Except ALUs share hardware with logic functions. Internally the adder (which is also used as a subtractor by ones complementing one of the inputs and inverting

Except ALUs share hardware with logic functions. Internally the adder (which is also used as a subtractor by ones complementing one of the inputs and inverting the initial carry in) uses xor, and you can implement the XOR logic op with the same gates. Also, modern ALUs don't use ripple carries really any more, but instead stuff like a Kogge-Stone adder (or really, typically a hierarchical set of different techniques). https://en.wikipedia.org/wiki/Kogge%E2%80%93Stone_adder https://en.wikipedia.org/wiki/Kogge%E2%80%93Stone_adder