First pass poor man’s SIMD approach, works only for 4 bytes, next step is to work across whole arrays.
Full implementation of the ‘poor man’s’ SIMD approach to memset.

Shave’s roughly 2ms off the overall time, probably could be better. A v3 will use the SIMD instructions.
Shell for atoi
Optimisation that shaves 5ms of the wall time compared with version 1 approach in common case.
Implementation of atoi with error checking for non-numeric ASCII codes.
Address the '+' prefixed numbers