One's Complement Binary to Integer: 1011 0111 1000 0001 0100 1111 0100 1111 0111 1110 0111 1111 0111 1011 1000 0111: Convert and Write the Signed Binary Number in One's Complement Representation as a Decimal System Base Ten Integer

Signed binary in one's complement representation 1011 0111 1000 0001 0100 1111 0100 1111 0111 1110 0111 1111 0111 1011 1000 0111(2) converted to an integer in decimal system (in base ten)

1. Is this a positive or a negative number?

1011 0111 1000 0001 0100 1111 0100 1111 0111 1110 0111 1111 0111 1011 1000 0111 is the binary representation of a negative integer, on 64 bits (8 Bytes).


In a signed binary in one's complement representation, the first bit (the leftmost) indicates the sign, 1 = negative, 0 = positive.


2. Get the binary representation of the positive (unsigned) number.

* Run this step only if the number is negative *

Flip all the bits of the signed binary in one's complement representation (reverse the digits) - replace the bits set on 1 with 0s and the bits on 0 with 1s:

!(1011 0111 1000 0001 0100 1111 0100 1111 0111 1110 0111 1111 0111 1011 1000 0111) = 0100 1000 0111 1110 1011 0000 1011 0000 1000 0001 1000 0000 1000 0100 0111 1000


3. Map the unsigned binary number's digits versus the corresponding powers of 2 that their place value represent:

  • 263

    0
  • 262

    1
  • 261

    0
  • 260

    0
  • 259

    1
  • 258

    0
  • 257

    0
  • 256

    0
  • 255

    0
  • 254

    1
  • 253

    1
  • 252

    1
  • 251

    1
  • 250

    1
  • 249

    1
  • 248

    0
  • 247

    1
  • 246

    0
  • 245

    1
  • 244

    1
  • 243

    0
  • 242

    0
  • 241

    0
  • 240

    0
  • 239

    1
  • 238

    0
  • 237

    1
  • 236

    1
  • 235

    0
  • 234

    0
  • 233

    0
  • 232

    0
  • 231

    1
  • 230

    0
  • 229

    0
  • 228

    0
  • 227

    0
  • 226

    0
  • 225

    0
  • 224

    1
  • 223

    1
  • 222

    0
  • 221

    0
  • 220

    0
  • 219

    0
  • 218

    0
  • 217

    0
  • 216

    0
  • 215

    1
  • 214

    0
  • 213

    0
  • 212

    0
  • 211

    0
  • 210

    1
  • 29

    0
  • 28

    0
  • 27

    0
  • 26

    1
  • 25

    1
  • 24

    1
  • 23

    1
  • 22

    0
  • 21

    0
  • 20

    0

4. Multiply each bit by its corresponding power of 2 and add all the terms up.

0100 1000 0111 1110 1011 0000 1011 0000 1000 0001 1000 0000 1000 0100 0111 1000(2) =


(0 × 263 + 1 × 262 + 0 × 261 + 0 × 260 + 1 × 259 + 0 × 258 + 0 × 257 + 0 × 256 + 0 × 255 + 1 × 254 + 1 × 253 + 1 × 252 + 1 × 251 + 1 × 250 + 1 × 249 + 0 × 248 + 1 × 247 + 0 × 246 + 1 × 245 + 1 × 244 + 0 × 243 + 0 × 242 + 0 × 241 + 0 × 240 + 1 × 239 + 0 × 238 + 1 × 237 + 1 × 236 + 0 × 235 + 0 × 234 + 0 × 233 + 0 × 232 + 1 × 231 + 0 × 230 + 0 × 229 + 0 × 228 + 0 × 227 + 0 × 226 + 0 × 225 + 1 × 224 + 1 × 223 + 0 × 222 + 0 × 221 + 0 × 220 + 0 × 219 + 0 × 218 + 0 × 217 + 0 × 216 + 1 × 215 + 0 × 214 + 0 × 213 + 0 × 212 + 0 × 211 + 1 × 210 + 0 × 29 + 0 × 28 + 0 × 27 + 1 × 26 + 1 × 25 + 1 × 24 + 1 × 23 + 0 × 22 + 0 × 21 + 0 × 20)(10) =


