/**
 * This is the timer interrupt which generates the output.
 */
void __ISR(_TIMER_5_VECTOR, ipl1) Timer5Handler(void) {

    /* Clear TMR5 interrupt flag. */
    IFS0bits.T5IF = 0;

    column = wrapAround(increment(column), IMAGE_WIDTH);
    semaphore = 1;
}

int main() {

    /* (...) */

    while (1) {
        if (semaphore != 0) {
            semaphore = 0;
            printout(column);
        }
    }
    return 0;
}