*        do i=1 to 8 by 2
         L      3,1                r3 index and start value 1
         LA     4,2                r4 step 2
         L      5,8                r5 to value 8
LOOPI    EQU    *
         ...                       loop 4 times (r3=1,3,5,7)
         BXLE   3,4,LOOPI          r3=r3+r4; if r3<=r5 then loop