FPGA - how to set array to zero

[Thomas444]

I use a signal filtering subVI applied on a fixed size array. Depending on cRIO configuration, I use different fixed size array.

The thing is that I need to initialize filters with zeros. As maximum effectiveness in resources usage is required, I want to know how to get the fixed size array and set it to zero with most efficient way. Ideas that come to my mind:

Multiply by zero

Bit shift right 32 times (datatype I32)

Size of fixed size array is constant -> wiring "array size" output to initialize array (not working, size of fixed size array is not considered constant)

[Thomas444]

Or maybe subtract array from itself

[cordm]

Another idea: xor the array with itself.

I doubt there will be a significant performance difference between initialization methods. If the compiler recognizes the pattern, it should optimize it to a constant.

[GerdW]

Hi,

use a memory item in the FPGA: here you can define intial values…

[Intaris]

Do you need this during run-time or only at startup?

[tvirag]

I did some testing and both multiplication by zero and subtracting the array from itself works in a single-cycle timed loop. This means you can do the initialization in the timeframe of one click.

[Intaris]

Or just create a constant and use a select primitive.