Using Keil Compiler

Let's say I use uv-2 IDE
I say write a small a51 assembly program like this and add to proj
org 1000h
mov A,#05h
mov 90,A
end
If i want to simulate it and see the O/p of Port 1 where'd I see it?
Sorry if I sound like a n00b , but I searched the whole of KB and couldn't find such basic solns..btw, using AT89S8252