defined subroutines$/$functions in ARM Assembly. Write an ARM Assembly program that will calculate the area of the following four plane shapes: a$)$ Triangle b$)$ Rectangle c$)$ Trapezoid d$)$ Square All number inputs are integers and all calculation results are provided in integer format. Any fractional calculations are to be truncated. The program must all meet the following requirements: $1.$ Each area calculation must be accessed as a subroutine$/$function $($ARM instruction BL$).2.$ The operands are passed to the function via the stack. Use the ARM pseudo instructions PUSH and POP. To ensure you are properly implementing the stack the registers used in your main routine to hold the operands must be different than those used in the subroutines. For example, your calling routine will push r$4$ and r$5$ on the stack but the called routine will pop into registers r$10$ and r$11.3.$ The function returns the results on the top of the stack. $4.$ Your program is to print a welcome$/$instruction messages to the user. $5.$ The user is prompted to enter the calculation type and the appropriate number of positive integers. $6.$ The program shall verify the user input is valid and report any entry errors. Ensure your program checks for non$-$integer inputs $($string$,$ floating$-$point, characters$).$ Invalid entries are reported and user prompted again to enter a valid input. $7.$ The program shall perform the calculation, display the results and report any overflow errors. Overflow is when the results do not fit into $32-$bit unsigned format. $8.$ Ask the user if they want to continue with another calculation or quit the program.