CORTEX-M4 Core Registers

CORTEX-M4 Core Registers

Goal: Visualizing what happens to the CORTEX-M4 core registers after reset


Here's what happens after the processor is reset:

• General-purpose registers has unknown values in them
• Stack pointer register are loaded with th e value of the  Initial SP value  register located at 0x0000 (Vector Table)
• Link Regis ter'll has 0xFFFFFFFF
• program counter was loaded with the value of the  Reset  regis ter located at 0x0004  (Vector Table)
• in the case of stm32f4,  Reset  regi Ster contains the address of the  Reset_handler  which is defined in  startup_ Stm32f40xx.s
• reset_handler  performs microcontroller System Setup, configures the system clock, eventually branches to __ main  (entry point of a program)  in The C library. 
• Vector Table is mapped to address 0 at Reset (can being relocated in this range:0x00000080 -0x3fffff80)

Summary of registers and their roles in the procedure Call Standard (AAPCS).

CORTEX-M4 Core Registers