Path: utzoo!yunexus!maccs!cs3b3aj
From: cs3b3aj@maccs.McMaster.CA (Stephen M. Dunn)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Determining Keyboard Codes
Message-ID: <2269@maccs.McMaster.CA>
Date: 29 Mar 89 20:21:09 GMT
Article-I.D.: maccs.2269
References: <1244@naucse.UUCP>
Reply-To: cs3b3aj@maccs.UUCP (Stephen M. Dunn)
Organization: McMaster U., Hamilton, Ont., Can.
Lines: 25


   There are (as far as I know) two ways of finding out what keys have been
pressed if you are writing in assembly language or a language which can do
software interrupts; if you're trying to modify existing software, you're
probably out of luck.  Anyway, here goes.

   One method is to get keystrokes with INT 16h function 0.  This returns the
ASCII code in AL and the scan code in AH; these scan codes are the same on
all PC-compatible keyboards.  (Note that this function waits for a key to be
pressed; use function 1 to check for key presses).

   The other method is to replace the machine's keyboard driver with one of
your own.  This involves intercepting int 9, which the keyboard generates
whenever a key is pressed or released.  However, this gets kinda messy and
will cause problems if you have another program in memory doing the same
thing (e.g. Sidekick).  If you want more info on this, you can probably
find some in the IBM PC Technical Reference Manual (or whatever they
call it).

Hope this helps.
-- 
======================================================================
! Stephen M. Dunn, cs3b3aj@maccs.McMaster.CA ! DISCLAIMER:           !
! I always wanted to be a lumberjack! - M.P. ! I'm only an undergrad !
======================================================================