The core register R13 of an ARM Cortex-M4 processor is used as a. Program counter. b. Link register. c. Stack pointer. There are two stacks (main stack and process stack) implemented in an ARM Cortex-M4 processor. When the processor is in handler mode, the stack used is a. main stack b. process stack. c. either main stack or process stack. Find the solutions for the following problems The prototype of a C-callable assembly function in a C program is extern int norm_sq_asm(int *p, int n); Based on the rule of the ARM Architecture Call Standard, find which core registers are used to pass the pointer p and the integer n to the assembly function and which register used for return value of the assembly function