#include <parapin.h>
#include <stdlib.h>

#define LED_A LP_PIN02
#define LED_B LP_PIN03
#define LED_C LP_PIN04
#define LED_D LP_PIN05
#define LED_E LP_PIN06
#define LED_F LP_PIN07
#define LED_G LP_PIN08
#define LED_DP LP_PIN09

#define LED_1 LP_PIN17
#define LED_2 LP_PIN16
#define LED_3 LP_PIN14

#define LED_POSITION_MASK (LED_1 | LED_2 | LED_3)

#define LED_ALL (LED_A | LED_B | LED_C | LED_D | LED_E | LED_F | LED_G | LED_DP | LED_1 | LED_2 | LED_3)

int digit2pins[] = {
    LED_B | LED_C,
    LED_A | LED_B | LED_G | LED_E | LED_D,
    LED_A | LED_B | LED_G | LED_C | LED_D,
    LED_F | LED_G | LED_B | LED_C,
    LED_A | LED_F | LED_G | LED_C | LED_D,
    LED_A | LED_F | LED_G | LED_E | LED_C | LED_D,
    LED_A | LED_B | LED_C,
    LED_A | LED_B | LED_C | LED_D | LED_E | LED_F | LED_G,
    LED_A | LED_B | LED_C | LED_D | LED_F | LED_G
};

int position2pins[] = {
    LED_1,
    LED_2,
    LED_3
};

void turnOnDigit(int digitPosition, int value);

int main(int argc, char * argv[])
{
    /* initialize the parapin user-land library */
    pin_init_user(LPT1);

    /* set up pins as output pins */
    pin_output_mode(LED_ALL);

    if (argc == 2)
    {
        int value = atoi(argv[1]);
        turnOnDigit(2, value % 10);
    }
}

void turnOnDigit(int digitPosition, int value)
{
    /* turn all pins off */
    clear_pin(LED_ALL);

    /* enable the positional pin */
    register int pinSet = LED_POSITION_MASK & ~position2pins[digitPosition];
    pinSet |= digit2pins[value];
    set_pin(pinSet);
}