Count number of 1's in a number

Count number of 1's in a number

1. MVI B, 00H  
2. MVI C, 08H  
3. MOV A, D  
4. BACK: RAR  
5. JNC SKIP  
6. INR B  
7. SKIP: DCR C  
8. JNZ BACK  
9. HLT