function depth support

[vchau.2]

Hi All,

I want to know what is maximum function depth supported by STM32F417 in stmcube ide?

how function depth managed by stack pointer? 

[Ozone]

This is not exactly "function depth".

But yes, the critical parameter here is stack size, which is part of the specific project settings.
I don't use CubeIDE, so here an example from another toolchain / IDE:

In most cases, stack size is a parameter retrieved or shown during project creation, a.k.a. "project wizard".
Usually a default setting is presented you can edit at that time, or later on.

[vchau.2]

thanks for quick reply,

but my question in not belong to Stack size or stack over flow,

my Questions is -

1. how many C functions can be call in nested form?

2. How stack manage these nested functions by stack pointers

example:

int main()

{

func_1();

}

void func_1();

{

void func_2();

.

.

}

[KnarfB · Accepted solution]

There is no limit. The stack may overflow at run-time and this is not automatically detected and in your responsibility.

Here is a recursive function:

int ackermann(int n, int m) {
  if (n == 0)
    return m + 1;
  else if (m == 0)
    return ackermann(n - 1, 1);
  else
    return ackermann(n - 1, ackermann(n, m - 1));
}

ackermann(3,6) is 509. Calculating this results involves 2.986.490 recursive function calls (without optimizations). Finding the max. stack size used is left an exercise.

Learning abaout the stack in Cortex-M is a covered in books like "Definitve Guide..." by Joseph Yiu and online: 

• https://vuquangtrong.github.io/blog/stm32/stack-memory/
• How much Stack Memory do Cortex-M applications need - Architectures and Processors blog - Arm Community blogs - Arm Community

Happy reading

KnarfB

[vchau.2]

thanks for sharing such informative links....

that will be helpfull

[Ozone]

> 1. how many C functions can be call in nested form?

As much as the stack size allows.

In general, toolchains/IDEs are really bad at guessing runtime stack sizes. Set to a ball park figure according to code complexity, and increase if you encounter runtime overflows.
Standard library functions (like "printf()") have a significant impact, be aware.

Many RTOSes provide a runtime stack check option for their tasks, as a side note.

[Andrew Neil]

---

@vchau.2 wrote:

2. How stack manage these nested functions by stack pointers

---

That part is just standard Computer Science - nothing specific to CubeIDE or STM32.

It isn't even specific to C.

https://en.wikipedia.org/wiki/Stack_(abstract_data_type)#Compile-time_memory_management