What are the required steps to convert base 10 integer
number -135 253 521 139 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:
|-135 253 521 139| = 135 253 521 139
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;
- 135 253 521 139 ÷ 2 = 67 626 760 569 + 1;
- 67 626 760 569 ÷ 2 = 33 813 380 284 + 1;
- 33 813 380 284 ÷ 2 = 16 906 690 142 + 0;
- 16 906 690 142 ÷ 2 = 8 453 345 071 + 0;
- 8 453 345 071 ÷ 2 = 4 226 672 535 + 1;
- 4 226 672 535 ÷ 2 = 2 113 336 267 + 1;
- 2 113 336 267 ÷ 2 = 1 056 668 133 + 1;
- 1 056 668 133 ÷ 2 = 528 334 066 + 1;
- 528 334 066 ÷ 2 = 264 167 033 + 0;
- 264 167 033 ÷ 2 = 132 083 516 + 1;
- 132 083 516 ÷ 2 = 66 041 758 + 0;
- 66 041 758 ÷ 2 = 33 020 879 + 0;
- 33 020 879 ÷ 2 = 16 510 439 + 1;
- 16 510 439 ÷ 2 = 8 255 219 + 1;
- 8 255 219 ÷ 2 = 4 127 609 + 1;
- 4 127 609 ÷ 2 = 2 063 804 + 1;
- 2 063 804 ÷ 2 = 1 031 902 + 0;
- 1 031 902 ÷ 2 = 515 951 + 0;
- 515 951 ÷ 2 = 257 975 + 1;
- 257 975 ÷ 2 = 128 987 + 1;
- 128 987 ÷ 2 = 64 493 + 1;
- 64 493 ÷ 2 = 32 246 + 1;
- 32 246 ÷ 2 = 16 123 + 0;
- 16 123 ÷ 2 = 8 061 + 1;
- 8 061 ÷ 2 = 4 030 + 1;
- 4 030 ÷ 2 = 2 015 + 0;
- 2 015 ÷ 2 = 1 007 + 1;
- 1 007 ÷ 2 = 503 + 1;
- 503 ÷ 2 = 251 + 1;
- 251 ÷ 2 = 125 + 1;
- 125 ÷ 2 = 62 + 1;
- 62 ÷ 2 = 31 + 0;
- 31 ÷ 2 = 15 + 1;
- 15 ÷ 2 = 7 + 1;
- 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.
135 253 521 139(10) = 1 1111 0111 1101 1011 1100 1111 0010 1111 0011(2)
4. Determine the signed binary number bit length:
The base 2 number's actual length, in bits: 37.
- 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, 37,
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:
135 253 521 139(10) = 0000 0000 0000 0000 0000 0000 0001 1111 0111 1101 1011 1100 1111 0010 1111 0011
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...
-135 253 521 139(10) Base 10 integer number converted and written as a signed binary code (in base 2):
-135 253 521 139(10) = 1000 0000 0000 0000 0000 0000 0001 1111 0111 1101 1011 1100 1111 0010 1111 0011
Spaces were used to group digits: for binary, by 4, for decimal, by 3.