RTOSes
embOS
Available for CPUs from 8 to 32bits.
Easily portable to any CPU at request.
One of the smallest and fastest kernel available.
No configuration needed.
No royalties.
Profiling support included.
The embOS trial version includes start projects for popular evalboards, the complete documentation, embOSVIEW etc.
Click below for Trial Version
http://www.segger.com/downloads.html