Checking for two-digit numbers in assembly , and then summing them

Question

To be fair I'm completely lost and this code is probably completely wrong, but I wanted to ask how do I create a loop that checks for two digit numbers in my array in assembly.[enter image description here][1]

[1]: https://i.sstatic.net/BZ2BM.png /// Edit , complety rewrote the code now it works thank youu everyone for the help <3

Answer 1

As far as I understood, you have an array with numbers in it. And you want to find the sum of 2-digit numbers. To do that, first, let us define an array and a sum variable. Putting a 0xFFFF at the end of our list will help us locate the end of the list.

arr: dd 15, 16, 9, 8, 0xFFFFFFFF
sum: dd 0x00000000

Now we need to iterate over the array and find two-digit numbers:

start:
    push ebx
    mov edx, arr ; get the address of the array
    xor ecx, ecx
.loop:
    mov eax, dword [edx] ; get the nth word into eax
    cmp eax, 0xFFFFFFFF ; check if we are at the end of list
    je endLoop ; if we are end the loop
    add edx, 4 ; add 2 to the pointer to get the next word.
    
    cmp eax, 9 ; check if the nth word is 1 digit
    jng .loop ; if it is 1 digit just loop
    cmp eax, 99 ; check if it is 3 digits
    jg .loop ; loop if it is

    add ecx, eax ; we have the two digit number, add it to sum
    jmp .loop ; and loop

endLoop:
    mov dword [sum], ecx
    pop ebx
    ret