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 0000 1010 1000 1101 0000 1100 1010 0100 0000 1101 1000 1100 1010 0111 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
0 255
1 254
0 253
1 252
0 251
1 250
0 249
0 248
0 247
1 246
1 245
0 244
1 243
0 242
0 241
0 240
0 239
1 238
1 237
0 236
0 235
1 234
0 233
1 232
0 231
0 230
1 229
0 228
0 227
0 226
0 225
0 224
0 223
1 222
1 221
0 220
1 219
1 218
0 217
0 216
0 215
1 214
1 213
0 212
0 211
1 210
0 29
1 28
0 27
0 26
1 25
1 24
1 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 0000 1010 1000 1101 0000 1100 1010 0100 0000 1101 1000 1100 1010 0111 0010(2) =
(0 × 263 + 0 × 262 + 0 × 261 + 0 × 260 + 0 × 259 + 0 × 258 + 0 × 257 + 0 × 256 + 1 × 255 + 0 × 254 + 1 × 253 + 0 × 252 + 1 × 251 + 0 × 250 + 0 × 249 + 0 × 248 + 1 × 247 + 1 × 246 + 0 × 245 + 1 × 244 + 0 × 243 + 0 × 242 + 0 × 241 + 0 × 240 + 1 × 239 + 1 × 238 + 0 × 237 + 0 × 236 + 1 × 235 + 0 × 234 + 1 × 233 + 0 × 232 + 0 × 231 + 1 × 230 + 0 × 229 + 0 × 228 + 0 × 227 + 0 × 226 + 0 × 225 + 0 × 224 + 1 × 223 + 1 × 222 + 0 × 221 + 1 × 220 + 1 × 219 + 0 × 218 + 0 × 217 + 0 × 216 + 1 × 215 + 1 × 214 + 0 × 213 + 0 × 212 + 1 × 211 + 0 × 210 + 1 × 29 + 0 × 28 + 0 × 27 + 1 × 26 + 1 × 25 + 1 × 24 + 0 × 23 + 0 × 22 + 1 × 21 + 0 × 20)(10) =
(0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 36 028 797 018 963 968 + 0 + 9 007 199 254 740 992 + 0 + 2 251 799 813 685 248 + 0 + 0 + 0 + 140 737 488 355 328 + 70 368 744 177 664 + 0 + 17 592 186 044 416 + 0 + 0 + 0 + 0 + 549 755 813 888 + 274 877 906 944 + 0 + 0 + 34 359 738 368 + 0 + 8 589 934 592 + 0 + 0 + 1 073 741 824 + 0 + 0 + 0 + 0 + 0 + 0 + 8 388 608 + 4 194 304 + 0 + 1 048 576 + 524 288 + 0 + 0 + 0 + 32 768 + 16 384 + 0 + 0 + 2 048 + 0 + 512 + 0 + 0 + 64 + 32 + 16 + 0 + 0 + 2 + 0)(10) =
(36 028 797 018 963 968 + 9 007 199 254 740 992 + 2 251 799 813 685 248 + 140 737 488 355 328 + 70 368 744 177 664 + 17 592 186 044 416 + 549 755 813 888 + 274 877 906 944 + 34 359 738 368 + 8 589 934 592 + 1 073 741 824 + 8 388 608 + 4 194 304 + 1 048 576 + 524 288 + 32 768 + 16 384 + 2 048 + 512 + 64 + 32 + 16 + 2)(10) =
47 517 363 177 310 834(10)
6. If needed, adjust the sign of the integer number by the first digit (leftmost) of the signed binary:
0000 0000 1010 1000 1101 0000 1100 1010 0100 0000 1101 1000 1100 1010 0111 0010(2) = 47 517 363 177 310 834(10)
The number 0000 0000 1010 1000 1101 0000 1100 1010 0100 0000 1101 1000 1100 1010 0111 0010(2), signed binary in two's (2's) complement representation, converted and written as an integer in decimal system (base ten):
0000 0000 1010 1000 1101 0000 1100 1010 0100 0000 1101 1000 1100 1010 0111 0010(2) = 47 517 363 177 310 834(10)
Spaces were used to group digits: for binary, by 4, for decimal, by 3.