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?
0011 1010 1100 1001 0111 1100 0100 0001 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
0 229
1 228
1 227
1 226
0 225
1 224
0 223
1 222
1 221
0 220
0 219
1 218
0 217
0 216
1 215
0 214
1 213
1 212
1 211
1 210
1 29
0 28
0 27
0 26
1 25
0 24
0 23
0 22
0 21
0 20
1
5. Multiply each bit by its corresponding power of 2 and add all the terms up.
0011 1010 1100 1001 0111 1100 0100 0001(2) =
(0 × 231 + 0 × 230 + 1 × 229 + 1 × 228 + 1 × 227 + 0 × 226 + 1 × 225 + 0 × 224 + 1 × 223 + 1 × 222 + 0 × 221 + 0 × 220 + 1 × 219 + 0 × 218 + 0 × 217 + 1 × 216 + 0 × 215 + 1 × 214 + 1 × 213 + 1 × 212 + 1 × 211 + 1 × 210 + 0 × 29 + 0 × 28 + 0 × 27 + 1 × 26 + 0 × 25 + 0 × 24 + 0 × 23 + 0 × 22 + 0 × 21 + 1 × 20)(10) =
(0 + 0 + 536 870 912 + 268 435 456 + 134 217 728 + 0 + 33 554 432 + 0 + 8 388 608 + 4 194 304 + 0 + 0 + 524 288 + 0 + 0 + 65 536 + 0 + 16 384 + 8 192 + 4 096 + 2 048 + 1 024 + 0 + 0 + 0 + 64 + 0 + 0 + 0 + 0 + 0 + 1)(10) =
(536 870 912 + 268 435 456 + 134 217 728 + 33 554 432 + 8 388 608 + 4 194 304 + 524 288 + 65 536 + 16 384 + 8 192 + 4 096 + 2 048 + 1 024 + 64 + 1)(10) =
986 283 073(10)
6. If needed, adjust the sign of the integer number by the first digit (leftmost) of the signed binary:
0011 1010 1100 1001 0111 1100 0100 0001(2) = 986 283 073(10)
The number 0011 1010 1100 1001 0111 1100 0100 0001(2), signed binary in two's (2's) complement representation, converted and written as an integer in decimal system (base ten):
0011 1010 1100 1001 0111 1100 0100 0001(2) = 986 283 073(10)
Spaces were used to group digits: for binary, by 4, for decimal, by 3.