Not OP, but presumably, the answers are:

1) You don't... hence, my question about no nested function calls. If you push it anywhere else, you can call it whatever you want, but you just re-invented the stack. I _guess_ you could do some wierd stuff to technically not get a stack, but... again, it's wierd. And for what, again?

2) Some fixed address. If you have for example:

```c

typeRealBigStructure foo;

void baz(typeRealBigStructure * struct){

    // Do whatever to struct

void bar(void){

  baz(&foo);

```

The foo will probably end up in the BSS and will take up that space for the whole lifetime of the program. That's not the heap, not the stack, just... a fixed location in memory where the linker placed it.

I guess on big PC's stuff is very dynamic and you use malloc for a lot of stuff, but in embedded C, it's a very common pattern.

Ah, you're right, the struct case is actually pretty straightforward (especially since recursion is likely forbidden anyway), I just have trouble contorting my brain to such a different viewpoint.