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From: warwick@cs.uq.oz.au (Warwick Allison)
Newsgroups: comp.sys.atari.st.tech
Subject: Re: Assembly joystick routines WANTED (Please)
Message-ID: <1741@uqcspe.cs.uq.oz.au>
Date: 3 Jun 91 23:23:11 GMT
References: <42873@cup.portal.com> <10759@castle.ed.ac.uk>
Sender: news@cs.uq.oz.au
Reply-To: warwick@cs.uq.oz.au
Lines: 116

>>     I am having a terrible time reading the joystick port (1 and 2) from 
>>assembly language. If you have an assembly routine that will do this, could yo
>>please post it or send it to me?
>>
> I would also like to see this posted as Atari ST internals doesn't make
>this clear enough for me..

Okay, I'll post my code.  Note that I think this WORKS (on tos 1.0, and 1.4 so far)
but I think it may be wrong (because I am assuming "a0" is the input parameter,
whereas I expect it would be on the stack).

This is my code:

First, the packet handler:

JoyDo:
    movem.l d0/a1,-(sp)
    move.l  #Stick,a1     ; Location of the place you want to
    move.w  1(a0),d0      ; store data (it is "byte Stick[2]")
    cmp.b   #$FF,(a0)     ; (or VAR Stick:ARRAY [0..1] OF CHAR)
    beq     Joy1
    lsr.w   #8,d0
    add.l   #1,a1
Joy1:
    move.b  d0,(a1)
    movem.l (sp)+,d0/a1
    rts

That isn't my actual code - I decode the directions and trigger - but it shows
what you want.

Now the rest (which you can probably work out already)... It's in Modula-2,
so anyone who knows Pascal can work it out.


TYPE KeyVectors=POINTER TO
         RECORD
            midivec,vkbderr,vmierr,statvec,
            mousevec,clockvec,joyvec:ADDRESS
         END;

VAR OldJoy:ADDRESS;

PROCEDURE InitJoysticks;

VAR KV:KeyVectors;
    Cmd:CHAR;

BEGIN
    Cmd:=024C; (* 20 decimal, 14 hex *)
    ikbdws(ADR(Cmd),0)
    KV:=kbdvbase();
    OldJoy:=KV^.joyvec;
    KV^.joyvec:=ADDRESS(JoyDo);
END InitJoysticks;

PROCEDURE TermJoysticks;

VAR KV:KeyVectors;
    Cmd:CHAR;

BEGIN
    Cmd:=010C; (* 8 decimal/hex *)
    ikbdws(ADR(Cmd),0);
    KV:=kbdvbase();
    KV^.joyvec:=OldJoy;
END TermJoysticks;


Finally, I appologise if this is ugly or incorrect, all I have seen of this
module for a while is:


DEFINITION MODULE Joysticks;

(* Supplies access to the two joystick ports *)

TYPE	JoystickDirection=(none,up,down,updown,
				left,upleft,downleft,updownleft,
				right,upright,downright,updownright,
				leftright,upleftright,downleftright,
				updownleftright);

	JoystickRecord=	RECORD
				Up,Down,Left,Right,Trigger:BOOLEAN;
			END;

(* A variety of formats... *)

VAR	Joystick:ARRAY [0..1] OF JoystickRecord;
	Stick:ARRAY [0..1] OF JoystickDirection;
	Trig:ARRAY [0..1] OF BOOLEAN;

	XStick:ARRAY JoystickDirection OF INTEGER;
	YStick:ARRAY JoystickDirection OF INTEGER;

PROCEDURE InitJoysticks;
(* Enables both joysticks, disables mouse movement *)

PROCEDURE TermJoysticks;
(* Restores normal mouse action, disables joysticks *)

(* InitJoysticks is automatically done at initialisation
   TermJoysticks is automatically done upon termination *)

END Joysticks.


Long live M2,
Ciao,
Warwick.
--
  _-_|\       warwick@cs.uq.oz.au
 /     *  <-- Computer Science Department,
 \_.-._/      University of Queensland,
      v       Brisbane, AUSTRALIA.