How can I read this digital pin for Nano by using AVR's Atmel Studo?

Question

How can I read digital pin 6 in AVR?

I set the pin as input as follows:

DDRD = B0100000; //this will set pin 6 as input

But how can I now digital read this pin?:

Another way of putting it: how can I convert this Arduino code to be used in Atmel Studio?:

digitalRead(DATA_PIN);

Edit:

while (1) {      

        unsigned long data = 0;//32 bit variable to store encoder data

        for (int i=0; i<25; i++) {//25 bit encoder data, first 12 bit is CCW count data and the rest 13 bit is the position angle data
        data <<= 1;//shift all read data left one bit   
        PORTD &= ~(1 << 5);//clock pin goes low    
        _delay_us(2);    
        PORTD |= (1 << 5);//clock pin goes high   
        _delay_us(2);   

        data |= digitalRead(DATA_PIN);//cat the new read bit to the whole read data  
        }

I want to use usual C code for AVR instead of using digitalRead above. data is an 32 bit array storing 25 bit encoder data. It is bit by bit filled by digitalRaed.

I think I found it:

while (1) {      

        unsigned long data = 0;//32 bit variable to store encoder data
        uint8_t val;

        for (int i=0; i<25; i++) {//25 bit encoder data, first 12 bit is CCW count data and the rest 13 bit is the position angle data
        data <<= 1;//shift all read data left one bit   
        PORTD &= ~(1 << 5);//clock pin goes low    
        _delay_us(2);    
        PORTD |= (1 << 5);//clock pin goes high   
        _delay_us(2);   




        if ( (PIND & (1 << PIND6)) == (1 << PIND6) ) {
            val = 1;
            } else {
            val = 0;
        }


        data |= val;//cat the new read bit to the whole read data    
        }  

Answer 1

1. Read the port state with PIND
2. Isolate the bit you want with &
3. Profit

if (PIND & 0b0100000) {
    val |= 1;
}

Or, as a ternary:

val |= ((PIND & 0b01000000) ? 1 : 0);