What are the steps to convert the signed binary in two's (2's) complement representation to an integer in decimal system (in base ten)?
1. Is this a positive or a negative number?
0011 0110 0111 1001 0000 0111 0110 0100 0101 0011 0010 0100 0110 0111 1110 1000 is the binary representation of a positive integer, on 64 bits (8 Bytes).
- In a signed binary in two's complement representation, the first bit (the leftmost) indicates the sign, 1 = negative, 0 = positive.
2. Get the binary representation in one's complement.
* Run this step only if the number is negative
- Note on binary subtraction rules:
- 11 - 1 = 10; 10 - 1 = 01; 1 - 0 = 1; 1 - 1 = 0.
Subtract 1 from the initial binary number.
* Not the case - the number is positive
3. 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:
* Not the case - the number is positive
4. Map the unsigned binary number's digits versus the corresponding powers of 2 that their place value represent:
263
0 262
0 261
1 260
1 259
0 258
1 257
1 256
0 255
0 254
1 253
1 252
1 251
1 250
0 249
0 248
1 247
0 246
0 245
0 244
0 243
0 242
1 241
1 240
1 239
0 238
1 237
1 236
0 235
0 234
1 233
0 232
0 231
0 230
1 229
0 228
1 227
0 226
0 225
1 224
1 223
0 222
0 221
1 220
0 219
0 218
1 217
0 216
0 215
0 214
1 213
1 212
0 211
0 210
1 29
1 28
1 27
1 26
1 25
1 24
0 23
1 22
0 21
0 20
0
5. Multiply each bit by its corresponding power of 2 and add all the terms up.
0011 0110 0111 1001 0000 0111 0110 0100 0101 0011 0010 0100 0110 0111 1110 1000(2) =
(0 × 263 + 0 × 262 + 1 × 261 + 1 × 260 + 0 × 259 + 1 × 258 + 1 × 257 + 0 × 256 + 0 × 255 + 1 × 254 + 1 × 253 + 1 × 252 + 1 × 251 + 0 × 250 + 0 × 249 + 1 × 248 + 0 × 247 + 0 × 246 + 0 × 245 + 0 × 244 + 0 × 243 + 1 × 242 + 1 × 241 + 1 × 240 + 0 × 239 + 1 × 238 + 1 × 237 + 0 × 236 + 0 × 235 + 1 × 234 + 0 × 233 + 0 × 232 + 0 × 231 + 1 × 230 + 0 × 229 + 1 × 228 + 0 × 227 + 0 × 226 + 1 × 225 + 1 × 224 + 0 × 223 + 0 × 222 + 1 × 221 + 0 × 220 + 0 × 219 + 1 × 218 + 0 × 217 + 0 × 216 + 0 × 215 + 1 × 214 + 1 × 213 + 0 × 212 + 0 × 211 + 1 × 210 + 1 × 29 + 1 × 28 + 1 × 27 + 1 × 26 + 1 × 25 + 0 × 24 + 1 × 23 + 0 × 22 + 0 × 21 + 0 × 20)(10) =
(0 + 0 + 2 305 843 009 213 693 952 + 1 152 921 504 606 846 976 + 0 + 288 230 376 151 711 744 + 144 115 188 075 855 872 + 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 + 0 + 0 + 281 474 976 710 656 + 0 + 0 + 0 + 0 + 0 + 4 398 046 511 104 + 2 199 023 255 552 + 1 099 511 627 776 + 0 + 274 877 906 944 + 137 438 953 472 + 0 + 0 + 17 179 869 184 + 0 + 0 + 0 + 1 073 741 824 + 0 + 268 435 456 + 0 + 0 + 33 554 432 + 16 777 216 + 0 + 0 + 2 097 152 + 0 + 0 + 262 144 + 0 + 0 + 0 + 16 384 + 8 192 + 0 + 0 + 1 024 + 512 + 256 + 128 + 64 + 32 + 0 + 8 + 0 + 0 + 0)(10) =
(2 305 843 009 213 693 952 + 1 152 921 504 606 846 976 + 288 230 376 151 711 744 + 144 115 188 075 855 872 + 18 014 398 509 481 984 + 9 007 199 254 740 992 + 4 503 599 627 370 496 + 2 251 799 813 685 248 + 281 474 976 710 656 + 4 398 046 511 104 + 2 199 023 255 552 + 1 099 511 627 776 + 274 877 906 944 + 137 438 953 472 + 17 179 869 184 + 1 073 741 824 + 268 435 456 + 33 554 432 + 16 777 216 + 2 097 152 + 262 144 + 16 384 + 8 192 + 1 024 + 512 + 256 + 128 + 64 + 32 + 8)(10) =
3 925 176 677 703 116 776(10)
6. If needed, adjust the sign of the integer number by the first digit (leftmost) of the signed binary:
0011 0110 0111 1001 0000 0111 0110 0100 0101 0011 0010 0100 0110 0111 1110 1000(2) = 3 925 176 677 703 116 776(10)
The number 0011 0110 0111 1001 0000 0111 0110 0100 0101 0011 0010 0100 0110 0111 1110 1000(2), signed binary in two's (2's) complement representation, converted and written as an integer in decimal system (base ten):
0011 0110 0111 1001 0000 0111 0110 0100 0101 0011 0010 0100 0110 0111 1110 1000(2) = 3 925 176 677 703 116 776(10)
Spaces were used to group digits: for binary, by 4, for decimal, by 3.