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?
0100 0111 1100 0010 0000 1011 0000 1110 1111 1111 1111 1111 1111 1111 1110 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
1 261
0 260
0 259
0 258
1 257
1 256
1 255
1 254
1 253
0 252
0 251
0 250
0 249
1 248
0 247
0 246
0 245
0 244
0 243
1 242
0 241
1 240
1 239
0 238
0 237
0 236
0 235
1 234
1 233
1 232
0 231
1 230
1 229
1 228
1 227
1 226
1 225
1 224
1 223
1 222
1 221
1 220
1 219
1 218
1 217
1 216
1 215
1 214
1 213
1 212
1 211
1 210
1 29
1 28
1 27
1 26
1 25
1 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.
0100 0111 1100 0010 0000 1011 0000 1110 1111 1111 1111 1111 1111 1111 1110 0010(2) =
(0 × 263 + 1 × 262 + 0 × 261 + 0 × 260 + 0 × 259 + 1 × 258 + 1 × 257 + 1 × 256 + 1 × 255 + 1 × 254 + 0 × 253 + 0 × 252 + 0 × 251 + 0 × 250 + 1 × 249 + 0 × 248 + 0 × 247 + 0 × 246 + 0 × 245 + 0 × 244 + 1 × 243 + 0 × 242 + 1 × 241 + 1 × 240 + 0 × 239 + 0 × 238 + 0 × 237 + 0 × 236 + 1 × 235 + 1 × 234 + 1 × 233 + 0 × 232 + 1 × 231 + 1 × 230 + 1 × 229 + 1 × 228 + 1 × 227 + 1 × 226 + 1 × 225 + 1 × 224 + 1 × 223 + 1 × 222 + 1 × 221 + 1 × 220 + 1 × 219 + 1 × 218 + 1 × 217 + 1 × 216 + 1 × 215 + 1 × 214 + 1 × 213 + 1 × 212 + 1 × 211 + 1 × 210 + 1 × 29 + 1 × 28 + 1 × 27 + 1 × 26 + 1 × 25 + 0 × 24 + 0 × 23 + 0 × 22 + 1 × 21 + 0 × 20)(10) =
(0 + 4 611 686 018 427 387 904 + 0 + 0 + 0 + 288 230 376 151 711 744 + 144 115 188 075 855 872 + 72 057 594 037 927 936 + 36 028 797 018 963 968 + 18 014 398 509 481 984 + 0 + 0 + 0 + 0 + 562 949 953 421 312 + 0 + 0 + 0 + 0 + 0 + 8 796 093 022 208 + 0 + 2 199 023 255 552 + 1 099 511 627 776 + 0 + 0 + 0 + 0 + 34 359 738 368 + 17 179 869 184 + 8 589 934 592 + 0 + 2 147 483 648 + 1 073 741 824 + 536 870 912 + 268 435 456 + 134 217 728 + 67 108 864 + 33 554 432 + 16 777 216 + 8 388 608 + 4 194 304 + 2 097 152 + 1 048 576 + 524 288 + 262 144 + 131 072 + 65 536 + 32 768 + 16 384 + 8 192 + 4 096 + 2 048 + 1 024 + 512 + 256 + 128 + 64 + 32 + 0 + 0 + 0 + 2 + 0)(10) =
(4 611 686 018 427 387 904 + 288 230 376 151 711 744 + 144 115 188 075 855 872 + 72 057 594 037 927 936 + 36 028 797 018 963 968 + 18 014 398 509 481 984 + 562 949 953 421 312 + 8 796 093 022 208 + 2 199 023 255 552 + 1 099 511 627 776 + 34 359 738 368 + 17 179 869 184 + 8 589 934 592 + 2 147 483 648 + 1 073 741 824 + 536 870 912 + 268 435 456 + 134 217 728 + 67 108 864 + 33 554 432 + 16 777 216 + 8 388 608 + 4 194 304 + 2 097 152 + 1 048 576 + 524 288 + 262 144 + 131 072 + 65 536 + 32 768 + 16 384 + 8 192 + 4 096 + 2 048 + 1 024 + 512 + 256 + 128 + 64 + 32 + 2)(10) =
5 170 707 481 227 165 666(10)
6. If needed, adjust the sign of the integer number by the first digit (leftmost) of the signed binary:
0100 0111 1100 0010 0000 1011 0000 1110 1111 1111 1111 1111 1111 1111 1110 0010(2) = 5 170 707 481 227 165 666(10)
The number 0100 0111 1100 0010 0000 1011 0000 1110 1111 1111 1111 1111 1111 1111 1110 0010(2), signed binary in two's (2's) complement representation, converted and written as an integer in decimal system (base ten):
0100 0111 1100 0010 0000 1011 0000 1110 1111 1111 1111 1111 1111 1111 1110 0010(2) = 5 170 707 481 227 165 666(10)
Spaces were used to group digits: for binary, by 4, for decimal, by 3.