Attiny13 pin change interrupts

#include <avr/io.h>

#include <avr/interrupt.h>

#include <avr/delay.h>

#include <avr/sleep.h>

  volatile uint8_t auf;

  volatile uint8_t zu;

  ISR(PCINT){

    if(PINB & 0b00000001)

      auf=1;

    if(PINB & 0b00000010)

      zu=1;

  }

void open(){

  PORTB &= ~(0b00000100);

  _delay_ms(500);

  PORTB |= 0b00000100;

  _delay_ms(50);  

}

void close(){

  PORTB &= ~(0b00001000);

  _delay_ms(500);

  PORTB |= 0b00001000;

  _delay_ms(50);

}

int main(void)

{

    DDRB |= 0b00001100;     //set pins 2 and 3 as output

  PORTB |= 0b00001100;     //set pins 2 and 3 high

  PCMSK = 0x03;       //enable pcint0 and 1  

  GIMSK |= PCIE;

  sei();           //enable interrupts

    while (1) 

    {

    if(auf){

      open();

      auf=0;

    }

    if(zu){

      close();

      zu=0;

    }

    //set_sleep_mode(SLEEP_MODE_PWR_DOWN);

    //sleep_mode();

    }

}