You didn't give me the public share link though, and i dont use microsoft word < we dont have write access ofcourse to your docs 
Basically any cpu with a call stack can handle multiple execution layers, like say an OS/file manager that points to a particular program. So if you return from the program you pop the recent value from the stack and you can continue from that point on. Though do keep in mind that you cannot interrupt the program from outside, it has to terminate on its own. If you do want more flexibility on this you should consider looking up context switching among other things.
Don't overdo it
one step at a time plz
as for pipelining ask me or Lorddecapo, we both know a great deal and no you dont need extra instructions for that. It will give you more headaches though
Basically any cpu with a call stack can handle multiple execution layers, like say an OS/file manager that points to a particular program. So if you return from the program you pop the recent value from the stack and you can continue from that point on. Though do keep in mind that you cannot interrupt the program from outside, it has to terminate on its own. If you do want more flexibility on this you should consider looking up context switching among other things.
Don't overdo it
one step at a time plzas for pipelining ask me or Lorddecapo, we both know a great deal and no you dont need extra instructions for that. It will give you more headaches though