Hi
  I tried to synthesize PCI core in Xilinx ISE 
  4.1, but it says that:
   
  "ERROR:Xst:996 - wb_addr_mux.v Line 165. 
  Undefined Text Substitution macro 'undef'
--> 
EXEWRAP detected a 
  return code of '6' from program 'C:/ISEFndtn/bin/nt/xst.exe'
   
  Done: failed with exit code: 
  0006."
   
  I'm not oriented in verilog, rather VHDL, I 
  think that "'undef" is directive that ISE doesn't understand
  or I should setup any of synthesize 
  options?
  How to resolve this?
   
  Best regard
   
  Jurek