The 'A' is for 'Accelerated': Checking ASCII with SWAR

In this post, discover how to push Haskell’s performance boundaries by using SWAR (“SIMD Within A Register”) techniques to validate ASCII data in bulk. You’ll see how packing bytes into registers—using bit masking to flag non-ASCII values in parallel—and unrolling loops to leverage the CPU’s superscalar engine both drive down overhead. By the end, we'll transfer a simple foldl'-based ASCII detecting function into a version running 10x faster.