Convert -142 999 999 885 to a Signed Binary in Two's (2's) Complement Representation
How to convert decimal number -142 999 999 885(10) to a signed binary in two's (2's) complement representation
What are the steps to convert decimal number
-142 999 999 885 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:
|-142 999 999 885| = 142 999 999 885
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;
- 142 999 999 885 ÷ 2 = 71 499 999 942 + 1;
- 71 499 999 942 ÷ 2 = 35 749 999 971 + 0;
- 35 749 999 971 ÷ 2 = 17 874 999 985 + 1;
- 17 874 999 985 ÷ 2 = 8 937 499 992 + 1;
- 8 937 499 992 ÷ 2 = 4 468 749 996 + 0;
- 4 468 749 996 ÷ 2 = 2 234 374 998 + 0;
- 2 234 374 998 ÷ 2 = 1 117 187 499 + 0;
- 1 117 187 499 ÷ 2 = 558 593 749 + 1;
- 558 593 749 ÷ 2 = 279 296 874 + 1;
- 279 296 874 ÷ 2 = 139 648 437 + 0;
- 139 648 437 ÷ 2 = 69 824 218 + 1;
- 69 824 218 ÷ 2 = 34 912 109 + 0;
- 34 912 109 ÷ 2 = 17 456 054 + 1;
- 17 456 054 ÷ 2 = 8 728 027 + 0;
- 8 728 027 ÷ 2 = 4 364 013 + 1;
- 4 364 013 ÷ 2 = 2 182 006 + 1;
- 2 182 006 ÷ 2 = 1 091 003 + 0;
- 1 091 003 ÷ 2 = 545 501 + 1;
- 545 501 ÷ 2 = 272 750 + 1;
- 272 750 ÷ 2 = 136 375 + 0;
- 136 375 ÷ 2 = 68 187 + 1;
- 68 187 ÷ 2 = 34 093 + 1;
- 34 093 ÷ 2 = 17 046 + 1;
- 17 046 ÷ 2 = 8 523 + 0;
- 8 523 ÷ 2 = 4 261 + 1;
- 4 261 ÷ 2 = 2 130 + 1;
- 2 130 ÷ 2 = 1 065 + 0;
- 1 065 ÷ 2 = 532 + 1;
- 532 ÷ 2 = 266 + 0;
- 266 ÷ 2 = 133 + 0;
- 133 ÷ 2 = 66 + 1;
- 66 ÷ 2 = 33 + 0;
- 33 ÷ 2 = 16 + 1;
- 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.
142 999 999 885(10) = 10 0001 0100 1011 0111 0110 1101 0101 1000 1101(2)
4. Determine the signed binary number bit length:
The base 2 number's actual length, in bits: 38.
- 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, 38,
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.
142 999 999 885(10) = 0000 0000 0000 0000 0000 0000 0010 0001 0100 1011 0111 0110 1101 0101 1000 1101
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 0010 0001 0100 1011 0111 0110 1101 0101 1000 1101)
= 1111 1111 1111 1111 1111 1111 1101 1110 1011 0100 1000 1001 0010 1010 0111 0010
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 1101 1110 1011 0100 1000 1001 0010 1010 0111 0010 (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):
-142 999 999 885 =
1111 1111 1111 1111 1111 1111 1101 1110 1011 0100 1000 1001 0010 1010 0111 0010 + 1
Decimal Number -142 999 999 885(10) converted to signed binary in two's complement representation:
-142 999 999 885(10) = 1111 1111 1111 1111 1111 1111 1101 1110 1011 0100 1000 1001 0010 1010 0111 0011
Spaces were used to group digits: for binary, by 4, for decimal, by 3.