What are the steps to convert the base 2 signed binary number
1101 1000 1010 0111 1101 1000 1011 0011 1101 1000 1010 1010 1101 1000 0110 0111(2) to a base 10 decimal system equivalent integer?
1. Is this a positive or a negative number?
1101 1000 1010 0111 1101 1000 1011 0011 1101 1000 1010 1010 1101 1000 0110 0111 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:
1101 1000 1010 0111 1101 1000 1011 0011 1101 1000 1010 1010 1101 1000 0110 0111 = 101 1000 1010 0111 1101 1000 1011 0011 1101 1000 1010 1010 1101 1000 0110 0111
3. Map the unsigned binary number's digits versus the corresponding powers of 2 that their place value represent:
262
1 261
0 260
1 259
1 258
0 257
0 256
0 255
1 254
0 253
1 252
0 251
0 250
1 249
1 248
1 247
1 246
1 245
0 244
1 243
1 242
0 241
0 240
0 239
1 238
0 237
1 236
1 235
0 234
0 233
1 232
1 231
1 230
1 229
0 228
1 227
1 226
0 225
0 224
0 223
1 222
0 221
1 220
0 219
1 218
0 217
1 216
0 215
1 214
1 213
0 212
1 211
1 210
0 29
0 28
0 27
0 26
1 25
1 24
0 23
0 22
1 21
1 20
1
4. Multiply each bit by its corresponding power of 2 and add all the terms up.
101 1000 1010 0111 1101 1000 1011 0011 1101 1000 1010 1010 1101 1000 0110 0111(2) =
(1 × 262 + 0 × 261 + 1 × 260 + 1 × 259 + 0 × 258 + 0 × 257 + 0 × 256 + 1 × 255 + 0 × 254 + 1 × 253 + 0 × 252 + 0 × 251 + 1 × 250 + 1 × 249 + 1 × 248 + 1 × 247 + 1 × 246 + 0 × 245 + 1 × 244 + 1 × 243 + 0 × 242 + 0 × 241 + 0 × 240 + 1 × 239 + 0 × 238 + 1 × 237 + 1 × 236 + 0 × 235 + 0 × 234 + 1 × 233 + 1 × 232 + 1 × 231 + 1 × 230 + 0 × 229 + 1 × 228 + 1 × 227 + 0 × 226 + 0 × 225 + 0 × 224 + 1 × 223 + 0 × 222 + 1 × 221 + 0 × 220 + 1 × 219 + 0 × 218 + 1 × 217 + 0 × 216 + 1 × 215 + 1 × 214 + 0 × 213 + 1 × 212 + 1 × 211 + 0 × 210 + 0 × 29 + 0 × 28 + 0 × 27 + 1 × 26 + 1 × 25 + 0 × 24 + 0 × 23 + 1 × 22 + 1 × 21 + 1 × 20)(10) =
(4 611 686 018 427 387 904 + 0 + 1 152 921 504 606 846 976 + 576 460 752 303 423 488 + 0 + 0 + 0 + 36 028 797 018 963 968 + 0 + 9 007 199 254 740 992 + 0 + 0 + 1 125 899 906 842 624 + 562 949 953 421 312 + 281 474 976 710 656 + 140 737 488 355 328 + 70 368 744 177 664 + 0 + 17 592 186 044 416 + 8 796 093 022 208 + 0 + 0 + 0 + 549 755 813 888 + 0 + 137 438 953 472 + 68 719 476 736 + 0 + 0 + 8 589 934 592 + 4 294 967 296 + 2 147 483 648 + 1 073 741 824 + 0 + 268 435 456 + 134 217 728 + 0 + 0 + 0 + 8 388 608 + 0 + 2 097 152 + 0 + 524 288 + 0 + 131 072 + 0 + 32 768 + 16 384 + 0 + 4 096 + 2 048 + 0 + 0 + 0 + 0 + 64 + 32 + 0 + 0 + 4 + 2 + 1)(10) =
(4 611 686 018 427 387 904 + 1 152 921 504 606 846 976 + 576 460 752 303 423 488 + 36 028 797 018 963 968 + 9 007 199 254 740 992 + 1 125 899 906 842 624 + 562 949 953 421 312 + 281 474 976 710 656 + 140 737 488 355 328 + 70 368 744 177 664 + 17 592 186 044 416 + 8 796 093 022 208 + 549 755 813 888 + 137 438 953 472 + 68 719 476 736 + 8 589 934 592 + 4 294 967 296 + 2 147 483 648 + 1 073 741 824 + 268 435 456 + 134 217 728 + 8 388 608 + 2 097 152 + 524 288 + 131 072 + 32 768 + 16 384 + 4 096 + 2 048 + 64 + 32 + 4 + 2 + 1)(10) =
6 388 312 863 394 158 695(10)
5. If needed, adjust the sign of the integer number by the first digit (leftmost) of the signed binary:
1101 1000 1010 0111 1101 1000 1011 0011 1101 1000 1010 1010 1101 1000 0110 0111(2) = -6 388 312 863 394 158 695(10)
1101 1000 1010 0111 1101 1000 1011 0011 1101 1000 1010 1010 1101 1000 0110 0111(2), Base 2 signed binary number, converted and written as a base 10 decimal system equivalent integer:
1101 1000 1010 0111 1101 1000 1011 0011 1101 1000 1010 1010 1101 1000 0110 0111(2) = -6 388 312 863 394 158 695(10)
Spaces were used to group digits: for binary, by 4, for decimal, by 3.