> Unfortunately, this requires writing assembly, because writing high-performance arithmetic is not possible in Go — it's simply not a design goal of the language. (There are a few reasons, most notably that there's no way to directly compute the (128-bit) product of 64-bit integers.)

Can any language do this, without also calling through some library that has hand-crafted assembly in it? Will assigning the product of 2 longs in C to a long long result in the correct instructions?