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?
0001 0000 0000 0010 0100 0111 1010 1110 0001 0100 0111 1010 1110 0001 0100 1101 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
0 260
1 259
0 258
0 257
0 256
0 255
0 254
0 253
0 252
0 251
0 250
0 249
1 248
0 247
0 246
1 245
0 244
0 243
0 242
1 241
1 240
1 239
1 238
0 237
1 236
0 235
1 234
1 233
1 232
0 231
0 230
0 229
0 228
1 227
0 226
1 225
0 224
0 223
0 222
1 221
1 220
1 219
1 218
0 217
1 216
0 215
1 214
1 213
1 212
0 211
0 210
0 29
0 28
1 27
0 26
1 25
0 24
0 23
1 22
1 21
0 20
1
5. Multiply each bit by its corresponding power of 2 and add all the terms up.
0001 0000 0000 0010 0100 0111 1010 1110 0001 0100 0111 1010 1110 0001 0100 1101(2) =
(0 × 263 + 0 × 262 + 0 × 261 + 1 × 260 + 0 × 259 + 0 × 258 + 0 × 257 + 0 × 256 + 0 × 255 + 0 × 254 + 0 × 253 + 0 × 252 + 0 × 251 + 0 × 250 + 1 × 249 + 0 × 248 + 0 × 247 + 1 × 246 + 0 × 245 + 0 × 244 + 0 × 243 + 1 × 242 + 1 × 241 + 1 × 240 + 1 × 239 + 0 × 238 + 1 × 237 + 0 × 236 + 1 × 235 + 1 × 234 + 1 × 233 + 0 × 232 + 0 × 231 + 0 × 230 + 0 × 229 + 1 × 228 + 0 × 227 + 1 × 226 + 0 × 225 + 0 × 224 + 0 × 223 + 1 × 222 + 1 × 221 + 1 × 220 + 1 × 219 + 0 × 218 + 1 × 217 + 0 × 216 + 1 × 215 + 1 × 214 + 1 × 213 + 0 × 212 + 0 × 211 + 0 × 210 + 0 × 29 + 1 × 28 + 0 × 27 + 1 × 26 + 0 × 25 + 0 × 24 + 1 × 23 + 1 × 22 + 0 × 21 + 1 × 20)(10) =
(0 + 0 + 0 + 1 152 921 504 606 846 976 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 562 949 953 421 312 + 0 + 0 + 70 368 744 177 664 + 0 + 0 + 0 + 4 398 046 511 104 + 2 199 023 255 552 + 1 099 511 627 776 + 549 755 813 888 + 0 + 137 438 953 472 + 0 + 34 359 738 368 + 17 179 869 184 + 8 589 934 592 + 0 + 0 + 0 + 0 + 268 435 456 + 0 + 67 108 864 + 0 + 0 + 0 + 4 194 304 + 2 097 152 + 1 048 576 + 524 288 + 0 + 131 072 + 0 + 32 768 + 16 384 + 8 192 + 0 + 0 + 0 + 0 + 256 + 0 + 64 + 0 + 0 + 8 + 4 + 0 + 1)(10) =
(1 152 921 504 606 846 976 + 562 949 953 421 312 + 70 368 744 177 664 + 4 398 046 511 104 + 2 199 023 255 552 + 1 099 511 627 776 + 549 755 813 888 + 137 438 953 472 + 34 359 738 368 + 17 179 869 184 + 8 589 934 592 + 268 435 456 + 67 108 864 + 4 194 304 + 2 097 152 + 1 048 576 + 524 288 + 131 072 + 32 768 + 16 384 + 8 192 + 256 + 64 + 8 + 4 + 1)(10) =
1 153 563 267 553 747 277(10)
6. If needed, adjust the sign of the integer number by the first digit (leftmost) of the signed binary:
0001 0000 0000 0010 0100 0111 1010 1110 0001 0100 0111 1010 1110 0001 0100 1101(2) = 1 153 563 267 553 747 277(10)
The number 0001 0000 0000 0010 0100 0111 1010 1110 0001 0100 0111 1010 1110 0001 0100 1101(2), signed binary in two's (2's) complement representation, converted and written as an integer in decimal system (base ten):
0001 0000 0000 0010 0100 0111 1010 1110 0001 0100 0111 1010 1110 0001 0100 1101(2) = 1 153 563 267 553 747 277(10)
Spaces were used to group digits: for binary, by 4, for decimal, by 3.