I mean saving the address for control to return to so that the subroutine never has to know or care; it just executes the RET instruction. And RET is just POP+J

I mean saving the address for control to return to so that the subroutine never has to know or care; it just executes the RET instruction. And RET is just POP+JMP. This is super handy--so handy that alternative control strategies aren't explored as much as they might have been otherwise.