Hi,
I did the port of the armv7 rtems port.
The stdlib uses OS services to implement it’s functionality. For example POSIX. However, there are differences in POSIX implementations depending on OS (e.g. FreeBSD, Linux) as well as targets (architectures as well as which C library is used).
So, one thing was to figure out which code paths of the stdlib to enable via the config switches).
The POSIX flavor of the stdlib then also depends on C bindings for the actual structs, types and functions which the target OS uses. These are collected in the libc FFI library.
So, for adding a new RTEMS target the already ported parts of the stdlib from the armv7 port should be reuseable as the config switches are only related to the OS. You would need to add the correct bindings to the libc library for a new architecture, though.
The big chunk of work I see, is to run the stdlib unit testsuite on the (emulated) target, so that we get an idea which parts of the stdlib actually work on RTEMS and where futher fixes are necessary. So, far I only tested it with some custom simple “Hello World” and very simple unit tests.