Jupyter Notebook example OverflowError raised

[ChrisXtrac]

When using the Python wrapper jupyter notebook example the following error is raised "OverflowError: Python integer 32768 out of bounds for int16".
I've tracked it down to a possible bug in the file cmsisdsp/fixedpoint.py.
The q15sat function looks like it needs a sign added to the negative saturation logic as shown below and I also think this need to be added to the other saturation functions.

The system was as follows:

• Windows 10
• Python 3.12.6
• cmsisdsp 1.9.9
• Numpy 2.0.0

def q15sat(x):
     if x > 0x7FFF:
          return(np.int16(0x7FFF))
     elif x < -0x8000:
          return(np.int16(-0x8000))
     else:
          return(np.int16(x))

[christophe0606]

@ChrisXtrac Perhaps I'll remove those convenience functions in the future because you can use the equivalent CMSIS-DSP function. For instance:

dsp.arm_float_to_q15([0.9])

Only difference is that it is using arrays.

I agree the fixedpoint.py functions need more testing.