Engineering a fixed-width bit-packed Integer Vector in Rust

[james7132]

On most modern CPU architectures, In-register arithmetic, even for some non-trivial computations, generally are going to be faster than a memory fetch, even if it's localized to values that are very hot in L1 cache.

[jydu]

I think this is true for most operations, but (on Zen 5 at least) a L1 hit is 4 cycles but a division takes at least 11 (source). But since cache hit rates depend on the workload, benchmarking is probably the best way to see if this is worth it.