section .data

MsgBalanced: db "OK", 10
MsgBalancedLen: equ 3

MsgUnbalanced: db "NOT OK", 10
MsgUnbalancedLen: equ 7

MsgBadInput: db "BAD INPUT", 10
MsgBadInputLen: equ 10

Open: equ '['
Closed: equ ']'

section .text

BalancedBrackets:

  xor rcx, rcx
  mov rsi, rdi
  cld

  processBracket:
    lodsb
    cmp al, 0
    je determineBalance

    cmp al, Open
    je processOpenBracket

    cmp al, Closed
    je processClosedBracket

    mov rsi, MsgBadInput
    mov rdx, MsgBadInputLen
    jmp displayResult

    processOpenBracket:
      add rcx, 1
      jmp processBracket

    processClosedBracket:
      cmp rcx, 0
      je unbalanced

      sub rcx, 1
      jmp processBracket


  determineBalance:
    cmp rcx, 0
    jne unbalanced

    mov rsi, MsgBalanced
    mov rdx, MsgBalancedLen
    jmp displayResult

  unbalanced:
    mov rsi, MsgUnbalanced
    mov rdx, MsgUnbalancedLen

  displayResult:
    mov rax, 1
    mov rdi, 1
    syscall
    ret