The fanciness of expressing these as signed constants probably hurted
the understandability of the code more than it helped.
Part of P0189, funded by Arandui and Lmocinemod.
Adding op/, main/, and end/ directories does nicely cover a great
majority of the "not really further classifiable slices" implied in
d56bd45.
Part of P0086, funded by [Anonymous] and Blue Bolt.