dword, is it 8 bytes?

No. Fire up "calc" in advanced mode, switch to binary, select DWORD and subtract "1" - now count the "1"s.


that means, from the integer a, shift some 8 bytes to left.
well, is there bytes in integer?

No, that's 8 bits.

A simple way of doing an 8 bit shift left is to multiply the number by 256.

For example, 13=1101 in binary.

13 * 256 = 3328, which is 110100000000 in binary - you will see that the 1101 has been shifted 8 bits to the left.