STM32F417 Stack memory

[New.Fish]

My application use lots of RAM, I'm concern about the stack memory.

The RAM size is  128KB,from 0x20000000 to 0x20020000.

Form the linker script (.ld) file,

_Min_Heap_Size = 0x200; /* required amount of heap */
_Min_Stack_Size = 0x400; /* required amount of stack */

Use "Build Analyzer" to check Memory Details, it says "._user_heap_stack  Run Address  0x2000d160     1.5K ".

But when I run the debugger, SP starting at 0x20020000; when call functions it goes to 0x2001ffe8; 0x2001ffe0...

My question are:

1. The ._user_heap_stack  Run Address should be 0x2001FA00  (size 0x400 + 0x200 ==>0x600), end at 0x20020000. 

2. During debugging, I can use SP to view the stack pointer address. How can I view Heap address?

3. Stack area should be from  0x2001FC01 to 0x20020000; and heap area is from 0x2001FA00 to 0x2001FC00?

    If stack overflow, it will corrupt heap area data?

 

[Radosław]

Linker inly reserves define area for stack, in startup file initial stack value is set to end of RAM memory. 

 

Yes when stack wil overflow it will corrupt heap, bot only when full heap will be used,  

[TDK]

The heap starts at the "_end" symbol, which is at the end of the global memory in use. The heap includes all unused memory so it's typically quite a bit larger than the _Min_Heap_Size value.

[Pavel A.]

If you use the sysmem.c provided with the CubeIDE toolchain: the heap end address is the local variable __sbrk_heap_end in sysmem.c.

Per the "old good" naive memory layout, the stack goes from the end of the RAM down to the end of the heap. And the heap grows up until it hits the (current) SP. You may prefer a more robust layout where the stack size is fixed and located at the *bottom* of the RAM. Then overflowing the stack should cause exception. This is in line with allocation of fixed-size stacks in RTOSes. The heap will reside at the top of the RAM and can expand to the RAM end. Again, access above the end address should raise exception.

 

 

[New.Fish]

There is no sysmem.c file in my project, and I can't find the global variable __sbrk_heap_end as well. Is there other way to view the heap address during debug?

Stack, it start from the top @0x20020000, and decrease to bottom as function calls.

Heap, it start from "._user_heap_stack" (0x2000d160), and increase to top as call malloc(), right?

Once stack and heap goes to the same memory address, then crash will occur. 

 

[Ozone]

If you do not use malloc() and the like, you don't need heap memory.

Almost all my projects run fine with a heap size of zero.