Problem in Loop

flat assembler
Message board for the users of flat assembler.

Index > Windows > Problem in Loop

Author

Thread

Ianis

Joined: 06 Jan 2011
Posts: 10

Ianis

Code:

format PE GUI 4.0
entry EntryPoint

EntryPoint:      
    xor eax, eax
        xor ebx, ebx
        mov ecx, 0FFFFh
     bloop:
          mov al, 7Ah
         sub al, 80h
         mov bx, 0FFh
                idiv bx
     loop bloop
  ret

Hello I would like to know why the code doesn't loop and get stuck on idiv bx.
Thank you.

17 Mar 2012, 19:40

cod3b453

Joined: 25 Aug 2004
Posts: 618

cod3b453

The division is applied to dx:ax, so if dx:ax/bx cannot fit inside ax #DE exception will occur; to fix this zero dx before each idiv (after idiv the remainder is put in dx)

17 Mar 2012, 20:48

Ianis

Joined: 06 Jan 2011
Posts: 10

Ianis

Thank you a lot cod3b453.
I didn't know it works like that.

18 Mar 2012, 15:43

< Last Thread | Next Thread >

Forum Rules:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum