sp_frm.c

GSM半数率源代码(VSELP) GSM半数率源代码(VSELP)

    }
    else
    {
      if (j == psvqIndex[iSegment - 1].len - 2)
      {

        /* Then recursion to be done for one more lattice stage */
        /*------------------------------------------------------*/

        /* Copy address of PNew into POld */
        /*--------------------------------*/
        pL_POld = ppL_PAddrs[(j + 1) % 2];

        /* Copy address of the input pL_PBar array into pswPNew; this will */
        /* cause the PNew array to overwrite the input pL_PBar array, thus */
        /* updating it at the final lattice stage of the current segment   */
        /*-----------------------------------------------------------------*/

        pL_PNew = pL_PBar;

        /* Copy address of VNew into VOld */
        /*--------------------------------*/

        pL_VOld = ppL_VAddrs[(j + 1) % 2];

        /* Copy address of the input pL_VBar array into pswVNew; this will */
        /* cause the VNew array to overwrite the input pL_VBar array, thus */
        /* updating it at the final lattice stage of the current segment   */
        /*-----------------------------------------------------------------*/

        pL_VNew = pL_VBar;

      }
    }
  }

  /* Update the pswPBar and pswVBar initial conditions for the AFLAT      */
  /* Rc-VQ search at the next segment.                                    */
  /*----------------------------------------------------------------------*/

  bound = psvqIndex[iSegment].len - 1;

  for (i = 0; i <= bound; i++)
  {
    pswPBar[i] = round(pL_PBar[i]);
    pswVBar[i] = round(pL_VBar[i]);
  }
  for (i = -bound; i < 0; i++)
  {
    pswVBar[i] = round(pL_VBar[i]);
  }

  return;
}

/***************************************************************************
 *
 *    FUNCTION NAME: aflatRecursion
 *
 *    PURPOSE:  Given the Shortword initial condition arrays, pswPBar and
 *              pswVBar, a reflection coefficient vector from the quantizer
 *              (or a prequantizer), and the order of the current Rc-VQ
 *              segment, function aflatRecursion computes and returns the
 *              residual error energy by evaluating the AFLAT recursion.
 *
 *              This is an implementation of equations 4.18 to 4.23.
 *    INPUTS:
 *
 *        pswQntRc[0:NP_AFLAT-1]
 *                     An input reflection coefficient vector from the
 *                     Rc-prequantizer or the Rc-VQ codebook.
 *
 *        pswPBar[0:NP_AFLAT-1]
 *                     The input Shortword array containing the P initial
 *                     conditions for the P-V AFLAT recursion at the current
 *                     Rc-VQ segment. The address of the 0-th element of
 *                     pswVBar is passed in.
 *
 *        pswVBar[-NP_AFLAT+1:NP_AFLAT-1]
 *                     The input Shortword array containing the V initial
 *                     conditions for the P-V AFLAT recursion, at the current
 *                     Rc-VQ segment. The address of the 0-th element of
 *                     pswVBar is passed in.
 *
 *        *ppswPAddrs[0:1]
 *                     An input array containing the address of temporary
 *                     space P1 in its 0-th element, and the address of
 *                     temporary space P2 in its 1-st element. Each of
 *                     these addresses is alternately assigned onto
 *                     pswPNew and pswPOld pointers using modulo
 *                     arithmetic, so as to avoid copying the contents of
 *                     pswPNew array into the pswPOld array at the end of
 *                     each lattice stage of the AFLAT recursion.
 *                     Temporary space P1 and P2 is allocated outside
 *                     aflatRecursion by the calling function aflat.
 *
 *        *ppswVAddrs[0:1]
 *                     An input array containing the address of temporary
 *                     space V1 in its 0-th element, and the address of
 *                     temporary space V2 in its 1-st element. Each of
 *                     these addresses is alternately assigned onto
 *                     pswVNew and pswVOld pointers using modulo
 *                     arithmetic, so as to avoid copying the contents of
 *                     pswVNew array into the pswVOld array at the end of
 *                     each lattice stage of the AFLAT recursion.
 *                     Temporary space V1 and V2 is allocated outside
 *                     aflatRecursion by the calling function aflat.
 *
 *        swSegmentOrder
 *                     This input short word describes the number of
 *                     stages needed to compute the vector
 *                     quantization of the given segment.
 *
 *    OUTPUTS:
 *        None.
 *
 *    RETURN:
 *        swRe         The Shortword value of residual energy for the
 *                     Rc vector, given the pswPBar and pswVBar initial
 *                     conditions.
 *
 *    REFERENCE:  Sub-clause 4.1.4.1 GSM Recommendation 06.20
 *
 *************************************************************************/

