How to generate eye diagram in HSPICE

Because I am doing PLL/DLL design, I need to generate eye diagram in HSPICE.
Please paste the following sentences (red words) in your netlist and then run simulation.
.param period='10n $set eye diagram periodiod
.param t_start='0.1m' $set eye diagram start time
.probe tran eyetime=
+par('.5*(sgn(TIME-t_start)+abs(sgn(TIME-t_start)))*(TIME-t_start-period*int((TIME-t_start)/period))')

After simulation is done, please open the waveforms in AWAVES.
Set the parameter "eyetime" as your x-axis and display the waveforms that you want to see.
Now, the waveform is the eye diagram format.