(0 + 4 611 686 018 427 387 904 + 0 + 0 + 576 460 752 303 423 488 + 0 + 0 + 0 + 0 + 18 014 398 509 481 984 + 9 007 199 254 740 992 + 4 503 599 627 370 496 + 2 251 799 813 685 248 + 1 125 899 906 842 624 + 562 949 953 421 312 + 0 + 140 737 488 355 328 + 0 + 35 184 372 088 832 + 17 592 186 044 416 + 0 + 0 + 0 + 0 + 549 755 813 888 + 0 + 137 438 953 472 + 68 719 476 736 + 0 + 0 + 0 + 0 + 2 147 483 648 + 0 + 0 + 0 + 0 + 0 + 0 + 16 777 216 + 8 388 608 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 32 768 + 0 + 0 + 0 + 0 + 1 024 + 0 + 0 + 0 + 64 + 32 + 16 + 8 + 0 + 0 + 0)(10) =


(4 611 686 018 427 387 904 + 576 460 752 303 423 488 + 18 014 398 509 481 984 + 9 007 199 254 740 992 + 4 503 599 627 370 496 + 2 251 799 813 685 248 + 1 125 899 906 842 624 + 562 949 953 421 312 + 140 737 488 355 328 + 35 184 372 088 832 + 17 592 186 044 416 + 549 755 813 888 + 137 438 953 472 + 68 719 476 736 + 2 147 483 648 + 16 777 216 + 8 388 608 + 32 768 + 1 024 + 64 + 32 + 16 + 8)(10) =


5 223 806 889 929 770 104(10)

5. If needed, adjust the sign of the integer number by the first digit (leftmost) of the signed binary:

1011 0111 1000 0001 0100 1111 0100 1111 0111 1110 0111 1111 0111 1011 1000 0111(2) = -5 223 806 889 929 770 104(10)

The signed binary number in one's complement representation 1011 0111 1000 0001 0100 1111 0100 1111 0111 1110 0111 1111 0111 1011 1000 0111(2) converted and written as an integer in decimal system (base ten):
1011 0111 1000 0001 0100 1111 0100 1111 0111 1110 0111 1111 0111 1011 1000 0111(2) = -5 223 806 889 929 770 104(10)

Spaces were used to group digits: for binary, by 4, for decimal, by 3.

How to convert signed binary numbers in one's complement representation from binary system to decimal

To understand how to convert a signed binary number in one's complement representation from binary system to decimal (base ten), the easiest way is to do it through an example - convert binary, 1001 1101, to base ten:

  • In a signed binary one's complement, first bit (leftmost) indicates the sign, 1 = negative, 0 = positive. The first bit is 1, so our number is negative.
  • Get the binary representation of the positive number, flip all the bits in the signed binary one's complement representation (reversing the digits) - replace the bits set on 1 with 0s and the bits on 0 with 1s:
    !(1001 1101) = 0110 0010
  • Write bellow the positive binary number representation in base two, and above each bit that makes up the binary number write the corresponding power of 2 (numeral base) that its place value represents, starting with zero, from the right of the number (rightmost bit), walking to the left of the number by increasing each corresonding power of 2 by exactly one unit:
  • powers of 2: 7 6 5 4 3 2 1 0
    digits: 0 1 1 0 0 0 1 0
  • Build the representation of the positive number in base 10, by taking each digit of the binary number, multiplying it by the corresponding power of 2 and then adding all the terms up:

    0110 0010(2) =


    (0 × 27 + 1 × 26 + 1 × 25 + 0 × 24 + 0 × 23 + 0 × 22 + 1 × 21 + 0 × 20)(10) =


    (0 + 64 + 32 + 0 + 0 + 0 + 2 + 0)(10) =


    (64 + 32 + 2)(10) =


    98(10)

  • Signed binary number in one's complement representation, 1001 1110 = -98(10), a signed negative integer in base 10