$6\mathrm{.}10$ Problem $6$c: Elevator

Create a new Platform.IO project called Lab$6$c$.$ Your project should include the startup.s$,$

ECE$251\_$asm$\_$util.s and platformio.ini files from the Lab$6$ zip file. Create a new main.s file

with the program you will write

Consider a $9-$story building with a basement. The first floor is given the number $1,$ the second

is given the number $2$ and so on$.$ The basement is given the number $0.$ You will write a program

to simulate an elevator operated throughout the whole building. Write the following

subroutines that will work with the main program,

a$)$ DELAY: generates a software delay of $1$ second.

b$)$ OPEN: displays a $$Door open$$ message on the screen after a delay of $1$ second. A

working version of this code is supplied for your use, if you like on Canvas.

c$)$ CLOSE: displays a $$Door close$$ message on the screen after a delay of $1$ second.

d$)$ UP: performs the following procedure:

i$.$ Displays a $$Going UP$$ message on the screen.

ii$.$ Goes up one floor at a time $(1$ second delay between each floor$),$ until the elevator

reaches the destination.

iii. At each floor, prints that number $($current floor number$)$ plus a space on the screen.

iv$.$ After the elevator reaches the destination floor, stores this number as the current

floor number in memory.

e$)$ DOWN: performs the following procedure:

i$.$ Displays a $$Going DOWN$$ message on the screen.

ii$.$ Goes down one floor at a time $(1$ second delay between each floor$),$ until the

elevator reaches the destination.Lab$6$ FA$24$ Subroutines and the Stack

$-7-$

iii. At each floor, prints that number $($current floor number$)$ on the screen.

iv$.$ After the elevator reaches the destination floor, stores this number as the current

floor number in memory.

f$)$ STAY: displays a $$Same floor$$ message on the screen after a delay of $1$ second.

Following is the pseudo code you can use for your main program,

$1.$ Initialize the elevator at floor #$1($memory location containing the present location of

the elevator$).$

$2.$ Call the $$OPEN$$ subroutine.

$3.$ Wait for the input from the user $(0-9).$

$4.$ Call the $$CLOSE$$ subroutine.

$5.$ Compare the number input with the present floor number.

$6.$ If the number input is greater than the present floor number, call the $$UP$$ subroutine.

Then jump to step $9.$

$7.$ If the number input is less than the present floor number, call the $$DOWN$$ subroutine.

Then jump to step $9.$

$8.$ If the number input is equal to the present floor number, call the $$STAY$$ subroutine.

$9.$ Jump back to step $2.$

Your output should look something like this:

Show the working program to TA$.$