knowledge for noobs

How are procedure calls implemented? well you need to push a return address so that once the procedure completes it knows where to go back to, and you need to push all the parameters too, then you simple jump into the procedures code address.

And what is a tail call? its exactly the same as a normal procedure call except that the current stack frame is replaced or overwritten rather than a new one being created.

will cause a stack overflow if unoptimized

not on a Turing Machine!