What is "4 different data type filter instance structures" in Finite Impulse Response (FIR) Filters?

Hi,

On NE10 library, I do not understand what is "4 different data type filter instance structures " in the following paragraph. Similarly, I do not understand "4 supported data types" either.

Could you explain them to me?

Thanks,

............................

Instance Structure

The coefficients and state variables for a filter are stored together in an instance data structure. A separate instance structure must be defined for each filter. Coefficient arrays may be shared among several instances while state variable arrays cannot be shared. There are separate instance structure declarations for each of the 4 supported data types.

Initialization Functions

There is also an associated initialization function for each data type. The initialization function performs the following operations:

• Sets the values of the internal structure fields.
• Zeros out the values in the state buffer.

Use of the initialization function is optional. However, if the initialization function is used, then the instance structure cannot be placed into a const data section. To place an instance structure into a const data section, the instance structure must be manually initialized. Set the values in the state buffer to zeros before static initialization. The code below statically initializes each of the 4 different data type filter instance structures

ne10_fir_instance_f32_t S = {numTaps, pState, pCoeffs};