What are the steps to convert the base 2 signed binary number
1011 1110 1000 1000 1010 0001 1100 1100 1110 0111 1110 1111 0001 0001 0101 1110(2) to a base 10 decimal system equivalent integer?
1. Is this a positive or a negative number?
1011 1110 1000 1000 1010 0001 1100 1100 1110 0111 1110 1111 0001 0001 0101 1110 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:
1011 1110 1000 1000 1010 0001 1100 1100 1110 0111 1110 1111 0001 0001 0101 1110 = 011 1110 1000 1000 1010 0001 1100 1100 1110 0111 1110 1111 0001 0001 0101 1110
3. Map the unsigned binary number's digits versus the corresponding powers of 2 that their place value represent:
262
0 261
1 260
1 259
1 258
1 257
1 256
0 255
1 254
0 253
0 252
0 251
1 250
0 249
0 248
0 247
1 246
0 245
1 244
0 243
0 242
0 241
0 240
1 239
1 238
1 237
0 236
0 235
1 234
1 233
0 232
0 231
1 230
1 229
1 228
0 227
0 226
1 225
1 224
1 223
1 222
1 221
1 220
0 219
1 218
1 217
1 216
1 215
0 214
0 213
0 212
1 211
0 210
0 29
0 28
1 27
0 26
1 25
0 24
1 23
1 22
1 21
1 20
0
4. Multiply each bit by its corresponding power of 2 and add all the terms up.
011 1110 1000 1000 1010 0001 1100 1100 1110 0111 1110 1111 0001 0001 0101 1110(2) =
(0 × 262 + 1 × 261 + 1 × 260 + 1 × 259 + 1 × 258 + 1 × 257 + 0 × 256 + 1 × 255 + 0 × 254 + 0 × 253 + 0 × 252 + 1 × 251 + 0 × 250 + 0 × 249 + 0 × 248 + 1 × 247 + 0 × 246 + 1 × 245 + 0 × 244 + 0 × 243 + 0 × 242 + 0 × 241 + 1 × 240 + 1 × 239 + 1 × 238 + 0 × 237 + 0 × 236 + 1 × 235 + 1 × 234 + 0 × 233 + 0 × 232 + 1 × 231 + 1 × 230 + 1 × 229 + 0 × 228 + 0 × 227 + 1 × 226 + 1 × 225 + 1 × 224 + 1 × 223 + 1 × 222 + 1 × 221 + 0 × 220 + 1 × 219 + 1 × 218 + 1 × 217 + 1 × 216 + 0 × 215 + 0 × 214 + 0 × 213 + 1 × 212 + 0 × 211 + 0 × 210 + 0 × 29 + 1 × 28 + 0 × 27 + 1 × 26 + 0 × 25 + 1 × 24 + 1 × 23 + 1 × 22 + 1 × 21 + 0 × 20)(10) =
(0 + 2 305 843 009 213 693 952 + 1 152 921 504 606 846 976 + 576 460 752 303 423 488 + 288 230 376 151 711 744 + 144 115 188 075 855 872 + 0 + 36 028 797 018 963 968 + 0 + 0 + 0 + 2 251 799 813 685 248 + 0 + 0 + 0 + 140 737 488 355 328 + 0 + 35 184 372 088 832 + 0 + 0 + 0 + 0 + 1 099 511 627 776 + 549 755 813 888 + 274 877 906 944 + 0 + 0 + 34 359 738 368 + 17 179 869 184 + 0 + 0 + 2 147 483 648 + 1 073 741 824 + 536 870 912 + 0 + 0 + 67 108 864 + 33 554 432 + 16 777 216 + 8 388 608 + 4 194 304 + 2 097 152 + 0 + 524 288 + 262 144 + 131 072 + 65 536 + 0 + 0 + 0 + 4 096 + 0 + 0 + 0 + 256 + 0 + 64 + 0 + 16 + 8 + 4 + 2 + 0)(10) =
(2 305 843 009 213 693 952 + 1 152 921 504 606 846 976 + 576 460 752 303 423 488 + 288 230 376 151 711 744 + 144 115 188 075 855 872 + 36 028 797 018 963 968 + 2 251 799 813 685 248 + 140 737 488 355 328 + 35 184 372 088 832 + 1 099 511 627 776 + 549 755 813 888 + 274 877 906 944 + 34 359 738 368 + 17 179 869 184 + 2 147 483 648 + 1 073 741 824 + 536 870 912 + 67 108 864 + 33 554 432 + 16 777 216 + 8 388 608 + 4 194 304 + 2 097 152 + 524 288 + 262 144 + 131 072 + 65 536 + 4 096 + 256 + 64 + 16 + 8 + 4 + 2)(10) =
4 506 029 328 620 786 014(10)
5. If needed, adjust the sign of the integer number by the first digit (leftmost) of the signed binary:
1011 1110 1000 1000 1010 0001 1100 1100 1110 0111 1110 1111 0001 0001 0101 1110(2) = -4 506 029 328 620 786 014(10)
1011 1110 1000 1000 1010 0001 1100 1100 1110 0111 1110 1111 0001 0001 0101 1110(2), Base 2 signed binary number, converted and written as a base 10 decimal system equivalent integer:
1011 1110 1000 1000 1010 0001 1100 1100 1110 0111 1110 1111 0001 0001 0101 1110(2) = -4 506 029 328 620 786 014(10)
Spaces were used to group digits: for binary, by 4, for decimal, by 3.