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Amiga CD-Sensation: Golden Games
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Amiga CD-Sensation - Ausgabe 2 - Golden Games (1996)(GTI - Schatztruhe)(DE)[!].iso
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ShuffleRun
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Joystick.c
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C/C++ Source or Header
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1993-02-13
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2KB
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63 lines
/* Joystick() */
/* Joystick() is a handy, easy and fast but naughty function that hits */
/* the hardware of the Amiga. It looks at either port 1 or port 2, and */
/* returns a bitfield containing the position of the stick and the */
/* present state of the button. */
/* */
/* Synopsis: value = Joystick( port ); */
/* value: (UBYTE) If the fire button is pressed, the first bit is */
/* set. If the stick is moved to the right, the second bit */
/* is set, and if the stick is moved to the left, the third */
/* bit is set. The fourth bit is set if the stick is moved */
/* down, and the fifth bit is set if the stick is moved up. */
/* port: (UBYTE) Set the flag PORT1 if you want to check the first */
/* (mouse) port, or set the flag PORT2 if you want to check */
/* the second (joystick) port. */
#include <hardware/custom.h>
#include <hardware/cia.h>
#define CIAAPRA 0xBFE001
#define FIRE 1
#define RIGHT 2
#define LEFT 4
#define DOWN 8
#define UP 16
#define PORT1 1
#define PORT2 2
extern __far struct Custom custom;
struct CIA *cia = (struct CIA *) CIAAPRA;
UBYTE Joystick();
UBYTE Joystick( port )
UBYTE port;
{
UBYTE data = 0;
UWORD joy;
if( port == PORT1 )
{
/* PORT 1 ("MOUSE PORT") */
joy = custom.joy0dat;
data += !( cia->ciapra & 0x0040 ) ? FIRE : 0;
}
else
{
/* PORT 2 ("JOYSTICK PORT") */
joy = custom.joy1dat;
data += !( cia->ciapra & 0x0080 ) ? FIRE : 0;
}
data += joy & 0x0002 ? RIGHT : 0;
data += joy & 0x0200 ? LEFT : 0;
data += (joy >> 1 ^ joy) & 0x0001 ? DOWN : 0;
data += (joy >> 1 ^ joy) & 0x0100 ? UP : 0;
return( data );
}