template class xf::dsp::aie::fir::sr_sym::fir_sr_sym_graph

#include "fir_sr_sym_graph.hpp"


fir_sr_sym is a Symmetrical Single Rate FIR filter

These are the templates to configure the Symmetric Single Rate FIR class.


TT_DATA describes the type of individual data samples input to and output from the filter function. This is a typename and must be one of the following: int16, cint16, int32, cint32, float, cfloat.

describes the type of individual coefficients of the filter taps. It must be one of the same set of types listed for TT_DATA and must also satisfy the following rules:

  • Complex types are only supported when TT_DATA is also complex.
  • 32 bit types are only supported when TT_DATA is also a 32 bit type,
  • TT_COEFF must be an integer type if TT_DATA is an integer type
  • TT_COEFF must be a float type if TT_DATA is a float type.
TP_FIR_LEN is an unsigned integer which describes the number of taps in the filter.
TP_SHIFT is describes power of 2 shift down applied to the accumulation of FIR terms before output. TP_SHIFT must be in the range 0 to 61.

describes the selection of rounding to be applied during the shift down stage of processing. TP_RND must be in the range 0 to 7 where

  • 0 = floor (truncate) eg. 3.8 Would become 3.
  • 1 = ceiling e.g. 3.2 would become 4.
  • 2 = round to positive infinity.
  • 3 = round to negative infinity.
  • 4 = round symmetrical to infinity.
  • 5 = round symmetrical to zero.
  • 6 = round convergent to even.
  • 7 = round convergent to odd. Modes 2 to 7 round to the nearest integer. They differ only in how they round for values of 0.5.
TP_CASC_LEN describes the number of AIE processors to split the operation over. This allows resource to be traded for higher performance. TP_CASC_LEN must be in the range 1 (default) to 9.
TP_INPUT_WINDOW_VSIZE describes the number of samples in the window API used for input to the filter function. The number of values in the output window will be TP_INPUT_WINDOW_VSIZE by virtue the single rate nature of this filter. Note: Margin size should not be included in TP_INPUT_WINDOW_VSIZE.
TP_NUM_OUTPUTS sets the number of ports to broadcast the output to. This is the class for the Symmetric Single Rate FIR graph
template <
    typename TT_DATA,
    typename TT_COEFF,
    unsigned int TP_FIR_LEN,
    unsigned int TP_SHIFT,
    unsigned int TP_RND,
    unsigned int TP_INPUT_WINDOW_VSIZE,
    unsigned int TP_CASC_LEN = 1,
    unsigned int TP_USE_COEFF_RELOAD = 0,
    unsigned int TP_NUM_OUTPUTS = 1
class fir_sr_sym_graph: public graph

// fields

port <input> in
port <output> out


port <input> in

The input data to the function. This input is a window API of samples of TT_DATA type. The number of samples in the window is described by TP_INPUT_WINDOW_VSIZE. Note: Margin is added internally to the graph, when connecting input port with kernel port. Therefore, margin should not be added when connecting graph to a higher level design unit. Margin size (in Bytes) equals to TP_FIR_LEN rounded up to a nearest multiple of 32 bytes.

port <output> out

A window API of TP_INPUT_WINDOW_VSIZE samples of TT_DATA type.



kernel* getKernels ()

Access function to get pointer to kernel (or first kernel in a chained configuration).


fir_sr_sym_graph (const std::vector <TT_COEFF>& taps)

This is the constructor function for the Symmetric Singlr Rate FIR graph.


  • a pointer to the array of taps values of type TT_COEFF. The taps array need only be supplied for the first half of the filter length plus the center tap for odd lengths i.e. taps[] = {c0, c1, c2, …, cN [, cCT]} where N = TP_FIR_LEN/2 and cCT is the center tap where TP_FIR_LEN is odd. For example, a 7-tap filter might use coeffs (1, 3, 2, 5, 2, 3, 1). This could be input as taps[]= {1,3,2,5} since the context of symmetry allows the remaining coefficients to be inferred.