22.214.171.124. Horizontal Symmetry
The FIR Filter IP has 1 axis of symmetry across a vertical line through the center tap in the 2D coefficient array.
The number of vertical taps (M) may be even or odd, but the number of horizontal taps (N) must be odd. Horizontal symmetry offers only ((N+1)/2)×M 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 unique coefficient values, indexed for an example 5×5 array as shown in the figure below.