OSDev.org

Posted: **Sat Apr 29, 2006 9:36 pm**

I am rewriting my keyboard driver (again) and I have ran into this problem: I have a loop in my getchar() function that waits until a key is pressed:

Code: Select all

   while(keypressed!=1)
   {
        __asm__ __volatile__("hlt");
   }

The problem is that this just keeps looping forever. However, for some reason, this following code works perfectly, but it fills the screen with "2"s:

Code: Select all

   while(keypressed!=1)
   {
        __asm__ __volatile__("hlt");
      puts("2");
   }

I can't get it to work unless I print the 2s.... Why is this?

Thanks,

-Stephen

Posted: **Sat Apr 29, 2006 11:01 pm**

This is just a wild guess, but did you declare the keypressed variable to be volatile?

Posted: **Sat Apr 29, 2006 11:07 pm**

Whoops... I accidentally just declared it an int.

Thanks for the quick reply!

-Stephen

OSDev.org

Strange problem with loop

Strange problem with loop

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Re:Strange problem with loop