Writing application programs for NIOS II

Hello all,

Im a hardware engineer. As of now i'm working on NIOS II processor in which i need to develop both hardware and software for ethernet communication. My requirement is to read data from the 3 PIOs peripheral of NIOS II and send it to TSEMAC to packetize the data and send it to through PHY device. I went through the example simple socket server application progam which comes along with the nioseds, but i'm finding it very difficult to understand.. Can somebody help me out in this regard where to start and how to go about in developing a application program for the above requirement. I'm not able to understand the OS function calls and why it is required.. Any helping hand in this regard is highly appreciated..

Thanks,