2-10-1. Operation Mode and Stack Pointer (1)

Arm^® Cortex^®-M3 has two privileged levels (Privilege/Non-privilege) and two operation modes (Thread/Handler).
For embedded usage, a basic configuration with only privileged level or a configuration to switch between Privilege and Non-privilege can be selected.
At the privileged/non-privileged level, by switching between the main stack (MSP) and process stack (PSP) assigned to register R13, the stack area can be separated and managed by processing functions such as the OS kernel and user routines.