When a 64 bit OS runs on a 64 bit processor, the processor processes the whole 64 bit (8 bytes) in one go. Suppose a 32 bit OS runs on a 64 bit processor, how is data extracted? Is 32 bits (4bytes) extracted or whole 64 (8 bytes)? Is that 32 bit (4byte) data stored like 32 bits storage wastage and 32 bits as data ? Like (32bit(zeroes) + 32 bit (data)) for 64 bit processor 32 bit OS?