0: c <- a - c
1: IF b <= 7 THEN
2: IF a == d THEN
3: b <- a
4: a <- b
GOTO 7
ELSE
GOTO 2
FI
ELSE
5: a <- d
6: IF d <= b THEN
GOTO 5
ELSE
7: c <- b
8: d <- c
9: d <- b
GOTO 0
FI
FI