Path: utzoo!attcan!uunet!husc6!bloom-beacon!apple!claris!ames!oliveb!amiga!bart
From: bart@amiga.UUCP (Barry A. Whitebook)
Newsgroups: comp.sys.amiga.tech
Subject: Proportional joysticks
Keywords: interrupt handler
Message-ID: <3086@amiga.UUCP>
Date: 5 Nov 88 20:19:09 GMT
Reply-To: bart@amiga.UUCP (Barry A. Whitebook)
Organization: Commodore-Amiga Inc, Los Gatos CA
Lines: 127

[eat this line -- please]

this is amiga!bart. as this subject keeps resurfacing in various venues i'm
going to post a some code to read prop joysticks using interrupt handlers.

/******************************************************************************
*	$Header: propjoy.c,v 34.1 85/11/24 17:59:44 bart Exp $
******************************************************************************/

#include <exec/types.h>
#include <exec/nodes.h>
#include <exec/execbase.h>
#include <exec/execname.h>
#include <graphics/gfxbase.h>
#include <graphics/graphint.h>
#include <hardware/cia.h>
#include <hardware/custom.h>
#include <hardware/intbits.h>
#include <resources/potgo.h>
extern struct Custom custom;

#define V1_POINT_2	33
#define NUM_SERVERS	2
#define MAX_COUNT	(UWORD)~1		
#define POTGO		&custom.potgo
#define POT0DAT		&custom.pot0dat
#define POT1DAT		&custom.pot1dat
#define HIGHINTPRI 127L 	
#define LOWINTPRI -127L 	
#define START_B		0	
#define DATRX_B		8	
#define DATRY_B		10
#define DATLX_B		12	
#define DATLY_B		14
#define START_F		(1L << START_B)
#define DATRX_F		(1L << DATRX_B)
#define DATRY_F		(1L << DATRY_B)	
#define DATLX_F		(1L << DATLX_B)
#define DATLY_F		(1L << DATLY_B)	
#define RPOTX		(START_F | DATRX_F) 
#define RPOTY		(START_F | DATRY_F) 
#define RPOTXY		(START_F | DATRX_F | DATRY_F) 
#define LPOTX		(START_F | DATLX_F) 
#define LPOTY		(START_F | DATLY_F) 
#define LPOTXY		(START_F | DATLX_F | DATLY_F) 

struct ExecBase *ExecBase = NULL;
struct GfxBase *GfxBase = NULL;
struct PotgoBase *PotgoBase = NULL;

UWORD oldbits = NULL;
UWORD potbits = NULL;
ULONG potdat = NULL;

struct Isrvstr server[NUM_SERVERS] = {NULL};

first_server(i) 
int i; 
{ 
	potdat = *(ULONG *)POT0DAT;
	WritePotgo(oldbits,((~1)<<8)|oldbits);
	return(NULL);
}

second_server(i)
int i;
{
	WritePotgo(potbits,((~1)<<8)|potbits);
	return(NULL);
}

use(data)
ULONG data;
{
	printf("use: data == %08lx\n",data);
}

main()
{
	LONG error = FALSE;
	struct Isrvstr *iserver[NUM_SERVERS];
	LONG i;

	server[0].is_Node.ln_Pri = HIGHINTPRI;	
	server[1].is_Node.ln_Pri = LOWINTPRI;	
	iserver[0] = &server[0];
	iserver[1] = &server[1];

	if((ExecBase = (struct ExecBase *)
	    OpenLibrary(EXECNAME,V1_POINT_2)) != NULL)
	{
		if((GfxBase = (struct GfxBase *)
		    OpenLibrary("graphics.library",V1_POINT_2)) != NULL)
		{
			if((PotgoBase = 
			    OpenResource(POTGONAME,V1_POINT_2)) != NULL)
			{
				oldbits = ~(AllocPotBits(~1));
				FreePotBits(~oldbits);
				potbits = AllocPotBits(START_F);
				Forbid();	
				iserver,first_server,0);
				AddTOF(iserver[0],first_server,0);
				iserver,second_server,1);
				AddTOF(iserver[1],second_server,1);
				Permit();
				for(i=0; i < MAX_COUNT; i++)
				{
					WaitTOF();
					use(propjoy);
				}
				Forbid();	
				for(i=0; i < NUM_SERVERS; i++)
				{
					RemTOF(iserver[i]);
				}
				Permit();
				FreePotBits(potbits);
				CloseLibrary(GfxBase);
			}
			else { error = TRUE; }
		}
		else { error = TRUE; }
		CloseLibrary(ExecBase);
	} else { error = TRUE; }
	exit(error);
}