Each real time kernel port consists of three files that contain the core kernel
components and are common to every port, and one or more files that are 
specific to a particular microcontroller and/or compiler.

+ The FreeRTOS/Source directory contains the three files that are common to 
every port list.c, queue.c, and tasks.c.  The kernel is contained within these 
three files.  croutine.c implements the optional co-routine functionality, which
is normally only used on very memory limited systems.

+ The FreeRTOS/Source/Portable directory contains the files that are specific to 
a particular microcontroller and/or compiler.

+ The FreeRTOS/Source/include directory contains the real time kernel header 
files.

See the readme file in the FreeRTOS/Source/Portable directory for more 
information.