What are the required steps to convert base 10 integer
number -125 235 349 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:
|-125 235 349| = 125 235 349
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;
- 125 235 349 ÷ 2 = 62 617 674 + 1;
- 62 617 674 ÷ 2 = 31 308 837 + 0;
- 31 308 837 ÷ 2 = 15 654 418 + 1;
- 15 654 418 ÷ 2 = 7 827 209 + 0;
- 7 827 209 ÷ 2 = 3 913 604 + 1;
- 3 913 604 ÷ 2 = 1 956 802 + 0;
- 1 956 802 ÷ 2 = 978 401 + 0;
- 978 401 ÷ 2 = 489 200 + 1;
- 489 200 ÷ 2 = 244 600 + 0;
- 244 600 ÷ 2 = 122 300 + 0;
- 122 300 ÷ 2 = 61 150 + 0;
- 61 150 ÷ 2 = 30 575 + 0;
- 30 575 ÷ 2 = 15 287 + 1;
- 15 287 ÷ 2 = 7 643 + 1;
- 7 643 ÷ 2 = 3 821 + 1;
- 3 821 ÷ 2 = 1 910 + 1;
- 1 910 ÷ 2 = 955 + 0;
- 955 ÷ 2 = 477 + 1;
- 477 ÷ 2 = 238 + 1;
- 238 ÷ 2 = 119 + 0;
- 119 ÷ 2 = 59 + 1;
- 59 ÷ 2 = 29 + 1;
- 29 ÷ 2 = 14 + 1;
- 14 ÷ 2 = 7 + 0;
- 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.
125 235 349(10) = 111 0111 0110 1111 0000 1001 0101(2)
4. Determine the signed binary number bit length:
The base 2 number's actual length, in bits: 27.
- 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, 27,
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:
125 235 349(10) = 0000 0111 0111 0110 1111 0000 1001 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...
-125 235 349(10) Base 10 integer number converted and written as a signed binary code (in base 2):
-125 235 349(10) = 1000 0111 0111 0110 1111 0000 1001 0101
Spaces were used to group digits: for binary, by 4, for decimal, by 3.