What are the required steps to convert base 10 integer
number -1 189 871 621 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:
|-1 189 871 621| = 1 189 871 621
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;
- 1 189 871 621 ÷ 2 = 594 935 810 + 1;
- 594 935 810 ÷ 2 = 297 467 905 + 0;
- 297 467 905 ÷ 2 = 148 733 952 + 1;
- 148 733 952 ÷ 2 = 74 366 976 + 0;
- 74 366 976 ÷ 2 = 37 183 488 + 0;
- 37 183 488 ÷ 2 = 18 591 744 + 0;
- 18 591 744 ÷ 2 = 9 295 872 + 0;
- 9 295 872 ÷ 2 = 4 647 936 + 0;
- 4 647 936 ÷ 2 = 2 323 968 + 0;
- 2 323 968 ÷ 2 = 1 161 984 + 0;
- 1 161 984 ÷ 2 = 580 992 + 0;
- 580 992 ÷ 2 = 290 496 + 0;
- 290 496 ÷ 2 = 145 248 + 0;
- 145 248 ÷ 2 = 72 624 + 0;
- 72 624 ÷ 2 = 36 312 + 0;
- 36 312 ÷ 2 = 18 156 + 0;
- 18 156 ÷ 2 = 9 078 + 0;
- 9 078 ÷ 2 = 4 539 + 0;
- 4 539 ÷ 2 = 2 269 + 1;
- 2 269 ÷ 2 = 1 134 + 1;
- 1 134 ÷ 2 = 567 + 0;
- 567 ÷ 2 = 283 + 1;
- 283 ÷ 2 = 141 + 1;
- 141 ÷ 2 = 70 + 1;
- 70 ÷ 2 = 35 + 0;
- 35 ÷ 2 = 17 + 1;
- 17 ÷ 2 = 8 + 1;
- 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.
1 189 871 621(10) = 100 0110 1110 1100 0000 0000 0000 0101(2)
4. Determine the signed binary number bit length:
The base 2 number's actual length, in bits: 31.
- 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, 31,
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:
1 189 871 621(10) = 0100 0110 1110 1100 0000 0000 0000 0101
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...
-1 189 871 621(10) Base 10 integer number converted and written as a signed binary code (in base 2):
-1 189 871 621(10) = 1100 0110 1110 1100 0000 0000 0000 0101
Spaces were used to group digits: for binary, by 4, for decimal, by 3.