Code this in ARM

Use the following algorithm to calculate the nth number in the fibonacci sequence. Inputs will be from $1$ to $10.$ Input of $1$ should return $0,$ input of $2$ should return $1,$ input of $3$ should return $1,$ input of $4$ should return $2,$ input of $5$ should return $3,$ and so on$.$

procedure fib$($argument: n$)$

return fib$($n$-2)+$ fib$($n$-1)$

You must use this argument. Yes, I know every caution you've been given to NEVER use such an algorithm. This is an exercise in understanding recursion and calling procedures in assembly language.

If you use a loop or an equivalent to a case$/$switch table, your score on the assignment will be $20/100.$

Requirements and Specifications

Your input cannot be stored as a global variable at any point. This means you cannot store it at a data section address, even when accepting them from scanf; they must be returned from scanf on the stack.

X$19-$X$27$ are global variables. You may not use X$19-$X$27$ in your recursive function. If you want, you may use X$19-$X$27$ in your main function. You can use any registers you want to in your main function.

A recursion procedure requires:

Allocate stack space

Save the return address and argument on the stack

Recursively call procedure with BL

Unwind the stack by restoring the return address and arguments and deallocating stack memory

If the code is not recursive, i$.$e$.$ uses a loop or a the equivalent of a case$/$switch table, your score will be $20/100.$

Hints and Warnings

You must put the local values and return address on the stack before any bl call, and restore the argument and the return address after the bl call.

Skeleton Code:

$.$section $.$data

input$\_$prompt : $.$asciz "Please enter a number betwen $1$ and $10$

$"$

input$\_$spec : $.$asciz $"\%$d$"$

fib : $.$asciz $"\%$d

$"$

oob$\_$mess : $.$asciz "Input is out of bounds

$"$

$.$section $.$text

$.$global main

main:

# branch to this label on program completion

exit:

mov x$0,0$

mov x$8,93$

svc $0$

ret