First, thank you xilinx for moving the functionality previously available in Base-X to the free WebPack. I was somewhat confused by the literature on the website, but a call to support confirmed that the ISE
8.1 WebPack will support all Base-X devices, including the Virtex-4 FX12.
However, no one I talked to could confirm if it was possible to use the Virtex-4 hard EMAC primitive without coregen (which is unavailable in WebPack); I have managed to instantiate the "EMAC" in my VHDL design and get synthesis to run, but since I don't have silicon in front of me yet I can't "test" my design.
So, is it possible to just use the EMAC primitive like that, without coregen at all? I also can't simulate the part, as the SWIFT simulation models require an advanced ($$$) simulator, but that's a restriction I'm willing to live with.
...Eric