How to convert a signed integer in decimal system (in base 10):
-87 713(10)
to a signed binary one's complement representation
1. Start with the positive version of the number:
|-87 713| = 87 713
2. 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;
- 87 713 ÷ 2 = 43 856 + 1;
- 43 856 ÷ 2 = 21 928 + 0;
- 21 928 ÷ 2 = 10 964 + 0;
- 10 964 ÷ 2 = 5 482 + 0;
- 5 482 ÷ 2 = 2 741 + 0;
- 2 741 ÷ 2 = 1 370 + 1;
- 1 370 ÷ 2 = 685 + 0;
- 685 ÷ 2 = 342 + 1;
- 342 ÷ 2 = 171 + 0;
- 171 ÷ 2 = 85 + 1;
- 85 ÷ 2 = 42 + 1;
- 42 ÷ 2 = 21 + 0;
- 21 ÷ 2 = 10 + 1;
- 10 ÷ 2 = 5 + 0;
- 5 ÷ 2 = 2 + 1;
- 2 ÷ 2 = 1 + 0;
- 1 ÷ 2 = 0 + 1;
3. Construct the base 2 representation of the positive number:
Take all the remainders starting from the bottom of the list constructed above.
87 713(10) = 1 0101 0110 1010 0001(2)
4. Determine the signed binary number bit length:
The base 2 number's actual length, in bits: 17.
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; ...
First bit (the leftmost) indicates the sign,
1 = negative, 0 = positive.
The least number that is:
a power of 2
and is larger than the actual length, 17,
so that the first bit (leftmost) could be zero
(we deal with a positive number at this moment)
is: 32.
5. 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:
87 713(10) = 0000 0000 0000 0001 0101 0110 1010 0001
6. Get the negative integer number representation:
To get the negative integer number representation on 32 bits (4 Bytes),
signed binary one's complement,
replace all the bits on 0 with 1s
and all the bits set on 1 with 0s
(reverse the digits, flip the digits)
!(0000 0000 0000 0001 0101 0110 1010 0001) =
1111 1111 1111 1110 1010 1001 0101 1110
Conclusion:
Number -87 713, a signed integer, converted from decimal system (base 10) to a signed binary one's complement representation:
-87 713(10) = 1111 1111 1111 1110 1010 1001 0101 1110
Spaces used to group digits: for binary, by 4; for decimal, by 3.
More operations of this kind:
Convert signed integer numbers from the decimal system (base ten) to signed binary one's complement representation