title: Why does PC halt when i try to hook INT 13h from my bootloader?
body: <p>My computer halts when i write my software onto MBR. My software is for hook INT 13h and execute some code when INT 13h is executed. I already try with too many ISRs for INT 13h but unsuccessfully. Here is my example source:</p>
  
  <pre><code>cli
  cs
  mov si,[4Ch]
  cs
  mov di,[4Eh]
  cs
  mov [180h],cx
  cs
  mov [182h],dx
  mov si,0h
  mov di,2000h
  cs
  mov [4Ch],si
  cs
  mov [4Eh],di
  sti
  mov si,2000h
  mov di,0
  mov ds,di
  mov es,si
  mov si,7C6DH
  mov di,0
  mov cx,codelastbyte-payload
  cld     
  repz
  movsb
  
  mov ax,201h
  push cs
  pop es
  mov bx,7c00h
  mov cx,7
  mov dx,80h
  int 60h
  jmp 0:7C00h
  
  payload:           ;NEW INT13H
  sti
  INT 60H
  iret
  
  codelastbyte:
  </code></pre>
  
  <p>What is wrong?</p>