• State Accepted Answer
  • +1 person also asked this people also asked this
  • Locked Locked
  • Replies 1 reply
  • Subscribers 351 subscribers
  • Views 10697 views
  • Users 0 members are here
2025 survey

We are running a survey to help us improve the experience for all of our members. If you see the survey appear, please take the time to tell us about your experience if you can.

Options
How was your experience today?
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

Beginner question: stack pointer initialization

Michele Viti

Hi,

I'm pretty new to ARM processor and STM32 microcontroller, so my question is very basic.

In the startup file for a SW4STM32 project (eg startup_stm32f446xx.s) the stack pointer is set in Reset_Handler with the line

ldr  sp, =_estack     /* set stack pointer */

 

why is this needed? I mean as far as I know the ARM Cortex-M is fetching automatically the value of the stack pointer as first step during the booting sequence. Why has it to be done a second time via software? I looks like it is initialized twice to the same value (_estack) since the vector table has the form:

 

.word _estack

.word Reset_Handler

.

.

.

0