#define __AVR_ATmega644P__
#include <avr/io.h>



uint8_t getPortA4() {
    return (PINA & 0b00010000) >> 4;
}

uint8_t getPortB54() {
    return (PINB & 0b00110000) >> 4;
}

void init() {
    //DDR -> Data Direction Register
    DDRA = 0b11110111;
    DDRB = 0b11110011;
    DDRC = 0b11111111;
    DDRD = 0b00000000;
}

int main(void) {
    init();

    while(1) {
        if(getPortA4() == 0) {
            if(getPortB54() == 0b00) {
                PORTC = 0x00;
            } else if(getPortB54() == 0b01) {
                PORTC = PIND;
            } else if(getPortB54() == 0b10) {
                // 0101 0001
                uint8_t links = PIND << 4; //  0001 0000
                uint8_t rechts = PIND >> 4; // 0000 0101
                PORTC = links | rechts;
            } else if(getPortB54() == 0b11) {
                PORTC = 0xFF;
            }
        }
    }
}