What are the steps to convert the base 2 signed binary number
1100 0111 0101 1101 1011 1011 1010 1010 1101 0110 1011 1000 1000 1111 1011 0001(2) to a base 10 decimal system equivalent integer?
1. Is this a positive or a negative number?
1100 0111 0101 1101 1011 1011 1010 1010 1101 0110 1011 1000 1000 1111 1011 0001 is the binary representation of a negative integer, on 64 bits (8 Bytes).
- In a signed binary, the first bit (the leftmost) is reserved for the sign, 1 = negative, 0 = positive. This bit does not count when calculating the absolute value.
2. Construct the unsigned binary number.
Exclude the first bit (the leftmost), that is reserved for the sign:
1100 0111 0101 1101 1011 1011 1010 1010 1101 0110 1011 1000 1000 1111 1011 0001 = 100 0111 0101 1101 1011 1011 1010 1010 1101 0110 1011 1000 1000 1111 1011 0001
3. Map the unsigned binary number's digits versus the corresponding powers of 2 that their place value represent:
262
1 261
0 260
0 259
0 258
1 257
1 256
1 255
0 254
1 253
0 252
1 251
1 250
1 249
0 248
1 247
1 246
0 245
1 244
1 243
1 242
0 241
1 240
1 239
1 238
0 237
1 236
0 235
1 234
0 233
1 232
0 231
1 230
1 229
0 228
1 227
0 226
1 225
1 224
0 223
1 222
0 221
1 220
1 219
1 218
0 217
0 216
0 215
1 214
0 213
0 212
0 211
1 210
1 29
1 28
1 27
1 26
0 25
1 24
1 23
0 22
0 21
0 20
1
4. Multiply each bit by its corresponding power of 2 and add all the terms up.
100 0111 0101 1101 1011 1011 1010 1010 1101 0110 1011 1000 1000 1111 1011 0001(2) =
(1 × 262 + 0 × 261 + 0 × 260 + 0 × 259 + 1 × 258 + 1 × 257 + 1 × 256 + 0 × 255 + 1 × 254 + 0 × 253 + 1 × 252 + 1 × 251 + 1 × 250 + 0 × 249 + 1 × 248 + 1 × 247 + 0 × 246 + 1 × 245 + 1 × 244 + 1 × 243 + 0 × 242 + 1 × 241 + 1 × 240 + 1 × 239 + 0 × 238 + 1 × 237 + 0 × 236 + 1 × 235 + 0 × 234 + 1 × 233 + 0 × 232 + 1 × 231 + 1 × 230 + 0 × 229 + 1 × 228 + 0 × 227 + 1 × 226 + 1 × 225 + 0 × 224 + 1 × 223 + 0 × 222 + 1 × 221 + 1 × 220 + 1 × 219 + 0 × 218 + 0 × 217 + 0 × 216 + 1 × 215 + 0 × 214 + 0 × 213 + 0 × 212 + 1 × 211 + 1 × 210 + 1 × 29 + 1 × 28 + 1 × 27 + 0 × 26 + 1 × 25 + 1 × 24 + 0 × 23 + 0 × 22 + 0 × 21 + 1 × 20)(10) =
(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 + 0 + 18 014 398 509 481 984 + 0 + 4 503 599 627 370 496 + 2 251 799 813 685 248 + 1 125 899 906 842 624 + 0 + 281 474 976 710 656 + 140 737 488 355 328 + 0 + 35 184 372 088 832 + 17 592 186 044 416 + 8 796 093 022 208 + 0 + 2 199 023 255 552 + 1 099 511 627 776 + 549 755 813 888 + 0 + 137 438 953 472 + 0 + 34 359 738 368 + 0 + 8 589 934 592 + 0 + 2 147 483 648 + 1 073 741 824 + 0 + 268 435 456 + 0 + 67 108 864 + 33 554 432 + 0 + 8 388 608 + 0 + 2 097 152 + 1 048 576 + 524 288 + 0 + 0 + 0 + 32 768 + 0 + 0 + 0 + 2 048 + 1 024 + 512 + 256 + 128 + 0 + 32 + 16 + 0 + 0 + 0 + 1)(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 + 18 014 398 509 481 984 + 4 503 599 627 370 496 + 2 251 799 813 685 248 + 1 125 899 906 842 624 + 281 474 976 710 656 + 140 737 488 355 328 + 35 184 372 088 832 + 17 592 186 044 416 + 8 796 093 022 208 + 2 199 023 255 552 + 1 099 511 627 776 + 549 755 813 888 + 137 438 953 472 + 34 359 738 368 + 8 589 934 592 + 2 147 483 648 + 1 073 741 824 + 268 435 456 + 67 108 864 + 33 554 432 + 8 388 608 + 2 097 152 + 1 048 576 + 524 288 + 32 768 + 2 048 + 1 024 + 512 + 256 + 128 + 32 + 16 + 1)(10) =
5 142 472 691 948 228 529(10)
5. If needed, adjust the sign of the integer number by the first digit (leftmost) of the signed binary:
1100 0111 0101 1101 1011 1011 1010 1010 1101 0110 1011 1000 1000 1111 1011 0001(2) = -5 142 472 691 948 228 529(10)
1100 0111 0101 1101 1011 1011 1010 1010 1101 0110 1011 1000 1000 1111 1011 0001(2), Base 2 signed binary number, converted and written as a base 10 decimal system equivalent integer:
1100 0111 0101 1101 1011 1011 1010 1010 1101 0110 1011 1000 1000 1111 1011 0001(2) = -5 142 472 691 948 228 529(10)
Spaces were used to group digits: for binary, by 4, for decimal, by 3.