This project is easily my personal record for having the highest ratio of INTERCAL code to documentation. Normally an INTERCAL program requires a fair bit of explanation in order to use. However, this set of five libraries needs none, as each one is simply a direct port of the standard INTERCAL system library, already documented in the manual.
The C-INTERCAL compiler introduced support for non-binary bases in its wild adolescent era, but for many years afterwards there was no system library available in those other bases. It was therefore extremely difficult to get anything done in them, even if you had a solid grasp of the non-binary logical operators. Frustrated with this ridiculous situation, I eventually sat down and started porting the system library.
Originally I was only going to port the ternary version, but once I had finished that one, I realized that it was never going to be easier to do the other four than it was right then, while the specifics of the routines were still fresh in my mind. So I kept going until I had all of them done.
Each library after the ternary version got bigger and slower, as each higher base required more logical operations in order to do multiplication and division. The library uses labels in the 1700s to store internal subroutines. The one for base 7 is particularly cumbersome. (If you are writing septary INTERCAL and are frustrated with the slow speed of the multiplication and division routines, I apologize, while also suggesting that if you can do significantly better then please share your code with the rest of the class.)
The entire project took most of a summer. Two memories from that time stick out in particular. The first is of being trapped in an airport for several hours waiting for a connecting flight to arrive. I wound up using that time to start composing the quartary library, writing several pages of INTERCAL code in pencil in my notebook. The second memory is from when I was porting the sexary libray. After finishing the port, testing revealed a bug that I hadn't seen before and didn't understand. Later that week I was out drinking with friends when a possible cause for the bug suddenly popped into my head. I went home hours later, and although I was quite inebriated by then I was able to recall the idea and successfully fix the bug. (I have never worked on code while intoxicated to that degree before or since.)
The link at top will download a tarball containing the full set of libraries. However, they are included as part of the C-INTERCAL compiler distribution, so if you have the compiler you should already have the libraries. As with the original binary system library, the compiler automatically includes the library if any of its routines are invoked.