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/* Demonstration of reading joy stick postition
   uses BIOS function for reading the stick;

*/

#include <stdio.h>
#include <dos.h>
#include <bios.h>
#include <conio.h>
#include "cursor.c"

typedef struct {
	int sw1,sw2;
	int x,y;
	int cenx,ceny;
	} joy_stick;

joy_stick joy;

#define keypressed (bioskey(1) != 0)
#define kb_clear() while keypressed bioskey(0);

union REGS inregs,outregs;
struct SREGS segregs;


void GotoXY(int x,int y)
{
	union REGS r;
/* Set XY position */
	r.h.ah = 2;
	r.h.bh = 0;            /* Assume Video Page 0 */
	r.h.dh = (char) y;
	r.h.dl = (char) x;
	int86(16,&r,&r);
}

disp_stick(int line)
{
	GotoXY(0,line);
	printf("sw1 %d sw2 %d",joy.sw1,joy.sw2);
	GotoXY(0,line+1);
	printf("x %6d y %6d",joy.x,joy.y);
}

int read_buttons()
{
	inregs.h.ah = 0x84;
	inregs.x.dx = 0;
	int86x(0x15,&inregs,&outregs,&segregs);
	joy.sw1 = ((outregs.h.al >> 4) & 1) == 0;
	joy.sw2 = ((outregs.h.al >> 5) & 1) == 0;
	return (int)outregs.h.al;
}

read_stick()
{
	int jx,jy;

	inregs.h.ah = 0x84;
	inregs.x.dx = 1;
	int86x(0x15,&inregs,&outregs,&segregs);
	jx = outregs.x.ax;
	jy = outregs.x.bx;
	joy.x = jx-joy.cenx;
	joy.y = jy-joy.ceny;
}


center_stick()
{
	int init_swa,init_swb,swa,swb;
	int c,retval;

	printf("Joystick testing program  BIOS version\n");
	printf("--------------------------------------\n\n");
	printf("Center joystick and press fire\n");
	kb_clear();
	c = read_buttons();
	init_swa = c & 0x30;
	init_swb = c & 0xc0;
	do {
	   c = read_buttons();
	   swa = c & 0x30;
	   swb = c & 0xc0;
	} while ((swa == init_swa) && (swb == init_swb));
	if (swa != init_swa) {
	   printf("Joystick 1 selected\n");
	   retval = 1;
	} else if (swb != init_swb) {
	   printf("Joystick 2 selected\n");
	   retval = 2;
	}

   joy.cenx = joy.ceny = 0;
   read_stick(joy);
   joy.cenx = joy.x;
   joy.ceny = joy.y;
}

main()
{
   int k;

   clrscr();
   HideCur();
   center_stick();
   while (!keypressed) {
		read_buttons();
		read_stick();
		disp_stick(6);
   }
   clrscr();
   ShowCur();
}
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