In order to comply with the application binary interface (ABI) of the CPU, it is required to assign space in memory for the execution stack. This can be done in different ways, but usually it is preferable to mark the end of the stack space in the linker script, and associate the stack space to a specific area in RAM not in use by any section.
The address obtained through the END_STACK symbol, exported by the linker script, points to the end of an unused area in RAM. As mentioned earlier, its value must be stored at the beginning of the vector table, at address 0 in our case, just before the IV. The address of the end of the stack has to be constant, and cannot be calculated at runtime, because the IV content is stored ...
