run
-ifmt VHDL
-ent fifo_4k_2clk_exdes 
-p xc6slx75-csg484-2
-ifn xst.prj
-write_timing_constraints No
-iobuf YES
-max_fanout 100
-ofn fifo_4k_2clk_exdes 
-ofmt NGC
-bus_delimiter ()
-hierarchy_separator /
-case Maintain
