CODEWITHSUNDEEP
python
dorphalsig
dorphalsig

Reputation: 711

Converting Bytes to Fixed point

I'm reading some bytes from a binary file and I'm trying to convert them to decimals. They are big endian, so I try to unpack them as unpack('>f',bytes), but I'm getting the wrong result.

According to the specification I should be looking for

Fixed point numbers with 8 bits before the binary point and 24 bits after the binary point. Three guard bits are reserved in the points to eliminate most concerns over arithmetic overflow. Hence, the range for each component is 0xF0000000 to 0x0FFFFFFF representing a range of -16 to 16.

As an example I'm using 0x00d4f9c1, which should give me 0,831936, but I'm getting 1,95587[...]e-38.

Upvotes: 1

Views: 458

Answers (1)

Tim Roberts
Tim Roberts

Reputation: 54698

The f designator is for floating point, which is entirely different from fixed point. You just need to convert that to an integer and divide by 2**24.

>>> x = 0x00d4f9c1
>>> x/(1<<24)
0.8319359421730042
>>>

Upvotes: 2

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