Motorola's 32 bit cpu does the same thing. The length of an instruction is determined by the opcode. Some opcodes require 1 byte, some 2 bytes, some 8 bytes. Therefore, the program instructions are going to be misaligned. The internal structure of the cpu knows this and does byte swapping to put them in the correct sequence inside the processor. Same for a memory read, however, like Ratchit said, it is more efficient if the data words are aligned, as it may have to do an extra read to get to the final byte of data if the first byte is misaligned.