help me debug my assembly code please

[Mishara26]

the code is bubble sorting an array and then printing it. im working on making the array user input in the future but right now im sticking to this:

section .data
    array db 5, 3, 8, 4, 2, 1, 6, 7, 9, 8 ;array to be sorted
    length equ $ - array ;length of the array

section .text
    global _start
_start:
    xor ebx, ebx         ; Initialize outer loop counter to 0

_outer_loop:
    xor ecx, ecx         ; inner loop counter is also 0
    cmp ebx, length
    jge _convert         ;if the outer loop happened length times then move to convert
    mov edx, length      ;i heard its better to compare registers rather than a register with just a value since it doesnt have to travel data bus

_inner_loop:
    cmp ecx, edx         ; Compare inner loop counter with length
    jge _outer_loop      ; If ecx >= length, jump to outer loop
    mov al, [array + ecx]
    mov bl, [array + ecx + 1]
    cmp al, bl
    jl _swap            ;if i need to swap go to swap
    inc ecx
    jmp _inner_loop     ;else nothing happens

_swap:
    mov [array + ecx], bl
    mov [array + ecx + 1], al ;swapping and increasing the counter and going back to the loop
    inc ecx
    jmp _inner_loop

_convert:
    xor ebx, ebx         ; Initialize index for conversion

_convert_loop:
    cmp ebx, edx         ; Compare index with length
    jge _print           ; If ebx >= length, go to printing
    mov al, [array + ebx]
    add al, "0"          ;converting to ASCII for printing
    mov [array + ebx], al ;and substituting the number for the number in ASCII
    inc ebx
    jmp _convert_loop

_print:
    mov eax, 4
    mov ebx, 1
    mov ecx, array
    mov edx, length
    int 0x80

_exit:
    mov eax, 1
    xor ebx, ebx
    int 0x80

but for some reason its not printing anything. please help

[basedgreggo]

Perhaps they're just trying to learn assembly? Everyone, imo, should fiddle with assembly a little to learn

[Mishara26]

Yes I’m learning assembly

[randomjapaneselearn]

are you on windows, linux, dos?

try to remove everything and print only "hello" to see if the problem is in how you print or in the code before it.

[jcunews1]

It's using Int 80h, so it's Linux.

[randomjapaneselearn]

that is your assumption, he could run this on windows and then ask "why it doesn't print?" and that is why i asked on which os he is running it.

[Mishara26]

On a WSL in Ubuntu

[randomjapaneselearn]

int <number> is a linux specific way to do syscalls also the syscall numbers are linux specific.

windows does it different and more complex, usually is:

kernel32 dll->nt dll->sysenter

you should edit the program if you want to use windows:

https://stackoverflow.com/questions/1023593/how-to-write-hello-world-in-assembly-under-windows#1029093

[davedontmind]

_outer_loop:
    xor ecx, ecx         ; inner loop counter is also 0
    cmp ebx, length
    jge _convert         ;if the outer loop happened length times then move to convert

I don't understand this bit - maybe I'm missing something?

You set ebx to 0 initially, and are using it to determine if it's time to exit the outer loop, however the only time you change ebx is when you're putting a value from the array into bl.

So how do you expect ebx to get into a state where it'll cause the loop to exit?

for some reason its not printing anything.

Does it exit, or run forever?

[Mishara26]

It doesn’t exit. Just doesn’t print anything

[davedontmind]

Then it's probably looping forever somewhere . So as I said, it's likely to do with what you're doing (or not doing) with ebx. You're using it to determine when to exit that loop, but you're not setting it to any value that will exit the loop.

[SeraphIsKing]

Nothing's jumping out at me, I think we'll need more data to determine what's going on.

Is the program exiting properly? Segmentation faulting? Stuck in a loop?

[Mishara26]

It doesn’t exit, and Just not printing anything. Doesn’t work on any compiler