1. Divide the number repeatedly by 2:
Keep track of each remainder.
We stop when we get a quotient that is equal to zero.
- division = quotient + remainder;
- 385 421 655 ÷ 2 = 192 710 827 + 1;
- 192 710 827 ÷ 2 = 96 355 413 + 1;
- 96 355 413 ÷ 2 = 48 177 706 + 1;
- 48 177 706 ÷ 2 = 24 088 853 + 0;
- 24 088 853 ÷ 2 = 12 044 426 + 1;
- 12 044 426 ÷ 2 = 6 022 213 + 0;
- 6 022 213 ÷ 2 = 3 011 106 + 1;
- 3 011 106 ÷ 2 = 1 505 553 + 0;
- 1 505 553 ÷ 2 = 752 776 + 1;
- 752 776 ÷ 2 = 376 388 + 0;
- 376 388 ÷ 2 = 188 194 + 0;
- 188 194 ÷ 2 = 94 097 + 0;
- 94 097 ÷ 2 = 47 048 + 1;
- 47 048 ÷ 2 = 23 524 + 0;
- 23 524 ÷ 2 = 11 762 + 0;
- 11 762 ÷ 2 = 5 881 + 0;
- 5 881 ÷ 2 = 2 940 + 1;
- 2 940 ÷ 2 = 1 470 + 0;
- 1 470 ÷ 2 = 735 + 0;
- 735 ÷ 2 = 367 + 1;
- 367 ÷ 2 = 183 + 1;
- 183 ÷ 2 = 91 + 1;
- 91 ÷ 2 = 45 + 1;
- 45 ÷ 2 = 22 + 1;
- 22 ÷ 2 = 11 + 0;
- 11 ÷ 2 = 5 + 1;
- 5 ÷ 2 = 2 + 1;
- 2 ÷ 2 = 1 + 0;
- 1 ÷ 2 = 0 + 1;
2. Construct the base 2 representation of the positive number:
Take all the remainders starting from the bottom of the list constructed above.
385 421 655(10) = 1 0110 1111 1001 0001 0001 0101 0111(2)
3. Determine the signed binary number bit length:
The base 2 number's actual length, in bits: 29.
- A signed binary's bit length must be equal to a power of 2, as of:
- 21 = 2; 22 = 4; 23 = 8; 24 = 16; 25 = 32; 26 = 64; ...
- The first bit (the leftmost) indicates the sign:
- 0 = positive integer number, 1 = negative integer number
The least number that is:
1) a power of 2
2) and is larger than the actual length, 29,
3) so that the first bit (leftmost) could be zero
(we deal with a positive number at this moment)
=== is: 32.
4. Get the positive binary computer representation on 32 bits (4 Bytes):
If needed, add extra 0s in front (to the left) of the base 2 number, up to the required length, 32.
Decimal Number 385 421 655(10) converted to signed binary in two's complement representation:
Spaces were used to group digits: for binary, by 4, for decimal, by 3.