Is your feature request related to a problem? Please describe.
The classifier currently supports AVX2 only. It should be expanded to support SSSE3 instructions as a fallback for older x86 architectures.

Describe the solution you'd like
Since the vector width for SSSE3 is different than AVX2, we need a separate implementation that will work on shorter vectors. This probably means that the current implementation, where we consider two 32-byte AVX2 vectors at a time will have to be adapted to instead consider two 16-byte wide SSSE3 characters and use 32-bit wide masks.

This is a complex issue and requires careful measurement of performance impact. We will need to update all our benchmarks to accurately compare AVX2 and SSSE3 implementations.