advent of code 1.1 in BSD (osx) assembly

aoc1-1.asm

section .text

global mystart

int_to_string:
    add esi,9
    mov byte [esi],0

    mov ebx,10
.next:
    xor edx,edx
    div ebx
    add dl,'0'
    dec esi
    mov [esi],dl
    test eax,eax
    jnz .next
    mov eax,esi
    ret

mystart:
    mov dword [cnt], 0
    mov ecx, s1


loop1:
    mov dh, [ecx]
    cmp dh, 0
    jz done

    cmp dh, '('
    jz inc1

    dec dword [cnt]
    jmp cont

inc1:
    inc dword [cnt]


cont:
    inc ecx
    jmp loop1

done:
    mov eax, [cnt]
    mov esi, buff
    call int_to_string

    push dword 10
    push dword buff
    push dword 1

    mov eax, 0x4
    sub esp, 4
    int 0x80
    add esp, 16

    push dword 0
    mov eax, 0x1
    sub esp, 4
    int 0x80

section .data

    s1    db "(())", 0
    s1len equ $-s1
    cnt   dw 0
    buff  db '                 '

build

#!/bin/sh

# build
nasm -f macho main.asm

# link
ld -o hello -e mystart main.o