🚀 go-pugleaf

>Hello
>  
>I am trying to write a keyboard handler that will allow me 
>to know if any two keys are being pressed simultaneously.
>What are the ports that i should read?  And how do i interpret
>the this?
>
>-Chris Busch

  You can access the keyboard via port 0x60 ($60 for pascal people)

  The port returns the scan code of the key pressed. If the hi-bit
 is set, then the key was released.

  Pascal example:
   
     const
       hibit = $80;

     var
       spacebar,esc : boolean;
       scancode     : byte;
        .
        .
        .
     scancode := port[$60];
     if scancode=$34            { scan code for space = 57dec }
       then spacebar := true     
       else
         if scancode=$34+hibit
           then spacebar := false;   
     if scancode=1
       then esc := true 
       else
         if scancode=1+hibit
           then esc := false;

      The above code will return TRUE for SPACEBAR,ESC while it is
   pressed.  As soon as either key is released, SPACEBAR,ESC will
   be set to false.

      I suggest to override the keyboard interrupt at $9 and place 
   the coding there so you don't miss any keystrokes.
 
      Also for games, I don't call the old keyboard interrupt. I 
   don't overflow the key buffer. (I hate it when the keyboard beeps)

      This method works great in games.  I use it for shoot-em games
   that need to know when multiple keys are pressed and released.


 Send e-mail if you have any more questions.

  Scott Ramsay
  ramsays@access.digex.com