Code Composer Studio $-$ Assembly code $-$ MSP$430$

You are asked to write a subroutine $($let$\text{'}$s call it CFG$)$ with following contract

$($a$)$ Write the complete subroutine. Streamline your code as much as possible, minimize

number of lines of code and register use. You have an allowance of six lines of code

$($can be done with less$)$ and are not allowed $($and do not need$)$ to use any core registers

in R$4-$R$15.$ As an exception, please skip the comments this time to make grading

in Carmen easier.

$($b$)$ What is the largest value of $n$ that this subroutine can handle correctly $($i$.$e$.,$

return a correct output$)?$