Division
- Division can be re-expressed as repeated subtraction:
- To divide 21 by 7 see how many times you can subtract 7 from 21.
- Of course, this is the same as adding -7, so we use two's complement notation.
21 is represented as 010101
7 is 000111, so -7 is 111001
|
0 1 0 1 0 1 + 1 1 1 0 0 1 (1) 0 0 1 1 1 0 + 1 1 1 0 0 1 (10) 0 0 0 1 1 1 + 1 1 1 0 0 1 (11) 0 0 0 0 0 0 |
Since we're using 6 bit patterns the extra carry bits would normally be discarded, but notice that they contain the integer part of the answer.
The 6 bits to their right contain the remainder.
So 21 divided by 7 is 3, with 0 remainder.