;; This program reads in a sequence of positive
;; integers terminated by a non positive integer.
;; It counts the number of positive input integers <= 21
;; and prints that number out.
;;
;; Date Written: 2008/02/13
;; Author: Jordan Barry


allocate-registers count, zero, age, legal-age, end, loop-start, sentinel, legal?

li count, 0
li zero, 0
li legal-age, 21
li end, Lend
li loop-start, Lloop
Lloop:
read age
sgt sentinel, age, zero
jeqz sentinel, end
slt legal?, age, legal-age
add count, count, legal? ; legal? will have 1 if under age, 0 if it isn't
j loop-start
Lend:
write count
halt