c2_9pf.cpp

实现3GPP的GSM中AMR语音的CODECS。

                    rr = rr
                    codvec = codvec )
           MODIFYING(nothing)
           RETURNING(nothing)
        ----------------------------------------------------------------------------*/
        search_2i40(
            subNr,
            dn,
            rr,
            codvec,
            pOverflow);

        return;
    }

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

    /*
    ------------------------------------------------------------------------------
     FUNCTION NAME: build_code
    ------------------------------------------------------------------------------
     INPUT AND OUTPUT DEFINITIONS

     Inputs:
        subNr = subframe number (Word16)
        codvec = vector containing the position of pulses (Word16)
        dn_sign = vector containing the sign of pulses (Word16)
        cod = innovative code vector (Word16)
        h = vector containing the impulse response of the weighted
            synthesis filter (Word16)
        y = vector containing the filtered innovative code (Word16)
        sign = vector containing the sign of 2 pulses (Word16)

     Outputs:
        cod vector contains the new innovative code
        y vector contains the new filtered innovative code
        sign vector contains the sign of 2 pulses

     Returns:
        indx = codebook index (Word16)

     Global Variables Used:
        None

     Local Variables Needed:
        trackTable = table used for tracking codewords (Word16)

    ------------------------------------------------------------------------------
     FUNCTION DESCRIPTION

     This function builds the codeword, the filtered codeword and index of the
     codevector, based on the signs and positions of 2 pulses.

    ------------------------------------------------------------------------------
     REQUIREMENTS

     None

    ------------------------------------------------------------------------------
     REFERENCES

     [1] c2_9pf.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001

    ------------------------------------------------------------------------------
     PSEUDO-CODE

    static Word16 build_code(
        Word16 subNr,     // i : subframe number
        Word16 codvec[],  // i : position of pulses
        Word16 dn_sign[], // i : sign of pulses
        Word16 cod[],     // o : innovative code vector
        Word16 h[],       // i : impulse response of weighted synthesis filter
        Word16 y[],       // o : filtered innovative code
        Word16 sign[]     // o : sign of 2 pulses
    )
    {
        Word16 i, j, k, track, first, index, _sign[NB_PULSE], indx, rsign;
        Word16 *p0, *p1, *pt;
        Word32 s;
        static Word16 trackTable[4*5] = {
           0, 1, 0, 1, -1, // subframe 1; track to code; -1 do not code this position
           0, -1, 1, 0, 1, // subframe 2
           0, 1, 0, -1, 1, // subframe 3
           0, 1, -1, 0, 1};// subframe 4

        pt = &trackTable[add(subNr, shl(subNr, 2))];

        for (i = 0; i < L_CODE; i++) {
            cod[i] = 0;
        }

        indx = 0;
        rsign = 0;
        for (k = 0; k < NB_PULSE; k++) {
           i = codvec[k];    // read pulse position
           j = dn_sign[i];   // read sign

           index = mult(i, 6554);    // index = pos/5
                                     // track = pos%5
           track = sub(i, extract_l(L_shr(L_mult(index, 5), 1)));

           first = pt[track];

           if (first == 0) {
              if (k == 0) {
                 track = 0;
              } else {
                 track = 1;
                 index = shl(index, 3);
              }
           } else {
              if (k == 0) {
                 track = 0;
                 index = add(index, 64);  // table bit is MSB
              } else {
                 track = 1;
                 index = shl(index, 3);
              }
           }

           if (j > 0) {
              cod[i] = 8191;
              _sign[k] = 32767;
              rsign = add(rsign, shl(1, track));
           } else {
              cod[i] = -8192;
              _sign[k] = (Word16) - 32768L;
            }

           indx = add(indx, index);
        }
        *sign = rsign;

        p0 = h - codvec[0];
        p1 = h - codvec[1];

        for (i = 0; i < L_CODE; i++) {
           s = 0;
           s = L_mac(s, *p0++, _sign[0]);
           s = L_mac(s, *p1++, _sign[1]);
           y[i] = pv_round(s);
        }

        return indx;
    }

    ------------------------------------------------------------------------------
     RESOURCES USED [optional]

     When the code is written for a specific target processor the
     the resources used should be documented below.

     HEAP MEMORY USED: x bytes

     STACK MEMORY USED: x bytes

     CLOCK CYCLES: (cycle count equation for this function) + (variable
                    used to represent cycle count for each subroutine
                    called)
         where: (cycle count variable) = cycle count for [subroutine
                                         name]

    ------------------------------------------------------------------------------
     CAUTION [optional]
     [State any special notes, constraints or cautions for users of this function]

    ------------------------------------------------------------------------------
    */

    static Word16 build_code(
        Word16 subNr,     /* i : subframe number                            */
        Word16 codvec[],  /* i : position of pulses                         */
        Word16 dn_sign[], /* i : sign of pulses                             */
        Word16 cod[],     /* o : innovative code vector                     */
        Word16 h[],       /* i : impulse response of weighted synthesis     */
        /*     filter                                     */
        Word16 y[],       /* o : filtered innovative code                   */
        Word16 sign[],    /* o : sign of 2 pulses                           */
        Flag  *pOverflow  /* o : Flag set when overflow occurs              */
    )
    {
        register Word16 i;
        register Word16 j;
        register Word16 k;
        register Word16 track;
        register Word16 first;
        register Word16 index;
        register Word16 rsign;
        Word16 indx;
        Word16 _sign[NB_PULSE];
        Word16 *p0;
        Word16 *p1;

        const Word16 *pt;

