What are the required steps to convert base 10 integer
number -398 443 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:
|-398 443| = 398 443
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;
- 398 443 ÷ 2 = 199 221 + 1;
- 199 221 ÷ 2 = 99 610 + 1;
- 99 610 ÷ 2 = 49 805 + 0;
- 49 805 ÷ 2 = 24 902 + 1;
- 24 902 ÷ 2 = 12 451 + 0;
- 12 451 ÷ 2 = 6 225 + 1;
- 6 225 ÷ 2 = 3 112 + 1;
- 3 112 ÷ 2 = 1 556 + 0;
- 1 556 ÷ 2 = 778 + 0;
- 778 ÷ 2 = 389 + 0;
- 389 ÷ 2 = 194 + 1;
- 194 ÷ 2 = 97 + 0;
- 97 ÷ 2 = 48 + 1;
- 48 ÷ 2 = 24 + 0;
- 24 ÷ 2 = 12 + 0;
- 12 ÷ 2 = 6 + 0;
- 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.
398 443(10) = 110 0001 0100 0110 1011(2)
4. Determine the signed binary number bit length:
The base 2 number's actual length, in bits: 19.
- 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, 19,
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:
398 443(10) = 0000 0000 0000 0110 0001 0100 0110 1011
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...
-398 443(10) Base 10 integer number converted and written as a signed binary code (in base 2):
-398 443(10) = 1000 0000 0000 0110 0001 0100 0110 1011
Spaces were used to group digits: for binary, by 4, for decimal, by 3.