xst -intstyle ise -ifn "G:/Work/FPGA_CD/chapter4/exp4_1/adder_top.xst" -ofn "G:/Work/FPGA_CD/chapter4/exp4_1/adder_top.syr" 
xst -intstyle ise -ifn "G:/Work/FPGA_CD/chapter4/exp4_1/adder_top.xst" -ofn "G:/Work/FPGA_CD/chapter4/exp4_1/adder_top.syr" 
