22.214.171.124. Horizontal and Vertical Symmetry
The FIR Filter IP has 2 axes of symmetry across a horizontal line and a vertical line through the center tap in the 2D coefficient array.
In this case, the number of horizontal taps (N) and the number of vertical taps (M) must be even. Horizontal and vertical symmetry offers only ((N+1)/2)×((M+1)/2) unique coefficient values. The remaining values in the array are mirrored duplicates.
With run-time control of the coefficients, the register map only includes addresses to update the ((N+1)/2)×((M+1)/2) unique coefficient values, indexed for an example 5×5 array.