in order to store sufficient state to resume operation should an
interrupt occur. this is also why implementations are permitted to use
the destination vector to store intermediary computations
+7. *Predication may be applied*. zeroing mode is not an option. masked-out
+ inputs are ignored; masked-out elements in the destination vector are
+ unaltered (not used for the purposes of intermediary storage); the
+ scalar result is placed in the first available unmasked element.
TODO: Rc=1 on Scalar Logical Operations? is this possible? was space
reserved in Logical Ops?