How to convert a signed binary two's complement:
1111 1111 0111 1100(2)
to an integer in decimal system (in base 10)
1. Is this a positive or a negative number?
In a signed binary two's complement, first bit (the leftmost) indicates the sign,
1 = negative, 0 = positive.
1111 1111 0111 1100 is the binary representation of a negative integer, on 16 bits (2 Bytes).
2. Get the binary representation in one's complement:
* Run this step only if the number is negative *
Subtract 1 from the binary initial number:
1111 1111 0111 1100 - 1 = 1111 1111 0111 1011
3. Get the binary representation of the positive (unsigned) number:
* Run this step only if the number is negative *
Flip all the bits in the signed binary one's complement representation (reverse the digits) - replace the bits set on 1 with 0s and the bits on 0 with 1s:
!(1111 1111 0111 1011) = 0000 0000 1000 0100
4. Map the unsigned binary number's digits versus the corresponding powers of 2 that their place value represent:
215
0 214
0 213
0 212
0 211
0 210
0 29
0 28
0 27
1 26
0 25
0 24
0 23
0 22
1 21
0 20
0
5. Multiply each bit by its corresponding power of 2 and add all the terms up:
0000 0000 1000 0100(2) =
(0 × 215 + 0 × 214 + 0 × 213 + 0 × 212 + 0 × 211 + 0 × 210 + 0 × 29 + 0 × 28 + 1 × 27 + 0 × 26 + 0 × 25 + 0 × 24 + 0 × 23 + 1 × 22 + 0 × 21 + 0 × 20)(10) =
(0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 128 + 0 + 0 + 0 + 0 + 4 + 0 + 0)(10) =
(128 + 4)(10) =
132(10)
6. If needed, adjust the sign of the integer number by the first digit (leftmost) of the signed binary:
1111 1111 0111 1100(2) = -132(10)
Conclusion:
Number 1111 1111 0111 1100(2) converted from signed binary two's complement representation to an integer in decimal system (in base 10):
1111 1111 0111 1100(2) = -132(10)
Spaces used to group digits: for binary, by 4.
More operations of this kind:
Convert signed binary two's complement numbers to decimal system (base ten) integers
Entered binary number length must be: 2, 4, 8, 16, 32, or 64 - otherwise extra bits on 0 will be added in front (to the left).