Pops an item from the stack. If true, execute the following statements. If false, jump to the statement following 'endwhile'.

5 ->y 
while 
	<-y gt(0) 		#is y greater than zero? 
repeat 				#repeat this section of code 
	trace(<-y) 
	<-y sub(1) ->y 	#subtract 1 from y so we don't end in infinite loop 
endwhile