ip coregen
IP Cores are already developed design by third parties, which the designers can use in their design with/without paying usage fee. IpCoreGen is a core generator tool from Xilinx. This tool has a GUI, which is like a wizard. It helps user to select the required core (Eg: PCI Interface), configure the core (Eg: Clock speed, datawidth etc), choose the target device, choose the design language, netlist style, wrapper style etc...,
Once done, the tool creates the required files in the target directory. These are generally the netlist of the core, a wrapper to instantiate it in user's design, testbench and some documentation.