have any documentation / example code on this?
Please use the VisualDSP On-line Help to obtain all the necessary information
on this. If you simply search for "Compiler Built-In Functions", you'll get a
few hits. The Compiler Built-In Functions in the Blackfin C/C++ Compiler and
Library Manual is what you are looking for.
This will provide you with a list of all the available intrinsics / built-in
functions supported by Blackfin. These functions enable efficient use of the
hardware resources. The C compiler intrinsic (built-in) functions are functions
that the compiler immediately recognizes and replaces with in-line assembly
code instead of a function call.
Furthermore, you will get another hit on "Compiler Performance Built-in
Functions", which maybe of help as well.