title: Segmentation Fault: int 80h
body: <p>Recently I have been learning NASM x86 Assembly. And in writing my code, whenever I use <code>int 21h</code> or <code>int 80h</code> or any interrupt for that matter it returns a segmentation fault. The entire program is:</p>
  
  <pre><code>section .data
      msg: dw 'Hello World!', 10
  section .text
      global _main
  
  _main:
      mov eax, 4
      mov ebx, 1
      mov ecx, msg
      int 80h
  </code></pre>
  
  <p>Any help or tips on where I can learn more about NASM is highly, higjly appreciated.</p>