Shortword aflatRecursion(Shortword pswQntRc[],
                                Shortword pswPBar[],
                                Shortword pswVBar[],
                                Shortword *ppswPAddrs[],
                                Shortword *ppswVAddrs[],
                                Shortword swSegmentOrder)
{

/*_________________________________________________________________________
 |                                                                         |
 |                            Automatic Variables                          |
 |_________________________________________________________________________|
*/

  Shortword *pswPOld,
        *pswPNew,
        *pswVOld,
        *pswVNew,
         pswQntRcSqd[NP_AFLAT],
         swRe;
  Longword L_sum;
  short int i,
         j,
         bound;                        /* loop control variables */

/*_________________________________________________________________________
 |                                                                         |
 |                              Executable Code                            |
 |_________________________________________________________________________|
*/

  /* Point to PBar and VBar, the initial condition arrays for the AFLAT  */
  /* recursion.                                                          */
  /*---------------------------------------------------------------------*/

  pswPOld = pswPBar;
  pswVOld = pswVBar;

  /* Point to PNew and VNew, the arrays into which updated values of  P  */
  /* and V functions will be written.                                    */
  /*---------------------------------------------------------------------*/

  pswPNew = ppswPAddrs[1];
  pswVNew = ppswVAddrs[1];

  /* Compute the residual error energy due to the selected Rc vector */
  /* using the AFLAT recursion.                                      */
  /*-----------------------------------------------------------------*/

  /* Compute rc squared, used by the recursion */
  /*-------------------------------------------*/

  for (j = 0; j < swSegmentOrder; j++)
  {
    pswQntRcSqd[j] = mult_r(pswQntRc[j], pswQntRc[j]);
  }

  /* Compute the residual error energy due to the selected Rc vector */
  /* using the AFLAT recursion.                                      */
  /*-----------------------------------------------------------------*/

  for (j = 0; j < swSegmentOrder - 1; j++)
  {
    bound = swSegmentOrder - j - 2;

    /* Compute Psubj(i), for i = 0, bound  */
    /*-------------------------------------*/

    for (i = 0; i <= bound; i++)
    {
      L_sum = L_mac(L_ROUND, pswVOld[i], pswQntRc[j]);
      L_sum = L_mac(L_sum, pswVOld[-i], pswQntRc[j]);
      L_sum = L_mac(L_sum, pswPOld[i], pswQntRcSqd[j]);
      L_sum = L_msu(L_sum, pswPOld[i], SW_MIN);
      pswPNew[i] = extract_h(L_sum);
    }

    /* Check if potential for limiting exists. */
    /*-----------------------------------------*/

    if (sub(pswPNew[0], 0x4000) >= 0)
      iLimit = 1;

    /* Compute the new Vsubj(i) */
    /*--------------------------*/

    for (i = -bound; i < 0; i++)
    {
      L_sum = L_msu(L_ROUND, pswVOld[i + 1], SW_MIN);
      L_sum = L_mac(L_sum, pswQntRcSqd[j], pswVOld[-i - 1]);
      L_sum = L_mac(L_sum, pswQntRc[j], pswPOld[-i - 1]);
      L_sum = L_mac(L_sum, pswQntRc[j], pswPOld[-i - 1]);
      pswVNew[i] = extract_h(L_sum);
    }

    for (i = 0; i <= bound; i++)
    {
      L_sum = L_msu(L_ROUND, pswVOld[i + 1], SW_MIN);
      L_sum = L_mac(L_sum, pswQntRcSqd[j], pswVOld[-i - 1]);
      L_sum = L_mac(L_sum, pswQntRc[j], pswPOld[i + 1]);
      L_sum = L_mac(L_sum, pswQntRc[j], pswPOld[i + 1]);
      pswVNew[i] = extract_h(L_sum);
    }

    if (j < swSegmentOrder - 2)
    {

      /* Swap POld and PNew buffers, using modulo addressing */
      /*-----------------------------------------------------*/

      pswPOld = ppswPAddrs[(j + 1) % 2];
      pswPNew = ppswPAddrs[j % 2];

