(DUMMY SUBROUTINE)
O100 sub
O100 return
O100 endsub

(MAIN SUBROUTINE)
O200 sub
G00 X#1 Y#2 Z#3
O100 call
(#1 #2 and #3 are now corrupted upon return from dummy subroutine)
G00 X#1 Y#2 Z#3
O200 endsub

(MAIN)
O200 call [1] [2] [3]
M02