Write a complete program that includes a subroutine called GCD to compute the greatest common divisor $($GCD$)$ of two numbers a and b$.$

The subroutine will accept two inputs $a,b$ and return the result on the RTS$.$ Use the following algorithm to compute the GCD$($a$,$b$).$

Algorithm $1$: GCD Algorithm

Input : $a,b$ where $a,b>0$

Output: $GCD(a,b)$

$1$ while $ab$ do

$2$ while $a>b$ do

$3,$clarra$-b$

$4,$alarrc

$5$ end

$6$ while $b>a$ do

$7,$clarrb$-a$

$8,$blarrc

$9$ end

$10$ end

$11$ return $a$

Include a main program to test your subroutine. Try testing with values $a=66,b=12($store these using labels with the same name$).$ You can put

your test values in memory locations given by labels a$,$ b$.$ When the subroutine returns, your program should extract the result and store it at

the memory location given by label result. You may use the following template for your program.

;Implements a subroutine to compute GCD

$.$orig $3000$

main

LD R$6,$ stackbase

;set up RTS

; put your code for the mainline here

HALT

a $.$ fill $66$ ;change a and $b$ to test your program with different values

b $.$fill $12$

result $.$blkw $1$

stackbase $.$fill ex $40$

GCD