I came to announce my package [nint128](https://github.com/rockcavera/nim-nint128), 128-bit integers. It is not yet 100% (the basics are done), but it is already quite usable. The intention of the package is to always try to achieve the best possible performance.
I am currently testing on amd64 and i386. I have already made some performance improvements regarding multiplication and division. Feel free to help.