-unit performs, the seven \hs{inputs}, and the address pair
-\hs{({-"a_0"-},{-"a_1"-})}:
+unit should perform, the seven \hs{inputs}, and the address pair
+\hs{({-"a_0"-},{-"a_1"-})}. It selects two inputs, based on the
+addresses, and applies the given operation to them, returning the
+result: