Hand crafted a simple strchr and comparing it with Libc: https://wiki.linaro.org/WorkingGroups/ToolChain/Benchmarks/InitialStrchr
It's interesting it's significantly faster than libc's on A9's, but on A8's it's slower for large sizes. I've not really looked why yet; my
implementation is just the absolute simplest thumb-2 version.
Did some ltrace profiling to see what typical strchr and strlen sizes were, and got a bit surprised at some of the typical behaviours
(Lots of cases where strchr is being used in loops to see if another string contains anyone of a set of characters, a few cases
of strchr being called with Null strings, and the corner case in the spec that allows you to call strchr with \0 as the character
to search for).
Trying some other benchmarks (pybench spends very little time in libc,package builds of simple packages seem to have a more interesting
mix of libc use).
Sorting out some of the red tape for contributing.
Dave