To check if the number is multiple of 8, the bitwise way is that: first right shift by 3 and then left shift by 3. Multiple of 8 will remain the same as original number after this operation.
Examples:
8: 1000
>> 3 : 0001
<<3 : 1000
24: 11000
>>3 : 00011
<<3 : 11000
9: 1001
>>3 : 0001
<<3 : 1000