Convert -274 877 906 986 to a Signed Binary in Two's (2's) Complement Representation
How to convert decimal number -274 877 906 986(10) to a signed binary in two's (2's) complement representation
What are the steps to convert decimal number
-274 877 906 986 to a signed binary in two's (2's) complement representation?
- 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:
|-274 877 906 986| = 274 877 906 986
2. Divide the number repeatedly by 2:
Keep track of each remainder.
We stop when we get a quotient that is equal to zero.
- division = quotient + remainder;
- 274 877 906 986 ÷ 2 = 137 438 953 493 + 0;
- 137 438 953 493 ÷ 2 = 68 719 476 746 + 1;
- 68 719 476 746 ÷ 2 = 34 359 738 373 + 0;
- 34 359 738 373 ÷ 2 = 17 179 869 186 + 1;
- 17 179 869 186 ÷ 2 = 8 589 934 593 + 0;
- 8 589 934 593 ÷ 2 = 4 294 967 296 + 1;
- 4 294 967 296 ÷ 2 = 2 147 483 648 + 0;
- 2 147 483 648 ÷ 2 = 1 073 741 824 + 0;
- 1 073 741 824 ÷ 2 = 536 870 912 + 0;
- 536 870 912 ÷ 2 = 268 435 456 + 0;
- 268 435 456 ÷ 2 = 134 217 728 + 0;
- 134 217 728 ÷ 2 = 67 108 864 + 0;
- 67 108 864 ÷ 2 = 33 554 432 + 0;
- 33 554 432 ÷ 2 = 16 777 216 + 0;
- 16 777 216 ÷ 2 = 8 388 608 + 0;
- 8 388 608 ÷ 2 = 4 194 304 + 0;
- 4 194 304 ÷ 2 = 2 097 152 + 0;
- 2 097 152 ÷ 2 = 1 048 576 + 0;
- 1 048 576 ÷ 2 = 524 288 + 0;
- 524 288 ÷ 2 = 262 144 + 0;
- 262 144 ÷ 2 = 131 072 + 0;
- 131 072 ÷ 2 = 65 536 + 0;
- 65 536 ÷ 2 = 32 768 + 0;
- 32 768 ÷ 2 = 16 384 + 0;
- 16 384 ÷ 2 = 8 192 + 0;
- 8 192 ÷ 2 = 4 096 + 0;
- 4 096 ÷ 2 = 2 048 + 0;
- 2 048 ÷ 2 = 1 024 + 0;
- 1 024 ÷ 2 = 512 + 0;
- 512 ÷ 2 = 256 + 0;
- 256 ÷ 2 = 128 + 0;
- 128 ÷ 2 = 64 + 0;
- 64 ÷ 2 = 32 + 0;
- 32 ÷ 2 = 16 + 0;
- 16 ÷ 2 = 8 + 0;
- 8 ÷ 2 = 4 + 0;
- 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.
274 877 906 986(10) = 100 0000 0000 0000 0000 0000 0000 0000 0010 1010(2)
4. Determine the signed binary number bit length:
The base 2 number's actual length, in bits: 39.
- 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) indicates 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, 39,
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.
274 877 906 986(10) = 0000 0000 0000 0000 0000 0000 0100 0000 0000 0000 0000 0000 0000 0000 0010 1010
6. Get the negative integer number representation. Part 1:
- To write the negative integer number on 64 bits (8 Bytes), as a signed binary in one's complement representation, replace all the bits on 0 with 1s and all the bits set on 1 with 0s.
Reverse the digits, flip the digits:
Replace the bits set on 0 with 1s and the bits set on 1 with 0s.
!(0000 0000 0000 0000 0000 0000 0100 0000 0000 0000 0000 0000 0000 0000 0010 1010)
= 1111 1111 1111 1111 1111 1111 1011 1111 1111 1111 1111 1111 1111 1111 1101 0101
7. Get the negative integer number representation. Part 2:
- To write the negative integer number on 64 bits (8 Bytes), as a signed binary in two's complement representation, add 1 to the number calculated above 1111 1111 1111 1111 1111 1111 1011 1111 1111 1111 1111 1111 1111 1111 1101 0101 (to the signed binary in one's complement representation).
Binary addition carries on a value of 2:
- 0 + 0 = 0
- 0 + 1 = 1
- 1 + 1 = 10
- 1 + 10 = 11
- 1 + 11 = 100
Add 1 to the number calculated above
(to the signed binary number in one's complement representation):
-274 877 906 986 =
1111 1111 1111 1111 1111 1111 1011 1111 1111 1111 1111 1111 1111 1111 1101 0101 + 1
Decimal Number -274 877 906 986(10) converted to signed binary in two's complement representation:
-274 877 906 986(10) = 1111 1111 1111 1111 1111 1111 1011 1111 1111 1111 1111 1111 1111 1111 1101 0110
Spaces were used to group digits: for binary, by 4, for decimal, by 3.