What are the required steps to convert base 10 integer
number -268 468 238 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:
|-268 468 238| = 268 468 238
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;
- 268 468 238 ÷ 2 = 134 234 119 + 0;
- 134 234 119 ÷ 2 = 67 117 059 + 1;
- 67 117 059 ÷ 2 = 33 558 529 + 1;
- 33 558 529 ÷ 2 = 16 779 264 + 1;
- 16 779 264 ÷ 2 = 8 389 632 + 0;
- 8 389 632 ÷ 2 = 4 194 816 + 0;
- 4 194 816 ÷ 2 = 2 097 408 + 0;
- 2 097 408 ÷ 2 = 1 048 704 + 0;
- 1 048 704 ÷ 2 = 524 352 + 0;
- 524 352 ÷ 2 = 262 176 + 0;
- 262 176 ÷ 2 = 131 088 + 0;
- 131 088 ÷ 2 = 65 544 + 0;
- 65 544 ÷ 2 = 32 772 + 0;
- 32 772 ÷ 2 = 16 386 + 0;
- 16 386 ÷ 2 = 8 193 + 0;
- 8 193 ÷ 2 = 4 096 + 1;
- 4 096 ÷ 2 = 2 048 + 0;
- 2 048 ÷ 2 = 1 024 + 0;
- 1 024 ÷ 2 = 512 + 0;
- 512 ÷ 2 = 256 + 0;
- 256 ÷ 2 = 128 + 0;
- 128 ÷ 2 = 64 + 0;
- 64 ÷ 2 = 32 + 0;
- 32 ÷ 2 = 16 + 0;
- 16 ÷ 2 = 8 + 0;
- 8 ÷ 2 = 4 + 0;
- 4 ÷ 2 = 2 + 0;
- 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.
268 468 238(10) = 1 0000 0000 0000 1000 0000 0000 1110(2)
4. 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) 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, 29,
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:
268 468 238(10) = 0001 0000 0000 0000 1000 0000 0000 1110
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...
-268 468 238(10) Base 10 integer number converted and written as a signed binary code (in base 2):
-268 468 238(10) = 1001 0000 0000 0000 1000 0000 0000 1110
Spaces were used to group digits: for binary, by 4, for decimal, by 3.