tests/c_files/iir_4_64.c

   1 /* 4-cascaded IIR biquad filter processing 64 points */
   2 /* Modified to use arrays - SMP */
   3
   4 //#include "traps.h"
   5
   6 #define NPOINTS 64
   7 #define NSECTIONS 4
   8
   9 float input[NPOINTS];
  10 float output[NPOINTS];
  11 float coefficient[NSECTIONS][NSECTIONS][NSECTIONS];
  12 float internal_state[8][NSECTIONS][2];
  13
  14 void iir(float input[NPOINTS], float output[NPOINTS],
  15          float coefficient[NSECTIONS][NSECTIONS][NSECTIONS],
  16          float internal_state[8][NSECTIONS][2]);
  17
  18 main()
  19 {
  20   int i;
  21
  22   float *pcoef = coefficient[0][0];
  23   float *pint = internal_state[0][0];
  24
  25   for(i=0;i<NPOINTS;i++)
  26   {
  27     pcoef[i]=1;
  28     pint[i]=1;
  29   }
  30   //input_dsp(input,NPOINTS,0);
  31
  32   iir(input, output, coefficient, internal_state);
  33
  34   //output_dsp(input,NPOINTS,0);
  35   //output_dsp(coefficient,NPOINTS,0);
  36   //output_dsp(internal_state,NPOINTS,0);
  37   //output_dsp(output,NPOINTS,0);
  38 }
  39
  40 void iir(float input[NPOINTS], float output[NPOINTS],
  41          float coefficient[NSECTIONS][NSECTIONS][NSECTIONS],
  42          float internal_state[8][NSECTIONS][2])
  43 /* input:           input sample array */
  44 /* output:          output sample array */
  45 /* coefficient:     coefficient array */
  46 /* internal_state:  internal state array */
  47 {
  48   int i, imod8, imodNSECTIONS;
  49   int j;
  50
  51   float state_2, state_1;
  52   float coef_a21, coef_a11, coef_b21, coef_b11;
  53   float sum;
  54
  55   for (i = 0; i < NPOINTS; ++i) {
  56
  57     imod8 = i % 8;
  58     imodNSECTIONS = i % NSECTIONS;
  59
  60 #pragma scop
  61     sum = input[i];
  62
  63     for (j = 0; j < NSECTIONS; ++j) {
  64
  65       state_2 = internal_state[imod8][j][0];
  66       state_1 = internal_state[imod8][j][1];
  67
  68       sum -= internal_state[imod8][j][0] * coefficient[imodNSECTIONS][j][0] +
  69                 internal_state[imod8][j][1] * coefficient[imodNSECTIONS][j][1];
  70
  71       internal_state[imod8][j][0] = internal_state[imod8][j][1];
  72       internal_state[imod8][j][1] = sum;
  73
  74       sum += state_2 * coefficient[imodNSECTIONS][j][2] +
  75                                 state_1 * coefficient[imodNSECTIONS][j][3];
  76
  77     }
  78
  79     output[i] = sum;
  80 #pragma endscop
  81
  82   }
  83 }