I want to use the FreeRTOS on the ARM Cortex-M4 based FPGA subsystem. I am looking for the option in which I can utilise the the existing files with some modifications related to our mamory map and interrupt structure. Initially I am thinking of using startup files provided by CMSIS2.0 But I am not sure, whether it will be a good starting point or not. Can I use the existing Cortex-M3 startup files and modify them for my system.
Very briefly - you have not provided enough information for me to provide a complete answer (for example, which compiler are you using? Which FPGA is it on?) - existing Cortex M3 ports will run fine or Cortex M4 provided you are not using the hardware floating point, or if you are, not from more than one task. An M4 port with hardware floating point support is planned shortly.