Question

Consider the following array with the contents given:
5 5 5 5 5 5 5 5 5 5

Do the the following:
a) Write an assembly code using index addressing to add all the elements in the array and store the result in a memory location 'RESULT'. consider each of the element is of WORD size

Answer 1

Here is an assembly code using index addressing to add all the elements in the array and store the result in a memory location 'RESULT':

```assembly
section .data
array DW 5, 5, 5, 5, 5, 5, 5, 5, 5, 5
RESULT DW 0

section .text
global _start

_start:
mov ecx, 10 ; Initialize loop counter to 10
mov esi, 0 ; Initialize array index
mov ax, [array + esi * 2] ; Load first element of the array into ax register

loop_start:
add ax, [array + esi * 2] ; Add the current element of the array to ax
add esi, 1 ; Increment array index by 1
loop loop_start ; Repeat until loop counter becomes zero

mov [RESULT], ax ; Store the result in memory location RESULT

exit:
mov eax, 1 ; Exit system call
xor ebx, ebx ; Exit status 0
int 0x80 ; Perform the system call
```

In this code, the `array` is stored in the `.data` section with the given elements. The `RESULT` is also declared in the `.data` section to store the final result.

In the `_start` section, the loop counter `ecx` is initialized to 10 (as there are 10 elements in the array). The array index `esi` is set to 0 initially. The first element of the array is loaded into the `ax` register using index addressing (`[array + esi * 2]`) as each element is of WORD size (2 bytes).

Then, a loop (`loop_start`) is started. Inside the loop, the current element of the array is added to the `ax` register using index addressing. The `esi` is then incremented by 1 to move to the next element. The loop continues until the loop counter `ecx` becomes zero.

After the loop, the final result in the `ax` register is stored in the memory location `RESULT` using the `mov` instruction.

Finally, the code exits using a system call, ensuring the `RESULT` is stored in the memory location specified.