One's Complement: Binary ↘ Integer: 1111 0101 0001 0100 1011 0110 0011 1011 0000 1011 0100 1100 1111 0001 1111 0101 Signed Binary Number in One's Complement Representation, Converted and Written as a Decimal System Integer (in Base Ten)

Signed binary in one's complement representation 1111 0101 0001 0100 1011 0110 0011 1011 0000 1011 0100 1100 1111 0001 1111 0101(2) converted to an integer in decimal system (in base ten) = ?

1. Is this a positive or a negative number?

1111 0101 0001 0100 1011 0110 0011 1011 0000 1011 0100 1100 1111 0001 1111 0101 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:

!(1111 0101 0001 0100 1011 0110 0011 1011 0000 1011 0100 1100 1111 0001 1111 0101) = 0000 1010 1110 1011 0100 1001 1100 0100 1111 0100 1011 0011 0000 1110 0000 1010


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

  • 263

    0
  • 262

    0
  • 261

    0
  • 260

    0
  • 259

    1
  • 258

    0
  • 257

    1
  • 256

    0
  • 255

    1
  • 254

    1
  • 253

    1
  • 252

    0
  • 251

    1
  • 250

    0
  • 249

    1
  • 248

    1
  • 247

    0
  • 246

    1
  • 245

    0
  • 244

    0
  • 243

    1
  • 242

    0
  • 241

    0
  • 240

    1
  • 239

    1
  • 238

    1
  • 237

    0
  • 236

    0
  • 235

    0
  • 234

    1
  • 233

    0
  • 232

    0
  • 231

    1
  • 230

    1
  • 229

    1
  • 228

    1
  • 227

    0
  • 226

    1
  • 225

    0
  • 224

    0
  • 223

    1
  • 222

    0
  • 221

    1
  • 220

    1
  • 219

    0
  • 218

    0
  • 217

    1
  • 216

    1
  • 215

    0
  • 214

    0
  • 213

    0
  • 212

    0
  • 211

    1
  • 210

    1
  • 29

    1
  • 28

    0
  • 27

    0
  • 26

    0
  • 25

    0
  • 24

    0
  • 23

    1
  • 22

    0
  • 21

    1
  • 20

    0

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

0000 1010 1110 1011 0100 1001 1100 0100 1111 0100 1011 0011 0000 1110 0000 1010(2) =


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


(0 + 0 + 0 + 0 + 576 460 752 303 423 488 + 0 + 144 115 188 075 855 872 + 0 + 36 028 797 018 963 968 + 18 014 398 509 481 984 + 9 007 199 254 740 992 + 0 + 2 251 799 813 685 248 + 0 + 562 949 953 421 312 + 281 474 976 710 656 + 0 + 70 368 744 177 664 + 0 + 0 + 8 796 093 022 208 + 0 + 0 + 1 099 511 627 776 + 549 755 813 888 + 274 877 906 944 + 0 + 0 + 0 + 17 179 869 184 + 0 + 0 + 2 147 483 648 + 1 073 741 824 + 536 870 912 + 268 435 456 + 0 + 67 108 864 + 0 + 0 + 8 388 608 + 0 + 2 097 152 + 1 048 576 + 0 + 0 + 131 072 + 65 536 + 0 + 0 + 0 + 0 + 2 048 + 1 024 + 512 + 0 + 0 + 0 + 0 + 0 + 8 + 0 + 2 + 0)(10) =


(576 460 752 303 423 488 + 144 115 188 075 855 872 + 36 028 797 018 963 968 + 18 014 398 509 481 984 + 9 007 199 254 740 992 + 2 251 799 813 685 248 + 562 949 953 421 312 + 281 474 976 710 656 + 70 368 744 177 664 + 8 796 093 022 208 + 1 099 511 627 776 + 549 755 813 888 + 274 877 906 944 + 17 179 869 184 + 2 147 483 648 + 1 073 741 824 + 536 870 912 + 268 435 456 + 67 108 864 + 8 388 608 + 2 097 152 + 1 048 576 + 131 072 + 65 536 + 2 048 + 1 024 + 512 + 8 + 2)(10) =


786 803 670 174 076 426(10)

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

1111 0101 0001 0100 1011 0110 0011 1011 0000 1011 0100 1100 1111 0001 1111 0101(2) = -786 803 670 174 076 426(10)

The signed binary number in one's complement representation 1111 0101 0001 0100 1011 0110 0011 1011 0000 1011 0100 1100 1111 0001 1111 0101(2) converted and written as an integer in decimal system (base ten):
1111 0101 0001 0100 1011 0110 0011 1011 0000 1011 0100 1100 1111 0001 1111 0101(2) = -786 803 670 174 076 426(10)

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

The latest binary numbers in one's complement representation converted to signed integers numbers written in decimal system (base ten)

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