apps/codecs/libwmapro/wmapro_mdct.c

   1 #include <inttypes.h>
   2 #include "wmapro_mdct.h"
   3 #include "mdct_tables.h"    /* for sincos_lookup_wmap */
   4 #include "../lib/mdct_lookup.h" /* for revtab */
   5 #include "../lib/fft.h"     /* for FFT data structures */
   6 #include "codeclib.h"
   7
   8  /* for XNPROD31 */
   9 #include "asm_arm.h"
  10 #include "asm_mcf5249.h"
  11 #include "codeclib_misc.h"
  12
  13 #include "wmapro_math.h"
  14
  15 void imdct_half(unsigned int nbits, int32_t *output, const int32_t *input){
  16     int k, n8, n4, n2, n, j;
  17     const int32_t *in1, *in2;
  18     FFTComplex *z = (FFTComplex *)output;
  19
  20     n = 1 << nbits;
  21     n2 = n >> 1;
  22     n4 = n >> 2;
  23     n8 = n >> 3;
  24
  25     const int32_t *T = sincos_lookup_wmap + ((n2) - (1<<7));
  26
  27     /* pre rotation */
  28     const int revtab_shift = (14- nbits);
  29     in1 = input;
  30     in2 = input + n2 - 1;
  31     for(k = 0; k < n4; k++) {
  32         j=revtab[k]>>revtab_shift;
  33         XNPROD31(*in2<<2, *in1<<2, T[1]<<14, T[0]<<14, &z[j].re, &z[j].im );
  34         in1 += 2;
  35         in2 -= 2;
  36         T += 2;
  37     }
  38
  39     ff_fft_calc_c(nbits-2, z);
  40
  41     /* post rotation + reordering */
  42     T = sincos_lookup_wmap + ((n2) - (1<<7)) + n4;
  43     const int32_t *V = T;
  44     for(k = 0; k < n8; k++) {
  45         int32_t r0, i0, r1, i1;
  46         XNPROD31(z[n8-k-1].im, z[n8-k-1].re, T[0]<<8, T[1]<<8, &r0, &i1 );
  47         XNPROD31(z[n8+k  ].im, z[n8+k  ].re, V[0]<<8, V[1]<<8, &r1, &i0 );
  48         z[n8-k-1].re = r0;
  49         z[n8-k-1].im = i0;
  50         z[n8+k  ].re = r1;
  51         z[n8+k  ].im = i1;
  52         T-=2;
  53         V+=2;
  54     }
  55 }