1. Is this a positive or a negative number?
1001 1010 0110 1001 1010 0110 1001 1010 0110 1001 1010 0110 1001 1010 0011 1011 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:
!(1001 1010 0110 1001 1010 0110 1001 1010 0110 1001 1010 0110 1001 1010 0011 1011) = 0110 0101 1001 0110 0101 1001 0110 0101 1001 0110 0101 1001 0110 0101 1100 0100
3. Map the unsigned binary number's digits versus the corresponding powers of 2 that their place value represent:
263
0 262
1 261
1 260
0 259
0 258
1 257
0 256
1 255
1 254
0 253
0 252
1 251
0 250
1 249
1 248
0 247
0 246
1 245
0 244
1 243
1 242
0 241
0 240
1 239
0 238
1 237
1 236
0 235
0 234
1 233
0 232
1 231
1 230
0 229
0 228
1 227
0 226
1 225
1 224
0 223
0 222
1 221
0 220
1 219
1 218
0 217
0 216
1 215
0 214
1 213
1 212
0 211
0 210
1 29
0 28
1 27
1 26
1 25
0 24
0 23
0 22
1 21
0 20
0
4. Multiply each bit by its corresponding power of 2 and add all the terms up.
0110 0101 1001 0110 0101 1001 0110 0101 1001 0110 0101 1001 0110 0101 1100 0100(2) =
(0 × 263 + 1 × 262 + 1 × 261 + 0 × 260 + 0 × 259 + 1 × 258 + 0 × 257 + 1 × 256 + 1 × 255 + 0 × 254 + 0 × 253 + 1 × 252 + 0 × 251 + 1 × 250 + 1 × 249 + 0 × 248 + 0 × 247 + 1 × 246 + 0 × 245 + 1 × 244 + 1 × 243 + 0 × 242 + 0 × 241 + 1 × 240 + 0 × 239 + 1 × 238 + 1 × 237 + 0 × 236 + 0 × 235 + 1 × 234 + 0 × 233 + 1 × 232 + 1 × 231 + 0 × 230 + 0 × 229 + 1 × 228 + 0 × 227 + 1 × 226 + 1 × 225 + 0 × 224 + 0 × 223 + 1 × 222 + 0 × 221 + 1 × 220 + 1 × 219 + 0 × 218 + 0 × 217 + 1 × 216 + 0 × 215 + 1 × 214 + 1 × 213 + 0 × 212 + 0 × 211 + 1 × 210 + 0 × 29 + 1 × 28 + 1 × 27 + 1 × 26 + 0 × 25 + 0 × 24 + 0 × 23 + 1 × 22 + 0 × 21 + 0 × 20)(10) =
(0 + 4 611 686 018 427 387 904 + 2 305 843 009 213 693 952 + 0 + 0 + 288 230 376 151 711 744 + 0 + 72 057 594 037 927 936 + 36 028 797 018 963 968 + 0 + 0 + 4 503 599 627 370 496 + 0 + 1 125 899 906 842 624 + 562 949 953 421 312 + 0 + 0 + 70 368 744 177 664 + 0 + 17 592 186 044 416 + 8 796 093 022 208 + 0 + 0 + 1 099 511 627 776 + 0 + 274 877 906 944 + 137 438 953 472 + 0 + 0 + 17 179 869 184 + 0 + 4 294 967 296 + 2 147 483 648 + 0 + 0 + 268 435 456 + 0 + 67 108 864 + 33 554 432 + 0 + 0 + 4 194 304 + 0 + 1 048 576 + 524 288 + 0 + 0 + 65 536 + 0 + 16 384 + 8 192 + 0 + 0 + 1 024 + 0 + 256 + 128 + 64 + 0 + 0 + 0 + 4 + 0 + 0)(10) =
(4 611 686 018 427 387 904 + 2 305 843 009 213 693 952 + 288 230 376 151 711 744 + 72 057 594 037 927 936 + 36 028 797 018 963 968 + 4 503 599 627 370 496 + 1 125 899 906 842 624 + 562 949 953 421 312 + 70 368 744 177 664 + 17 592 186 044 416 + 8 796 093 022 208 + 1 099 511 627 776 + 274 877 906 944 + 137 438 953 472 + 17 179 869 184 + 4 294 967 296 + 2 147 483 648 + 268 435 456 + 67 108 864 + 33 554 432 + 4 194 304 + 1 048 576 + 524 288 + 65 536 + 16 384 + 8 192 + 1 024 + 256 + 128 + 64 + 4)(10) =
7 320 136 537 186 330 052(10)
5. If needed, adjust the sign of the integer number by the first digit (leftmost) of the signed binary:
1001 1010 0110 1001 1010 0110 1001 1010 0110 1001 1010 0110 1001 1010 0011 1011(2) = -7 320 136 537 186 330 052(10)
The signed binary number in one's complement representation 1001 1010 0110 1001 1010 0110 1001 1010 0110 1001 1010 0110 1001 1010 0011 1011(2) converted and written as an integer in decimal system (base ten):
1001 1010 0110 1001 1010 0110 1001 1010 0110 1001 1010 0110 1001 1010 0011 1011(2) = -7 320 136 537 186 330 052(10)
Spaces were used to group digits: for binary, by 4, for decimal, by 3.