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/*
** JOYSTICK.H
**
** Joystick support functions
**
** Public domain demo by Bob Stout
*/
typedef enum {ERROR = -1, FALSE, TRUE} LOGICAL;
#define BOOL(x) (!(!(x)))
#define SUCCESS 0
struct joystick {
LOGICAL switch_0;
LOGICAL switch_1;
LOGICAL switch_2;
LOGICAL switch_3;
int pos_Ax;
int pos_Ay;
int pos_Bx;
int pos_By;
};
LOGICAL read_joystick(void);
/*
** JOYSTICK.C
**
** Joystick support functions
**
** Public domain demo by Bob Stout
*/
#include <dos.h>
#include "joystick.h"
struct joystick JoyStick;
/*
** read_joystick()
**
** returns SUCCESS or ERROR
**
** fills in global JoyStick structure
*/
LOGICAL read_joystick(void)
{
union REGS regs;
regs.h.ah = 0x84; /* Read the switches */
regs.x.dx = 0;
int86(0x15, ®s, ®s);
if (regs.x.cflag)
return ERROR;
JoyStick.switch_0 = BOOL(regs.h.al & 0x10);
JoyStick.switch_1 = BOOL(regs.h.al & 0x20);
JoyStick.switch_2 = BOOL(regs.h.al & 0x40);
JoyStick.switch_3 = BOOL(regs.h.al & 0x80);
regs.h.ah = 0x84; /* Read positions */
regs.x.dx = 1;
int86(0x15, ®s, ®s);
if (regs.x.cflag)
return ERROR;
JoyStick.pos_Ax = regs.x.ax;
JoyStick.pos_Ay = regs.x.bx;
JoyStick.pos_Bx = regs.x.cx;
JoyStick.pos_By = regs.x.dx;
return SUCCESS;
}
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