PIC P16F690;

# enable gpsim as a simulator
pragma simulator gpsim;

Main {
    digital_output PORTC;
    $display = 0x08; # create a 8-bit register by checking size
    sim_assert $display == 0x08, "$display should be 0x08";
    Loop {
        write PORTC, $display;
        delay 100ms;
        # improve this depiction
        # circular rotate right by 1 bit
        ror $display, 1;
    }
}

Simulator {
    attach_led PORTC, 4; # attach 4 LEDs to PORTC on RC0-RC3;
    stop_after 60s;
    logfile "rotater.lxt";
    log PORTC;
    scope PORTC;
}