how can we detect a stack overflow

[Elctro1]

Hi,
I work with the 8051 microcontroller (using the Keil compiler), and I’m a bit stuck on one thing detecting stack overflow.


I know the stack is pretty limited in 8051, and if it overflows, things can get messy (corrupting SFRs and all that). But how do I actually check if a stack overflow is happening?


Are there any built-in tools in Keil for this? Or maybe some clever trick or best practice to monitor stack usage at runtime?

 

[Nigel Goodwin]

If you're using a C compiler, than presumably the compiler takes care of that?.

 

[Papabravo]

The problem is overhead. There is no hardware mechanism for detecting this condition. For every stack access, you need to check that the SP (Stack Pointer) register is within limits before and after the operation. This will also detect underflow which is equally undesirable. I've spent half a century on embedded systems development and never found a need to do this on the 8051 and its derivatives as well as many other devices.

No compiler that I ever used for developing 8051 code was capable of knowing how to do this check at compile time. I have seen other compilers that check for recursive function calls, but you rarely see them in embedded applications. Analyzing data operations on the stack is more difficult and again not a common feature in 8051 compilers or applications.

 

[danadak]

Some ref material, not 8051 centric

How to Detect, Debug and Prevent Stack-Overflow!

Today I ran into my very first stack overflow bug. It was a frustrating experience to find the actual bug as I had to go through all of my code and double-check the logic, buffers, pretty much my entire code before I was finally able to detect that the bug I got was due to ... Read more

embeddedinventor.com

Compiler based detection -

FreeRTOS stack usage and stack overflow checking - FreeRTOS™

FreeRTOS stack usage and stack overflow checking

www.freertos.org

Cortex-M hardware stack overflow detection - Page 1

Cortex-M hardware stack overflow detection - Page 1

www.eevblog.com

8051 centric -

8051 Stack Operations: Push to the Limit - Embedded Flakes

In this comprehensive guide, we'll dive deep into the intricacies of 8051 stack operations, exploring how to utilize the microcontroller to its maximum potential.

embeddedflakes.com

Regards, Dana.

 

[ahsrabrifat]

Hi,
I work with the 8051 microcontroller (using the Keil compiler), and I’m a bit stuck on one thing detecting stack overflow.


I know the stack is pretty limited in 8051, and if it overflows, things can get messy (corrupting SFRs and all that). But how do I actually check if a stack overflow is happening?


Are there any built-in tools in Keil for this? Or maybe some clever trick or best practice to monitor stack usage at runtime?

Did you try to set a maximum stack size in Keil?

 

[Ian Rogers]

Kiel compiler should warn of the eminent overflow as it will estimate the usage when it compiles.

If you have the basic 256 byte stack and you are passing parameters as if they are going out of fashion, then yes! The limit will be reached fairly quickly. However!!!! if you are using interrupts, the compiler cannot determine stack overflow. that I'm afraid is your lookout!

If you increase the stack then you'll be loosing ram.. If you are efficient with pointers, you should only need a small stack or if you use global variable rather than locals.. On an 8 bit, returning in's and long's also cause headaches. If you use functions as they should be used to pass pointers and return characters. The return should only be boolean ie. did work / didn't work...

If you use printf in your code..

returns a char but, printf( buffer," hello this is a string"); has just used 27 bytes. once you know, you can kerb your stack usage.