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?
0000 0001 0111 0011 0001 0111 0001 1101 0001 1001 1100 0001 0010 1001 1000 0010 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
0 259
0 258
0 257
0 256
1 255
0 254
1 253
1 252
1 251
0 250
0 249
1 248
1 247
0 246
0 245
0 244
1 243
0 242
1 241
1 240
1 239
0 238
0 237
0 236
1 235
1 234
1 233
0 232
1 231
0 230
0 229
0 228
1 227
1 226
0 225
0 224
1 223
1 222
1 221
0 220
0 219
0 218
0 217
0 216
1 215
0 214
0 213
1 212
0 211
1 210
0 29
0 28
1 27
1 26
0 25
0 24
0 23
0 22
0 21
1 20
0
5. Multiply each bit by its corresponding power of 2 and add all the terms up.
0000 0001 0111 0011 0001 0111 0001 1101 0001 1001 1100 0001 0010 1001 1000 0010(2) =
(0 × 263 + 0 × 262 + 0 × 261 + 0 × 260 + 0 × 259 + 0 × 258 + 0 × 257 + 1 × 256 + 0 × 255 + 1 × 254 + 1 × 253 + 1 × 252 + 0 × 251 + 0 × 250 + 1 × 249 + 1 × 248 + 0 × 247 + 0 × 246 + 0 × 245 + 1 × 244 + 0 × 243 + 1 × 242 + 1 × 241 + 1 × 240 + 0 × 239 + 0 × 238 + 0 × 237 + 1 × 236 + 1 × 235 + 1 × 234 + 0 × 233 + 1 × 232 + 0 × 231 + 0 × 230 + 0 × 229 + 1 × 228 + 1 × 227 + 0 × 226 + 0 × 225 + 1 × 224 + 1 × 223 + 1 × 222 + 0 × 221 + 0 × 220 + 0 × 219 + 0 × 218 + 0 × 217 + 1 × 216 + 0 × 215 + 0 × 214 + 1 × 213 + 0 × 212 + 1 × 211 + 0 × 210 + 0 × 29 + 1 × 28 + 1 × 27 + 0 × 26 + 0 × 25 + 0 × 24 + 0 × 23 + 0 × 22 + 1 × 21 + 0 × 20)(10) =
(0 + 0 + 0 + 0 + 0 + 0 + 0 + 72 057 594 037 927 936 + 0 + 18 014 398 509 481 984 + 9 007 199 254 740 992 + 4 503 599 627 370 496 + 0 + 0 + 562 949 953 421 312 + 281 474 976 710 656 + 0 + 0 + 0 + 17 592 186 044 416 + 0 + 4 398 046 511 104 + 2 199 023 255 552 + 1 099 511 627 776 + 0 + 0 + 0 + 68 719 476 736 + 34 359 738 368 + 17 179 869 184 + 0 + 4 294 967 296 + 0 + 0 + 0 + 268 435 456 + 134 217 728 + 0 + 0 + 16 777 216 + 8 388 608 + 4 194 304 + 0 + 0 + 0 + 0 + 0 + 65 536 + 0 + 0 + 8 192 + 0 + 2 048 + 0 + 0 + 256 + 128 + 0 + 0 + 0 + 0 + 0 + 2 + 0)(10) =
(72 057 594 037 927 936 + 18 014 398 509 481 984 + 9 007 199 254 740 992 + 4 503 599 627 370 496 + 562 949 953 421 312 + 281 474 976 710 656 + 17 592 186 044 416 + 4 398 046 511 104 + 2 199 023 255 552 + 1 099 511 627 776 + 68 719 476 736 + 34 359 738 368 + 17 179 869 184 + 4 294 967 296 + 268 435 456 + 134 217 728 + 16 777 216 + 8 388 608 + 4 194 304 + 65 536 + 8 192 + 2 048 + 256 + 128 + 2)(10) =
104 452 630 113 233 282(10)
6. If needed, adjust the sign of the integer number by the first digit (leftmost) of the signed binary:
0000 0001 0111 0011 0001 0111 0001 1101 0001 1001 1100 0001 0010 1001 1000 0010(2) = 104 452 630 113 233 282(10)
The number 0000 0001 0111 0011 0001 0111 0001 1101 0001 1001 1100 0001 0010 1001 1000 0010(2), signed binary in two's (2's) complement representation, converted and written as an integer in decimal system (base ten):
0000 0001 0111 0011 0001 0111 0001 1101 0001 1001 1100 0001 0010 1001 1000 0010(2) = 104 452 630 113 233 282(10)
Spaces were used to group digits: for binary, by 4, for decimal, by 3.