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   $Id$
   Author(s):   M. Lohwasser
   Description: auto-correlation functions

   This software and/or program is protected by copyright law and international
   treaties. Any reproduction or distribution of this software and/or program,
   or any portion of it, may result in severe civil and criminal penalties, and
   will be prosecuted to the maximum extent possible under law.

******************************************************************************/

#include "autocorr2nd.h"



/*  If the accumulator does not provide enough overflow bits,
    products have to be shifted down in the autocorrelation below. */
#define SHIFT_FACTOR (5)
#define SHIFT >> (SHIFT_FACTOR)


#if defined(__CC_ARM) || defined(__arm__)
#include "arm/autocorr2nd.cpp"
#endif


/*!
 *
 * \brief Calculate second order autocorrelation using 2 accumulators
 *
 */
#if !defined(FUNCTION_autoCorr2nd_real)
INT
autoCorr2nd_real (ACORR_COEFS *ac,          /*!< Pointer to autocorrelation coeffs */
                  const FIXP_DBL *reBuffer, /*!< Pointer to to real part of input samples */
                  const int len             /*!< Number input samples */
                 )
{
  int   j, autoCorrScaling, mScale;

  FIXP_DBL accu1, accu2, accu3, accu4, accu5;

  const FIXP_DBL *pReBuf;

  const FIXP_DBL *realBuf = reBuffer;

  /*
    r11r,r22r
    r01r,r12r
    r02r
  */
  pReBuf = realBuf-2;
  accu5 = ( (fMultDiv2(pReBuf[0], pReBuf[2]) +
             fMultDiv2(pReBuf[1], pReBuf[3])) SHIFT);
  pReBuf++;

  //len must be even
  accu1 = fPow2Div2(pReBuf[0]) SHIFT;
  accu3 = fMultDiv2(pReBuf[0], pReBuf[1]) SHIFT;
  pReBuf++;

  for ( j = (len - 2)>>1; j != 0; j--,pReBuf+=2 ) {

    accu1 += ( (fPow2Div2(pReBuf[0]) +
                fPow2Div2(pReBuf[1])) SHIFT);

    accu3 += ( (fMultDiv2(pReBuf[0], pReBuf[1]) +
                fMultDiv2(pReBuf[1], pReBuf[2])) SHIFT);

    accu5 += ( (fMultDiv2(pReBuf[0], pReBuf[2]) +
                fMultDiv2(pReBuf[1], pReBuf[3])) SHIFT);

  }

  accu2 = (fPow2Div2(realBuf[-2]) SHIFT);
  accu2 += accu1;

  accu1 += (fPow2Div2(realBuf[len - 2]) SHIFT);

  accu4  = (fMultDiv2(realBuf[-1],realBuf[-2]) SHIFT);
  accu4 += accu3;

  accu3 += (fMultDiv2(realBuf[len - 1],realBuf[len - 2]) SHIFT);

  mScale = CntLeadingZeros( (accu1 | accu2 | fAbs(accu3) | fAbs(accu4) | fAbs(accu5)) ) - 1;
  autoCorrScaling = mScale - 1 - SHIFT_FACTOR; /* -1 because of fMultDiv2*/

  /* Scale to common scale factor */
  ac->r11r = accu1 << mScale;
  ac->r22r = accu2 << mScale;
  ac->r01r = accu3 << mScale;
  ac->r12r = accu4 << mScale;
  ac->r02r = accu5 << mScale;

  ac->det = (fMultDiv2(ac->r11r,ac->r22r) - fMultDiv2(ac->r12r,ac->r12r)) ;
  mScale  = CountLeadingBits(fAbs(ac->det));

  ac->det     <<= mScale;
  ac->det_scale = mScale - 1;

  return autoCorrScaling;
}
#endif

#ifndef LOW_POWER_SBR_ONLY
#if !defined(FUNCTION_autoCorr2nd_cplx)
INT
autoCorr2nd_cplx (ACORR_COEFS *ac,           /*!< Pointer to autocorrelation coeffs */
                  const FIXP_DBL *reBuffer,  /*!< Pointer to real part of input samples */
                  const FIXP_DBL *imBuffer,  /*!< Pointer to imag part of input samples */
                  const int len              /*!< Number of input samples */
                 )
{

  int   j, autoCorrScaling, mScale, len_scale;

  FIXP_DBL accu0, accu1,accu2, accu3, accu4, accu5, accu6, accu7, accu8;

  const FIXP_DBL *pReBuf, *pImBuf;

  const FIXP_DBL *realBuf = reBuffer;
  const FIXP_DBL *imagBuf = imBuffer;

