ;
+: mask> ( bits assoc -- symbols )
+ [ mask zero? ] with reject-values keys ;
: >mask ( symbols assoc -- bits )
over empty?
[ 2drop 0 ]