What are the required steps to convert base 10 integer
number -256 990 259 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:
|-256 990 259| = 256 990 259
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;
- 256 990 259 ÷ 2 = 128 495 129 + 1;
- 128 495 129 ÷ 2 = 64 247 564 + 1;
- 64 247 564 ÷ 2 = 32 123 782 + 0;
- 32 123 782 ÷ 2 = 16 061 891 + 0;
- 16 061 891 ÷ 2 = 8 030 945 + 1;
- 8 030 945 ÷ 2 = 4 015 472 + 1;
- 4 015 472 ÷ 2 = 2 007 736 + 0;
- 2 007 736 ÷ 2 = 1 003 868 + 0;
- 1 003 868 ÷ 2 = 501 934 + 0;
- 501 934 ÷ 2 = 250 967 + 0;
- 250 967 ÷ 2 = 125 483 + 1;
- 125 483 ÷ 2 = 62 741 + 1;
- 62 741 ÷ 2 = 31 370 + 1;
- 31 370 ÷ 2 = 15 685 + 0;
- 15 685 ÷ 2 = 7 842 + 1;
- 7 842 ÷ 2 = 3 921 + 0;
- 3 921 ÷ 2 = 1 960 + 1;
- 1 960 ÷ 2 = 980 + 0;
- 980 ÷ 2 = 490 + 0;
- 490 ÷ 2 = 245 + 0;
- 245 ÷ 2 = 122 + 1;
- 122 ÷ 2 = 61 + 0;
- 61 ÷ 2 = 30 + 1;
- 30 ÷ 2 = 15 + 0;
- 15 ÷ 2 = 7 + 1;
- 7 ÷ 2 = 3 + 1;
- 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.
256 990 259(10) = 1111 0101 0001 0101 1100 0011 0011(2)
4. Determine the signed binary number bit length:
The base 2 number's actual length, in bits: 28.
- 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, 28,
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:
256 990 259(10) = 0000 1111 0101 0001 0101 1100 0011 0011
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...
-256 990 259(10) Base 10 integer number converted and written as a signed binary code (in base 2):
-256 990 259(10) = 1000 1111 0101 0001 0101 1100 0011 0011
Spaces were used to group digits: for binary, by 4, for decimal, by 3.