To change implementation options for NGDBuild, MAP, Post MAP TRACE, PAR, and Post PAR TRACE, go to the System tab in XPS. Under "Project Files" is a subtitle named "Implementation Options File: etc\fast_runtime.opt". Open this file and insert the additional option in the desired section.
By default, the implementation option settings for the MAP section look similar to the following:
Program map
-o <design>_map.ncd; # Output Mapped ncd file
-pr b; # Pack internal FF/latches into IOBs
#-fp <design>.mfp; # Floorplan file
<inputdir><design>.ngd; # Input NGD file
<inputdir><design>.pcf; # Physical constraints file
END Program map
For example, to add a CLB packing factor of "5" during the MAP stage, modify the above section as follows:
Program map
-o <design>_map.ncd; # Output Mapped ncd file
-pr b; # Pack internal FF/latches into IOBs
-c 5; # CLB Packing Factor: 5 <---------------
#-fp <design>.mfp; # Floorplan file
<inputdir><design>.ngd; # Input NGD file
<inputdir><design>.pcf; # Physical constraints file
END Program map
For incremental design, add the guide file switch "-gf system.ncd" in the PAR section of the implementations options file as described above.