What are the required steps to convert base 10 integer
number -643 436 282 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:
|-643 436 282| = 643 436 282
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;
- 643 436 282 ÷ 2 = 321 718 141 + 0;
- 321 718 141 ÷ 2 = 160 859 070 + 1;
- 160 859 070 ÷ 2 = 80 429 535 + 0;
- 80 429 535 ÷ 2 = 40 214 767 + 1;
- 40 214 767 ÷ 2 = 20 107 383 + 1;
- 20 107 383 ÷ 2 = 10 053 691 + 1;
- 10 053 691 ÷ 2 = 5 026 845 + 1;
- 5 026 845 ÷ 2 = 2 513 422 + 1;
- 2 513 422 ÷ 2 = 1 256 711 + 0;
- 1 256 711 ÷ 2 = 628 355 + 1;
- 628 355 ÷ 2 = 314 177 + 1;
- 314 177 ÷ 2 = 157 088 + 1;
- 157 088 ÷ 2 = 78 544 + 0;
- 78 544 ÷ 2 = 39 272 + 0;
- 39 272 ÷ 2 = 19 636 + 0;
- 19 636 ÷ 2 = 9 818 + 0;
- 9 818 ÷ 2 = 4 909 + 0;
- 4 909 ÷ 2 = 2 454 + 1;
- 2 454 ÷ 2 = 1 227 + 0;
- 1 227 ÷ 2 = 613 + 1;
- 613 ÷ 2 = 306 + 1;
- 306 ÷ 2 = 153 + 0;
- 153 ÷ 2 = 76 + 1;
- 76 ÷ 2 = 38 + 0;
- 38 ÷ 2 = 19 + 0;
- 19 ÷ 2 = 9 + 1;
- 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.
643 436 282(10) = 10 0110 0101 1010 0000 1110 1111 1010(2)
4. Determine the signed binary number bit length:
The base 2 number's actual length, in bits: 30.
- 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, 30,
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:
643 436 282(10) = 0010 0110 0101 1010 0000 1110 1111 1010
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...
-643 436 282(10) Base 10 integer number converted and written as a signed binary code (in base 2):
-643 436 282(10) = 1010 0110 0101 1010 0000 1110 1111 1010
Spaces were used to group digits: for binary, by 4, for decimal, by 3.