Printing Stack and Heap pointers

RE: Printing Stack and Heap pointers

bjorn-spockeli — Wed, 04 Jan 2017 12:23:08 GMT

Yes, that is Keil specific, so just ignore it.

RE: Printing Stack and Heap pointers

Jawad — Wed, 04 Jan 2017 12:22:11 GMT

Thanks Bjorn,

Regarding your comment that "Use MircroLib under "Options for Target". Is it something related to Keil? I am using Eclipse and can't find it.

Thanks

RE: Printing Stack and Heap pointers

bjorn-spockeli — Wed, 04 Jan 2017 11:34:39 GMT

You could look into the __heapstats function, see this link. Just make sure that you include stdlib.h and uncheck Use MircroLib under "Options for Target".

RE: Printing Stack and Heap pointers

Jawad — Wed, 04 Jan 2017 10:40:58 GMT

Thanks RK,

I am using nrf52 IoT SDK implementation for MQTT with following malloc

void * nrf_malloc(uint32_t size){

uint8_t * buffer = NULL;
uint32_t allocated_size = size;

uint32_t retval = nrf_mem_reserve(&buffer, &allocated_size);

if (retval != NRF_SUCCESS)
{
    buffer = NULL;
}

return buffer;

}

RE: Printing Stack and Heap pointers

RK — Wed, 04 Jan 2017 10:36:18 GMT

There's a CMSIS defined function __get_PSP() which should get the stack pointer for any supported compiler, it uses the MRS instruction to do it.

The heap pointer however, that depends entirely on what malloc implementation you're using.

RE: Printing Stack and Heap pointers

Jawad — Wed, 04 Jan 2017 10:15:03 GMT

Hi Bjorn,

Thanks for the comment. I was not using heap before but now for the nrf52 implementation for mqtt I need to use the calloc and malloc functions for which I need heap. That's why I want to print heap pointer.

Thanks

RE: Printing Stack and Heap pointers

bjorn-spockeli — Wed, 04 Jan 2017 10:09:25 GMT

Hi Jawad,

a quick-and-dirty way of obtaining the value of the stack pointer is to push a variable to the stack and then print the address of said variable, i.e.

void print_stack_pointer() 
{
  uint32_t * ptr = NULL;
  NRF_LOG_INFO("%p \n", (uint32_t)&ptr);
}

I am not sure if you can use the same approach to get the current heap pointer , but I thought that you were'nt using the heap since this is related to this and this question.