We want to write an ARM assembly program that calculates the mean absolute difference $$ of two arrays $x$ and $y$ of $N32-$bit numbers stored in memory:

$=\frac{1}{N}{\displaystyle \underset{i=1}{\overset{N}{}}}|x_i-y_i|$

The ARM assembly program shall use a subroutine mean where the parameters are passed using the stack.

a$)$ Write an ARM subroutine mean that calculates the mean absolute difference $$ by reading the two array addresses and their size from the stack and returning the result on the stack.

b$)$ Write the main ARM program that reads from memory the size $N$ and the two arrays $x$ and $y$ of $N32-$ bit numbers, then calculates the mean absolute difference by calling the subroutine mean, and finally stores the result sigma in memory.