What are the steps to convert the base 2 signed binary number
1000 0001 1111 0000 0010 0001 1111 0111(2) to a base 10 decimal system equivalent integer?
1. Is this a positive or a negative number?
1000 0001 1111 0000 0010 0001 1111 0111 is the binary representation of a negative integer, on 32 bits (4 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:
1000 0001 1111 0000 0010 0001 1111 0111 = 000 0001 1111 0000 0010 0001 1111 0111
3. Map the unsigned binary number's digits versus the corresponding powers of 2 that their place value represent:
230
0 229
0 228
0 227
0 226
0 225
0 224
1 223
1 222
1 221
1 220
1 219
0 218
0 217
0 216
0 215
0 214
0 213
1 212
0 211
0 210
0 29
0 28
1 27
1 26
1 25
1 24
1 23
0 22
1 21
1 20
1
4. Multiply each bit by its corresponding power of 2 and add all the terms up.
000 0001 1111 0000 0010 0001 1111 0111(2) =
(0 × 230 + 0 × 229 + 0 × 228 + 0 × 227 + 0 × 226 + 0 × 225 + 1 × 224 + 1 × 223 + 1 × 222 + 1 × 221 + 1 × 220 + 0 × 219 + 0 × 218 + 0 × 217 + 0 × 216 + 0 × 215 + 0 × 214 + 1 × 213 + 0 × 212 + 0 × 211 + 0 × 210 + 0 × 29 + 1 × 28 + 1 × 27 + 1 × 26 + 1 × 25 + 1 × 24 + 0 × 23 + 1 × 22 + 1 × 21 + 1 × 20)(10) =
(0 + 0 + 0 + 0 + 0 + 0 + 16 777 216 + 8 388 608 + 4 194 304 + 2 097 152 + 1 048 576 + 0 + 0 + 0 + 0 + 0 + 0 + 8 192 + 0 + 0 + 0 + 0 + 256 + 128 + 64 + 32 + 16 + 0 + 4 + 2 + 1)(10) =
(16 777 216 + 8 388 608 + 4 194 304 + 2 097 152 + 1 048 576 + 8 192 + 256 + 128 + 64 + 32 + 16 + 4 + 2 + 1)(10) =
32 514 551(10)
5. If needed, adjust the sign of the integer number by the first digit (leftmost) of the signed binary:
1000 0001 1111 0000 0010 0001 1111 0111(2) = -32 514 551(10)
1000 0001 1111 0000 0010 0001 1111 0111(2), Base 2 signed binary number, converted and written as a base 10 decimal system equivalent integer:
1000 0001 1111 0000 0010 0001 1111 0111(2) = -32 514 551(10)
Spaces were used to group digits: for binary, by 4, for decimal, by 3.