Would it not be simpler to bitwise OR every 5th bit to one based on a byte mask for uppercase chars? Also, use SIMD - I think even AVX can do byte level parale

Would it not be simpler to bitwise OR every 5th bit to one based on a byte mask for uppercase chars? Also, use SIMD - I think even AVX can do byte level paralellism for 256 and 512 bits at a time?