The main source of information is the newlib website (sourceware.org/newlib). This includes a FAQ, which has brief instructions on porting newlib and documentation for libc [1] and libm, the two libraries making up newlib. The libc documentation is particularly useful, because it lists the system calls which must be implemented by any new port, including minimal implementations.

The newlib README is another source of information. Key header files within the source also contain useful commenting, notably ieeefp.h and reent.h.

There is also a mailing list, <newlib@sourceware.org> where questions can be asked, or new ports submitted.

This application note does not cover the detail of testing newlib on physical hardware. That subject is well covered by Dan Kegel's Crosstool project [2].

This application note has drawn heavily on these sources, and the author would like to thank the providers of that original information.