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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 9999
#define CALIBRATING_LOOPS 10
static uint16_t j_up, j_down, j_left, j_right;
static uint16_t read_axis(uint16_t *x, uint16_t *y)
{
uint16_t i, value;
uint16_t mask = AXISX | AXISY;
*x = *y = 0;
disable();
outportb(PORT, 0);
for (i = 1; mask && i < TIMEOUT; i++)
{
value = inportb(PORT) ^ mask;
if (value & AXISX)
{
*x = i;
mask ^= AXISX;
}
if (value & AXISY)
{
*y = i;
mask ^= AXISY;
}
}
enable();
return i;
}
static uint8_t calibrate_release(uint16_t *x, uint16_t *y)
{
uint8_t i;
uint16_t xacc, yacc;
while (1)
{
if (keys[KEY_ESC])
{
while (keys[KEY_ESC])
wait_vsync();
return 0;
}
xacc = yacc = 0;
for (i = 0; i < CALIBRATING_LOOPS; i++)
{
read_axis(x, y);
xacc += *x;
yacc += *y;
}
if (!(inportb(PORT) & BUTTON1))
{
while (!(inportb(PORT) & BUTTON1))
wait_vsync();
*x = xacc / CALIBRATING_LOOPS;
*y = yacc / CALIBRATING_LOOPS;
return 1;
}
wait_vsync();
}
}
static uint8_t calibrate_circle(uint16_t joy_values[4])
{
uint8_t i;
uint16_t x, y;
while (1)
{
if (keys[KEY_ESC])
{
while (keys[KEY_ESC])
wait_vsync();
return 0;
}
for (i = 0; i < CALIBRATING_LOOPS; i++)
{
read_axis(&x, &y);
// up
if (y < joy_values[0])
joy_values[0] = y;
// down
if (y > joy_values[1])
joy_values[1] = y;
// left
if (x < joy_values[2])
joy_values[2] = x;
// right
if (x > joy_values[3])
joy_values[3] = x;
}
if (!(inportb(PORT) & BUTTON1))
{
while (!(inportb(PORT) & BUTTON1))
wait_vsync();
return 1;
}
wait_vsync();
}
}
uint8_t joy_detect()
{
uint16_t xcenter, ycenter;
// this read doesn't matter
if (read_axis(&xcenter, &ycenter) == TIMEOUT)
return 0;
printf("Joystick detected!\n");
printf("Please center the joystick and press BUTTON 1 (ESC to abort)\n");
if (!calibrate_release(&xcenter, &ycenter))
return 0;
// up, down, left, right
uint16_t joy_values[4] = { ycenter, ycenter, xcenter, xcenter };
printf("Please move the joystick in circles and then press BUTTON 1 (ESC to abort)\n");
if (!calibrate_circle(joy_values))
return 0;
printf("Please center the joystick and press BUTTON 1 (ESC to abort)\n");
if (!calibrate_release(&xcenter, &ycenter))
return 0;
j_up = ycenter - ((ycenter - joy_values[0]) / 2);
j_down = ycenter + ((joy_values[1] - ycenter) / 2);
j_left = xcenter - ((xcenter - joy_values[2]) / 2);
j_right = xcenter + ((joy_values[3] - xcenter) / 2);
return 1;
}
uint8_t joy_read()
{
uint8_t r = CTL_NONE;
uint8_t b;
b = inportb(PORT);
if (!(b & BUTTON1))
r |= CTL_FIRE1;
if (!(b & BUTTON2))
r |= CTL_FIRE2;
uint16_t x, y;
read_axis(&x, &y);
if (y < j_up)
r |= CTL_UP;
if (y > j_down)
r |= CTL_DOWN;
if (x < j_left)
r |= CTL_LEFT;
if (x > j_right)
r |= CTL_RIGHT;
return r;
}
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