  (len>64) ? (len_scale = 6) : (len_scale = 5);
  /*
    r00r,
    r11r,r22r
    r01r,r12r
    r01i,r12i
    r02r,r02i
  */
  accu1 = accu3 = accu5 = accu7 = accu8 = FL2FXCONST_DBL(0.0f);

  pReBuf  = realBuf-2, pImBuf  = imagBuf-2;
  accu7 += ( (fMultDiv2(pReBuf[2], pReBuf[0]) + fMultDiv2(pImBuf[2], pImBuf[0])) >> len_scale);
  accu8 += ( (fMultDiv2(pImBuf[2], pReBuf[0]) - fMultDiv2(pReBuf[2], pImBuf[0])) >> len_scale);

  pReBuf = realBuf-1, pImBuf = imagBuf-1;
  for ( j = (len - 1); j != 0; j--,pReBuf++,pImBuf++ ){
    accu1 += ( (fPow2Div2(pReBuf[0]           ) + fPow2Div2(pImBuf[0]           )) >> len_scale);
    accu3 += ( (fMultDiv2(pReBuf[0], pReBuf[1]) + fMultDiv2(pImBuf[0], pImBuf[1])) >> len_scale);
    accu5 += ( (fMultDiv2(pImBuf[1], pReBuf[0]) - fMultDiv2(pReBuf[1], pImBuf[0])) >> len_scale);
    accu7 += ( (fMultDiv2(pReBuf[2], pReBuf[0]) + fMultDiv2(pImBuf[2], pImBuf[0])) >> len_scale);
    accu8 += ( (fMultDiv2(pImBuf[2], pReBuf[0]) - fMultDiv2(pReBuf[2], pImBuf[0])) >> len_scale);
  }

  accu2 = ( (fPow2Div2(realBuf[-2]) + fPow2Div2(imagBuf[-2])) >> len_scale);
  accu2 += accu1;

  accu1 += ( (fPow2Div2(realBuf[len-2]) +
              fPow2Div2(imagBuf[len-2])) >> len_scale);
  accu0 = ( (fPow2Div2(realBuf[len-1]) +
             fPow2Div2(imagBuf[len-1])) >> len_scale) -
          ( (fPow2Div2(realBuf[-1]) +
             fPow2Div2(imagBuf[-1])) >> len_scale);
  accu0 += accu1;

  accu4 = ( (fMultDiv2(realBuf[-1], realBuf[-2]) +
             fMultDiv2(imagBuf[-1], imagBuf[-2])) >> len_scale);
  accu4 += accu3;

  accu3 += ( (fMultDiv2(realBuf[len-1], realBuf[len-2]) +
              fMultDiv2(imagBuf[len-1], imagBuf[len-2])) >> len_scale);

  accu6 = ( (fMultDiv2(imagBuf[-1], realBuf[-2]) -
             fMultDiv2(realBuf[-1], imagBuf[-2])) >> len_scale);
  accu6 += accu5;

  accu5 += ( (fMultDiv2(imagBuf[len - 1], realBuf[len - 2]) -
              fMultDiv2(realBuf[len - 1], imagBuf[len - 2])) >> len_scale);

  mScale = CntLeadingZeros( (accu0 | accu1 | accu2 | fAbs(accu3) | fAbs(accu4) | fAbs(accu5) |
                             fAbs(accu6) | fAbs(accu7) | fAbs(accu8)) ) - 1;
  autoCorrScaling = mScale - 1 - len_scale; /* -1 because of fMultDiv2*/

  /* Scale to common scale factor */
  ac->r00r = (FIXP_DBL)accu0 << mScale;
  ac->r11r = (FIXP_DBL)accu1 << mScale;
  ac->r22r = (FIXP_DBL)accu2 << mScale;
  ac->r01r = (FIXP_DBL)accu3 << mScale;
  ac->r12r = (FIXP_DBL)accu4 << mScale;
  ac->r01i = (FIXP_DBL)accu5 << mScale;
  ac->r12i = (FIXP_DBL)accu6 << mScale;
  ac->r02r = (FIXP_DBL)accu7 << mScale;
  ac->r02i = (FIXP_DBL)accu8 << mScale;

  ac->det = ( fMultDiv2(ac->r11r,ac->r22r) >> 1 ) -
            ( (fMultDiv2(ac->r12r,ac->r12r) + fMultDiv2(ac->r12i,ac->r12i)) >> 1 );
  mScale = CountLeadingBits(fAbs(ac->det));

  ac->det <<= mScale;
  ac->det_scale = mScale - 2;

  return autoCorrScaling;
}
#endif /* FUNCTION_autoCorr2nd_cplx */
#endif /* LOW_POWER_SBR_ONLY */