Help Needed : IP creation based on AMBA

[Jennis]

I suppose to create new IP based on AMBA but have no knowledge for this. Please excuse me for asking very basic questions but I really need those information. I know the verilog coding and verification process through VCS , but no idea about bus protocol and procedure to verify this. I gone through some links and found that C testcase is usually write to verify this , but did not get detail information. Could anyone give some idea why do I need to write C code (why can't be done in verilog/VHDL). What are the tools (besides VCS) are required to verify once I create the IP (in verilog format). What are the things need to be considered to create new IP.

Thanks in advance and for reading my post patiently.