What are the required steps to convert base 10 integer
number -2 146 322 991 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:
|-2 146 322 991| = 2 146 322 991
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;
- 2 146 322 991 ÷ 2 = 1 073 161 495 + 1;
- 1 073 161 495 ÷ 2 = 536 580 747 + 1;
- 536 580 747 ÷ 2 = 268 290 373 + 1;
- 268 290 373 ÷ 2 = 134 145 186 + 1;
- 134 145 186 ÷ 2 = 67 072 593 + 0;
- 67 072 593 ÷ 2 = 33 536 296 + 1;
- 33 536 296 ÷ 2 = 16 768 148 + 0;
- 16 768 148 ÷ 2 = 8 384 074 + 0;
- 8 384 074 ÷ 2 = 4 192 037 + 0;
- 4 192 037 ÷ 2 = 2 096 018 + 1;
- 2 096 018 ÷ 2 = 1 048 009 + 0;
- 1 048 009 ÷ 2 = 524 004 + 1;
- 524 004 ÷ 2 = 262 002 + 0;
- 262 002 ÷ 2 = 131 001 + 0;
- 131 001 ÷ 2 = 65 500 + 1;
- 65 500 ÷ 2 = 32 750 + 0;
- 32 750 ÷ 2 = 16 375 + 0;
- 16 375 ÷ 2 = 8 187 + 1;
- 8 187 ÷ 2 = 4 093 + 1;
- 4 093 ÷ 2 = 2 046 + 1;
- 2 046 ÷ 2 = 1 023 + 0;
- 1 023 ÷ 2 = 511 + 1;
- 511 ÷ 2 = 255 + 1;
- 255 ÷ 2 = 127 + 1;
- 127 ÷ 2 = 63 + 1;
- 63 ÷ 2 = 31 + 1;
- 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.
2 146 322 991(10) = 111 1111 1110 1110 0100 1010 0010 1111(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:
2 146 322 991(10) = 0111 1111 1110 1110 0100 1010 0010 1111
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...
-2 146 322 991(10) Base 10 integer number converted and written as a signed binary code (in base 2):
-2 146 322 991(10) = 1111 1111 1110 1110 0100 1010 0010 1111
Spaces were used to group digits: for binary, by 4, for decimal, by 3.