What are the required steps to convert base 10 integer
number -220 660 to signed binary code (in base 2)?
- A signed integer, written in base ten, or a decimal system number, is a number written using the digits 0 through 9 and the sign, which can be positive (+) or negative (-). If positive, the sign is usually not written. A number written in base two, or binary, is a number written using only the digits 0 and 1.
1. Start with the positive version of the number:
|-220 660| = 220 660
2. Divide the number repeatedly by 2:
Keep track of each remainder.
Stop when you get a quotient that is equal to zero.
- division = quotient + remainder;
- 220 660 ÷ 2 = 110 330 + 0;
- 110 330 ÷ 2 = 55 165 + 0;
- 55 165 ÷ 2 = 27 582 + 1;
- 27 582 ÷ 2 = 13 791 + 0;
- 13 791 ÷ 2 = 6 895 + 1;
- 6 895 ÷ 2 = 3 447 + 1;
- 3 447 ÷ 2 = 1 723 + 1;
- 1 723 ÷ 2 = 861 + 1;
- 861 ÷ 2 = 430 + 1;
- 430 ÷ 2 = 215 + 0;
- 215 ÷ 2 = 107 + 1;
- 107 ÷ 2 = 53 + 1;
- 53 ÷ 2 = 26 + 1;
- 26 ÷ 2 = 13 + 0;
- 13 ÷ 2 = 6 + 1;
- 6 ÷ 2 = 3 + 0;
- 3 ÷ 2 = 1 + 1;
- 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.
220 660(10) = 11 0101 1101 1111 0100(2)
4. Determine the signed binary number bit length:
The base 2 number's actual length, in bits: 18.
- 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) is reserved for 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, 18,
3) so that the first bit (leftmost) could be zero
(we deal with a positive number at this moment)
=== is: 32.
5. 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:
220 660(10) = 0000 0000 0000 0011 0101 1101 1111 0100
6. Get the negative integer number representation:
To get the negative integer number representation on 32 bits (4 Bytes),
... change the first bit (the leftmost), from 0 to 1...
-220 660(10) Base 10 integer number converted and written as a signed binary code (in base 2):
-220 660(10) = 1000 0000 0000 0011 0101 1101 1111 0100
Spaces were used to group digits: for binary, by 4, for decimal, by 3.