Thanks for the reply to both of you :)
Yea i find that if I issue "run 400" it shows the complete simulation result.
That means that when we are issuing "run" command, the compiler executes only uptil a certain time instant ....
And that's now a concern...how does the compiler decide this time for which simulation is done for a single "run" command.
One observation is , if I change the timescale to :
'define timescale 1ns/1ns
and then do : run
I get the complete results at once....ie at least upto simulation time 31 ns....
run
# 0 x
# 20 1
# 31 0
So the question that bothers is how we know what is this timestep that "run" command executes for ?
Thanks a lot again !