Your task is to write assembly code that adds all the numbers in a given word array $($i$.$e$.,$ array

of $16-$bit numbers$).$ The array has $60$ elements. Each of these elements is a signed integer

value between $-100$ and $+100($inclusive$).$ You will use indexed mode to access the elements in

the array and find the sum of these $60$ elements in R$5.$

This is a great point to stop and write such a program yourself. Define an array in RAM using

assembler directives, you can fill it with signed random integers taking values in the range $,$

$100].$ No need to create a variable for the sum, you will compute the sum in R$5.$

Once you have your code ready, you can continue to the next page.

ECE $2560$ Intro to Microcontroller$-$Based Systems

Autumn $2024$

Here is one attempt at the code that does the given task. You can see that the code is not even

compiling due to blanks in lines $38,39,$ and $40.$

Main loop here

$33$

$34$

clr$.$le R$4$

$6$ add$\_$next:

$30$;

$\backslash$

$\backslash$

$37$

$38$

e$.39$

cmp$.\backslash$ ## R$4$

$40$

jlo add$\_$next

done:

$43$

nop

Can you fill in the blanks in lines $38$ and $39$ so that the code adds all $60$ numbers in the array

$($and no other number$).$

$($a$)$ What is the correct instruction for line $38?$ Remember to enter the complete mnemonic

including the byte$/$word indicator $.$b or $.$w

Next, we need to fill the blanks in line $39.$ Can you identify the value$($s$).$ If there is only one

correct value enter the same number in part $($b$)$ and $($c$).$

$($b$)$ What is the smallest value that works in line $39?$ Enter a decimal number.

$($c$)$ What is the largest value that works in line $39?$ Enter a decimal number.

$($d$)$ Is there another correct choice of instruction that works in line $40?$ Correct means that

the instruction would deliver correct results for any scenario where we are processing

$($here adding$)$ all numbers in an array $($here $60$ elements$).$