Conversion from HEX to SIGNED DEC in python
python
Solution
You can interpret the bytes as a two's complement signed integer using bitwise operations. For example, for a 16-bit number:
def s16(value):
return -(value & 0x8000) | (value & 0x7fff)
Therefore:
>>> s16(int('0xffd2', 16))
-46
>>> s16(int('0xffcb', 16))
-53
>>> s16(int('0xffcc', 16))
-52
>>> s16(int('0x10', 16))
16
>>> s16(int('0xd', 16))
13
>>> s16(int('0x0', 16))
0
>>> s16(int('0xfffe', 16))
-2
This can be extended to any bit-length string, by setting the masks so the first mask matches the most-significant bit (`0x8000 == 1 << 15 == 0b1000000000000000`) and the second mask matches the all the remaining bits (`0x7fff == (1 << 15) - 1 == 0b0111111111111111`).
Problem
I have a file with HEX data I want to convert it into SIGNED DECIMAL using python. `int('0xffd2',16)` is not the solution since it converts the HEX to unsigned DEC. Any idea how to do it? ``` 0xffd2, 65490 0xffcb, 65483 0xffcb, 65483 0xffcc, 65484 0x10, 16 0xc, 12 0xd, 13 0x0, 0 0xfffe, 65534 ```