What are the required steps to convert base 10 integer
number -2 499 999 990 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:
|-2 499 999 990| = 2 499 999 990
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;
- 2 499 999 990 ÷ 2 = 1 249 999 995 + 0;
- 1 249 999 995 ÷ 2 = 624 999 997 + 1;
- 624 999 997 ÷ 2 = 312 499 998 + 1;
- 312 499 998 ÷ 2 = 156 249 999 + 0;
- 156 249 999 ÷ 2 = 78 124 999 + 1;
- 78 124 999 ÷ 2 = 39 062 499 + 1;
- 39 062 499 ÷ 2 = 19 531 249 + 1;
- 19 531 249 ÷ 2 = 9 765 624 + 1;
- 9 765 624 ÷ 2 = 4 882 812 + 0;
- 4 882 812 ÷ 2 = 2 441 406 + 0;
- 2 441 406 ÷ 2 = 1 220 703 + 0;
- 1 220 703 ÷ 2 = 610 351 + 1;
- 610 351 ÷ 2 = 305 175 + 1;
- 305 175 ÷ 2 = 152 587 + 1;
- 152 587 ÷ 2 = 76 293 + 1;
- 76 293 ÷ 2 = 38 146 + 1;
- 38 146 ÷ 2 = 19 073 + 0;
- 19 073 ÷ 2 = 9 536 + 1;
- 9 536 ÷ 2 = 4 768 + 0;
- 4 768 ÷ 2 = 2 384 + 0;
- 2 384 ÷ 2 = 1 192 + 0;
- 1 192 ÷ 2 = 596 + 0;
- 596 ÷ 2 = 298 + 0;
- 298 ÷ 2 = 149 + 0;
- 149 ÷ 2 = 74 + 1;
- 74 ÷ 2 = 37 + 0;
- 37 ÷ 2 = 18 + 1;
- 18 ÷ 2 = 9 + 0;
- 9 ÷ 2 = 4 + 1;
- 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.
2 499 999 990(10) = 1001 0101 0000 0010 1111 1000 1111 0110(2)
4. Determine the signed binary number bit length:
The base 2 number's actual length, in bits: 32.
- 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, 32,
3) so that the first bit (leftmost) could be zero
(we deal with a positive number at this moment)
=== is: 64.
5. Get the positive binary computer representation on 64 bits (8 Bytes):
If needed, add extra 0s in front (to the left) of the base 2 number, up to the required length, 64:
2 499 999 990(10) = 0000 0000 0000 0000 0000 0000 0000 0000 1001 0101 0000 0010 1111 1000 1111 0110
6. Get the negative integer number representation:
To get the negative integer number representation on 64 bits (8 Bytes),
... change the first bit (the leftmost), from 0 to 1...
-2 499 999 990(10) Base 10 integer number converted and written as a signed binary code (in base 2):
-2 499 999 990(10) = 1000 0000 0000 0000 0000 0000 0000 0000 1001 0101 0000 0010 1111 1000 1111 0110
Spaces were used to group digits: for binary, by 4, for decimal, by 3.