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#include <stdint.h>
#include <stdio.h>
#include <pc.h>
#include <dos.h>
#include "vga.h"
#include "keyb.h"
#include "control.h"
#include "joy.h"
#define PORT 0x201
#define BUTTON1 0x10
#define BUTTON2 0x20
#define AXISX 1
#define AXISY 2
#define TIMEOUT 16000
static uint16_t j_up, j_down, j_left, j_right;
static uint16_t read_axis(uint8_t axis)
{
uint16_t i;
disable();
outportb(PORT, 0xff);
for (i = 0; i < TIMEOUT; i++)
if (!(inportb(PORT) & axis))
break;
enable();
return i;
}
static uint8_t calibrate(uint16_t *v, uint16_t *h)
{
while (1)
{
if (keys[KEY_ESC])
{
while (keys[KEY_ESC])
wait_vsync();
return 0;
}
*v = read_axis(AXISY);
*h = read_axis(AXISX);
if (!(inportb(PORT) & BUTTON1))
{
while (!(inportb(PORT) & BUTTON1))
wait_vsync();
return 1;
}
wait_vsync();
}
}
uint8_t joy_detect()
{
if (read_axis(AXISX) == TIMEOUT)
return 0;
printf("Joystick detected!\n");
uint16_t cx, cy;
printf("Please center the joystick and press BUTTON 1 (ESC to abort)\n");
if (!calibrate(&cy, &cx))
return 0;
printf("Please move UP + LEFT and press BUTTON 1 (ESC to abort)\n");
if (!calibrate(&j_up, &j_left))
return 0;
printf("Please move DOWN + RIGHT and press BUTTON 1 (ESC to abort)\n");
if (!calibrate(&j_down, &j_right))
return 0;
#ifdef DEBUG
printf("Joystick reads: up=%04d, down=%04d, left=%04d, right=%04d\n",
j_up, j_down, j_left, j_right);
#endif
j_up = cy - ((cy - j_up) / 2);
j_down = cy + ((j_down - cy) / 2);
j_left = cx - ((cx - j_left) / 2);
j_right = cx + ((j_right - cx) / 2);
#ifdef DEBUG
printf(" Adjusted: up=%04d, down=%04d, left=%04d, right=%04d\n",
j_up, j_down, j_left, j_right);
printf("(press X to continue)\n");
while (!keys[KEY_X])
wait_vsync();
#endif
return 1;
}
uint8_t joy_read()
{
uint8_t r = CTL_NONE;
uint8_t b;
uint16_t v;
b = inportb(PORT);
if (!(b & BUTTON1))
r |= CTL_FIRE1;
if (!(b & BUTTON2))
r |= CTL_FIRE2;
v = read_axis(AXISY);
if (v < j_up)
r |= CTL_UP;
if (v > j_down)
r |= CTL_DOWN;
v = read_axis(AXISX);
if (v < j_left)
r |= CTL_LEFT;
if (v > j_right)
r |= CTL_RIGHT;
return r;
}
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