Fixed point binary and back python

Question

I am fairly new to python is there a fast way to convert decimal to 16-bit fixed-point binary (1-bit sign – 7-bit integer – 8-bit fraction) and back in python.

I would like to manipulate the binary and convert this manipulated binary back to decimal.

Example 1.25 -> 00000001.01000000

Manipulate first fraction part (0->1)

00000001.11000000 -> 1.75

Would really appreciate any help.

Answer 1

If you have N bits in the fractional part then you just need to divide by 2^N, since the stored bit pattern is actually the real value multiplied by 2^N. Therefore with Q8.8 like in your case you'll have to divide by 256

For your 00000001.01000000 and 00000001.11000000 examples above:

>>> 0b0000000101000000/256.0
1.25
>>> 0b0000000111000000/256.0
1.75