      /* Swap VOld and VNew buffers, using modulo addressing */
      /*-----------------------------------------------------*/

      pswVOld = ppswVAddrs[(j + 1) % 2];
      pswVNew = ppswVAddrs[j % 2];

    }
  }

  /* Computing Psubj(0) for the last lattice stage */
  /*-----------------------------------------------*/

  j = swSegmentOrder - 1;

  L_sum = L_mac(L_ROUND, pswVNew[0], pswQntRc[j]);
  L_sum = L_mac(L_sum, pswVNew[0], pswQntRc[j]);
  L_sum = L_mac(L_sum, pswPNew[0], pswQntRcSqd[j]);
  L_sum = L_msu(L_sum, pswPNew[0], SW_MIN);
  swRe = extract_h(L_sum);

  /* Return the residual energy corresponding to the reflection   */
  /* coefficient vector being evaluated.                          */
  /*--------------------------------------------------------------*/

  return (swRe);                       /* residual error is returned */

}

/***************************************************************************
 *
 *   FUNCTION NAME: bestDelta
 *
 *   PURPOSE:
 *
 *     This function finds the delta-codeable lag which maximizes CC/G.
 *
 *   INPUTS:
 *
 *     pswLagList[0:siNumLags-1]
 *
 *                     List of delta-codeable lags over which search is done.
 *
 *     pswCSfrm[0:127]
 *
 *                     C(k) sequence, k integer.
 *
 *     pswGSfrm[0:127]
 *
 *                     G(k) sequence, k integer.
 *
 *     siNumLags
 *
 *                     Number of lags in contention.
 *
 *     siSfrmIndex
 *
 *                     The index of the subframe to which the delta-code
 *                     applies.
 *
 *
 *   OUTPUTS:
 *
 *     pswLTraj[0:3]
 *
 *                     The winning lag is put into this array at
 *                     pswLTraj[siSfrmIndex]
 *
 *     pswCCTraj[0:3]
 *
 *                     The corresponding winning C**2 is put into this
 *                     array at pswCCTraj[siSfrmIndex]
 *
 *     pswGTraj[0:3]
 *
 *                     The corresponding winning G is put into this arrray
 *                     at pswGTraj[siSfrmIndex]
 *
 *   RETURN VALUE:
 *
 *     none
 *
 *   DESCRIPTION:
 *
 *   REFERENCE:  Sub-clause 4.1.8.3 of GSM Recommendation 06.20
 *
 *   KEYWORDS:
 *
 *************************************************************************/

void   bestDelta(Shortword pswLagList[],
                        Shortword pswCSfrm[],
                        Shortword pswGSfrm[],
                        short int siNumLags,
                        short int siSfrmIndex,
                        Shortword pswLTraj[],
                        Shortword pswCCTraj[],
                        Shortword pswGTraj[])
{

/*_________________________________________________________________________
 |                                                                         |
 |                            Automatic Variables                          |
 |_________________________________________________________________________|
*/

  Shortword pswCBuf[DELTA_LEVELS + CG_INT_MACS + 2],
         pswGBuf[DELTA_LEVELS + CG_INT_MACS + 2],
         pswCInterp[DELTA_LEVELS + 2],
         pswGInterp[DELTA_LEVELS + 2],
        *psw1,
        *psw2,
         swCmaxSqr,
         swGmax,
         swPeak;
  short int siIPLo,
         siRemLo,
         siIPHi,
         siRemHi,
         siLoLag,
         siHiLag,
         siI;

/*_________________________________________________________________________
 |                                                                         |
 |                              Executable Code                            |
 |_________________________________________________________________________|
*/

  /* get bounds for integer C's and G's needed for interpolation */
  /* get integer and fractional portions of boundary lags        */
  /* ----------------------------------------------------------- */