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?
0101 1111 0110 0100 0101 1101 0100 1010 is the binary representation of a positive integer, on 32 bits (4 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:
231
0 230
1 229
0 228
1 227
1 226
1 225
1 224
1 223
0 222
1 221
1 220
0 219
0 218
1 217
0 216
0 215
0 214
1 213
0 212
1 211
1 210
1 29
0 28
1 27
0 26
1 25
0 24
0 23
1 22
0 21
1 20
0
5. Multiply each bit by its corresponding power of 2 and add all the terms up.
0101 1111 0110 0100 0101 1101 0100 1010(2) =
(0 × 231 + 1 × 230 + 0 × 229 + 1 × 228 + 1 × 227 + 1 × 226 + 1 × 225 + 1 × 224 + 0 × 223 + 1 × 222 + 1 × 221 + 0 × 220 + 0 × 219 + 1 × 218 + 0 × 217 + 0 × 216 + 0 × 215 + 1 × 214 + 0 × 213 + 1 × 212 + 1 × 211 + 1 × 210 + 0 × 29 + 1 × 28 + 0 × 27 + 1 × 26 + 0 × 25 + 0 × 24 + 1 × 23 + 0 × 22 + 1 × 21 + 0 × 20)(10) =
(0 + 1 073 741 824 + 0 + 268 435 456 + 134 217 728 + 67 108 864 + 33 554 432 + 16 777 216 + 0 + 4 194 304 + 2 097 152 + 0 + 0 + 262 144 + 0 + 0 + 0 + 16 384 + 0 + 4 096 + 2 048 + 1 024 + 0 + 256 + 0 + 64 + 0 + 0 + 8 + 0 + 2 + 0)(10) =
(1 073 741 824 + 268 435 456 + 134 217 728 + 67 108 864 + 33 554 432 + 16 777 216 + 4 194 304 + 2 097 152 + 262 144 + 16 384 + 4 096 + 2 048 + 1 024 + 256 + 64 + 8 + 2)(10) =
1 600 413 002(10)
6. If needed, adjust the sign of the integer number by the first digit (leftmost) of the signed binary:
0101 1111 0110 0100 0101 1101 0100 1010(2) = 1 600 413 002(10)
The number 0101 1111 0110 0100 0101 1101 0100 1010(2), signed binary in two's (2's) complement representation, converted and written as an integer in decimal system (base ten):
0101 1111 0110 0100 0101 1101 0100 1010(2) = 1 600 413 002(10)
Spaces were used to group digits: for binary, by 4, for decimal, by 3.