SECTION .text
global  _start

_start:
    mov     ecx, 0
loop:
    inc     ecx
    mov     eax, ecx
    call    iprint
    push    eax             ; push eax onto the stack to preserve it while we use the eax register in this function
    mov     eax, 0Ah        ; move 0Ah into eax - linebreak
    push    eax             ; push the linefeed onto the stack so we can get the address
    mov     eax, esp        ; move the address of the current stack pointer into eax for sprint
    call    stringPrint

    pop     eax             ; remove our linefeed character from the stack
    pop     eax             ; restore the original value of eax before our function was called

    cmp     ecx, 12         ; 12 is the hard-coded end of the loop
    jne     loop

    ;quit
    mov     ebx, 0
    mov     eax, 1
    int     80h
    ret


; -------SUBROUTINES-----------

iprint:
    push    eax                        ; counter of how many bytes we need to print in the endpush    eax             ; preserve eax on the stack to be restored after function runs
    push    ecx             ; preserve ecx on the stack to be restored after function runs
    push    edx             ; preserve edx on the stack to be restored after function runs
    push    esi             ; preserve esi on the stack to be restored after function runs
    mov     ecx, 0

divideLoop:
    inc     ecx             ; count each byte to print - number of characters
    mov     edx, 0          ; empty edx
    mov     esi, 10         ; mov 10 into esi
    idiv    esi             ; divide eax by esi
    add     edx, 48         ; convert edx to it's ascii representation - edx holds the remainder after a divide instruction
    push    edx             ; push edx (string representation of an intger) onto the stack
    cmp     eax, 0          ; can the integer be divided anymore?
    jnz     divideLoop      ; jump if not zero to the label divideLoop

printLoop:
    dec     ecx             ; count down each byte that we put on the stack
    mov     eax, esp        ; mov the stack pointer into eax for printing
    call    stringPrint          ; call our string print function
    pop     eax             ; remove last character from the stack to move esp forward
    cmp     ecx, 0          ; have we printed all bytes we pushed onto the stack?
    jnz     printLoop       ; jump is not zero to the label printLoop

    pop     esi             ; restore esi from the value we pushed onto the stack at the start
    pop     edx             ; restore edx from the value we pushed onto the stack at the start
    pop     ecx             ; restore ecx from the value we pushed onto the stack at the start
    pop     eax             ; restore eax from the value we pushed onto the stack at the start
    ret

slen:
    push    ebx
    mov     ebx, eax

nextchar:
    cmp     byte [eax], 0
    jz      finished
    inc     eax
    jmp     nextchar

finished:
    sub     eax, ebx
    pop     ebx
    ret

stringPrint:
    push    edx
    push    ecx
    push    ebx
    push    eax
    call    slen

    mov     edx, eax
    pop     eax

    mov     ecx, eax
    mov     ebx, 1
    mov     eax, 4
    int     80h

    pop     ebx
    pop     ecx
    pop     edx
    ret