        Word32 s;

        pt = trackTable + subNr + (subNr << 2);

        for (i = 0; i < L_CODE; i++)
        {
            *(cod + i) = 0;
        }

        indx = 0;
        rsign = 0;

        for (k = 0; k < NB_PULSE; k++)
        {
            i = *(codvec + k);  /* read pulse position */
            j = *(dn_sign + i); /* read sign           */

            s = ((Word32)(i * 6554)) >> 15;
            index = (Word16) s; /* index = pos/5 */

            track = i - (5 * index);    /* track = pos%5 */

            first = *(pt + track);


            if (k == 0)
            {
                track = 0;

                if (first != 0)
                {
                    index += 64;  /* table bit is MSB */
                }
            }
            else
            {
                track = 1;
                index <<= 3;
            }

            if (j > 0)
            {
                *(cod + i) = 8191;
                *(_sign + k) = 32767;
                rsign += (1 << track);
            }
            else
            {
                *(cod + i) = ~(8192) + 1;
                *(_sign + k) = (Word16)(~(32768) + 1);
            }

            indx += index;
        }

        *sign = rsign;

        p0 = h - *codvec;
        p1 = h - *(codvec + 1);

        for (i = 0; i < L_CODE; i++)
        {
            s = 0;
            s =
                L_mult(
                    *p0++,
                    *_sign,
                    pOverflow);

            s =
                L_mac(
                    s,
                    *p1++,
                    *(_sign + 1),
                    pOverflow);

            *(y + i) =
                pv_round(
                    s,
                    pOverflow);
        }

        return(indx);
    }

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

    /*
    ------------------------------------------------------------------------------
     FUNCTION NAME: Test_build_code
    ------------------------------------------------------------------------------
     INPUT AND OUTPUT DEFINITIONS

     Inputs:
        subNr = subframe number (Word16)
        codvec = vector containing the position of pulses (Word16)
        dn_sign = vector containing the sign of pulses (Word16)
        cod = innovative code vector (Word16)
        h = vector containing the impulse response of the weighted
            synthesis filter (Word16)
        y = vector containing the filtered innovative code (Word16)
        sign = vector containing the sign of 2 pulses (Word16)

     Outputs:
        cod vector contains the new innovative code
        y vector contains the new filtered innovative code
        sign vector contains the sign of 2 pulses

     Returns:
        indx = codebook index (Word16)

     Global Variables Used:
        None

     Local Variables Needed:
        trackTable = table used for tracking codewords (Word16)

    ------------------------------------------------------------------------------
     FUNCTION DESCRIPTION

     This function provides external access to the local function build_code.

    ------------------------------------------------------------------------------
     REQUIREMENTS

     None

    ------------------------------------------------------------------------------
     REFERENCES

     [1] c2_9pf.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001

    ------------------------------------------------------------------------------
     PSEUDO-CODE

     CALL build_code ( subNr = subNr
               codvec = codvec
               dn_sign = dn_sign
               cod = cod
               h = h
               y = y
               sign = sign )
       MODIFYING(nothing)
       RETURNING(indx)

    ------------------------------------------------------------------------------
     RESOURCES USED [optional]

     When the code is written for a specific target processor the
     the resources used should be documented below.

     HEAP MEMORY USED: x bytes

     STACK MEMORY USED: x bytes

     CLOCK CYCLES: (cycle count equation for this function) + (variable
                    used to represent cycle count for each subroutine
                    called)
         where: (cycle count variable) = cycle count for [subroutine
                                         name]

    ------------------------------------------------------------------------------
     CAUTION [optional]
     [State any special notes, constraints or cautions for users of this function]

    ------------------------------------------------------------------------------
    */

    Word16 Test_build_code(
        Word16 subNr,      /* i : subframe number                            */
        Word16 codvec[],   /* i : position of pulses                         */
        Word16 dn_sign[],  /* i : sign of pulses                             */
        Word16 cod[],      /* o : innovative code vector                     */
        Word16 h[],        /* i : impulse response of weighted synthesis     */
        /*     filter                                     */
        Word16 y[],        /* o : filtered innovative code                   */
        Word16 sign[],     /* o : sign of 2 pulses                           */
        Flag   * pOverflow /* o : Flag set when overflow occurs              */
    )
    {
        Word16  test_index;

        /*----------------------------------------------------------------------------
         CALL build_code ( subNr = subNr
                   codvec = codvec
                   dn_sign = dn_sign
                   cod = cod
                   h = h
                   y = y
                   sign = sign )
           MODIFYING(nothing)
           RETURNING(indx)
        ----------------------------------------------------------------------------*/
        test_index =
            build_code(
                subNr,
                codvec,
                dn_sign,
                cod,
                h,
                y,
                sign,
                pOverflow);

        return(test_index);
    }

#ifdef __cplusplus
}
#endif