cor_h.c

/* ------------------------------------------------------------------
 * Copyright (C) 1998-2009 PacketVideo
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
 * express or implied.
 * See the License for the specific language governing permissions
 * and limitations under the License.
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/****************************************************************************************
Portions of this file are derived from the following 3GPP standard:

    3GPP TS 26.073
    ANSI-C code for the Adaptive Multi-Rate (AMR) speech codec
    Available from http://www.3gpp.org

(C) 2004, 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TTA, TTC)
Permission to distribute, modify and use this file under the standard license
terms listed above has been obtained from the copyright holder.
****************************************************************************************/
/*
------------------------------------------------------------------------------



 Filename: cor_h.cpp

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

/*----------------------------------------------------------------------------
; INCLUDES
----------------------------------------------------------------------------*/
#include "cnst.h"
#include "cor_h.h"
#include "basicop_malloc.h"
#include "inv_sqrt.h"
#include "basic_op.h"

/*----------------------------------------------------------------------------
; MACROS
; Define module specific macros here
----------------------------------------------------------------------------*/

/*----------------------------------------------------------------------------
; DEFINES
; Include all pre-processor statements here. Include conditional
; compile variables also.
----------------------------------------------------------------------------*/

/*----------------------------------------------------------------------------
; LOCAL FUNCTION DEFINITIONS
; Function Prototype declaration
----------------------------------------------------------------------------*/

/*----------------------------------------------------------------------------
; LOCAL STORE/BUFFER/POINTER DEFINITIONS
; Variable declaration - defined here and used outside this module
----------------------------------------------------------------------------*/

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

 Inputs:
    h = vector containing the impulse response of the weighted synthesis
        filter; vector contents are of type Word16; vector length is
        2 * L_SUBFR
    sign = vector containing the sign information for the correlation
           values; vector contents are of type Word16; vector length is
           L_CODE
    rr = autocorrelation matrix; matrix contents are of type Word16;
         matrix dimension is L_CODE by L_CODE

 Outputs:
    rr contents are the newly calculated autocorrelation values

 Returns:
    None

 Global Variables Used:
    None

 Local Variables Needed:
    None

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

 This function computes correlations of the impulse response (h) needed for
 the codebook search, and includes the sign information into the correlations.

 The correlations are given by:
    rr[i][j] = sum_{n=i}^{L-1} h[n-i] h[n-j];   i>=j; i,j=0,...,L-1

 The sign information is included by:
    rr[i][j] = rr[i][j]*sign[i]*sign[j]

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

 None

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

 cor_h.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001

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

void cor_h (
    Word16 h[],         // (i) : impulse response of weighted synthesis
                                 filter
    Word16 sign[],      // (i) : sign of d[n]
    Word16 rr[][L_CODE] // (o) : matrix of autocorrelation
)
{
    Word16 i, j, k, dec, h2[L_CODE];
    Word32 s;

    // Scaling for maximum precision

    s = 2;
    for (i = 0; i < L_CODE; i++)
        s = L_mac (s, h[i], h[i]);

    j = sub (extract_h (s), 32767);
    if (j == 0)
    {
        for (i = 0; i < L_CODE; i++)
        {
            h2[i] = shr (h[i], 1);
        }
    }
    else
    {
        s = L_shr (s, 1);
        k = extract_h (L_shl (Inv_sqrt (s), 7));
        k = mult (k, 32440);                     // k = 0.99*k

        for (i = 0; i < L_CODE; i++)
        {
            h2[i] = pv_round (L_shl (L_mult (h[i], k), 9));
        }
    }

    // build matrix rr[]
    s = 0;
    i = L_CODE - 1;
    for (k = 0; k < L_CODE; k++, i--)
    {
        s = L_mac (s, h2[k], h2[k]);
        rr[i][i] = pv_round (s);
    }

    for (dec = 1; dec < L_CODE; dec++)
    {
        s = 0;
        j = L_CODE - 1;
        i = sub (j, dec);
        for (k = 0; k < (L_CODE - dec); k++, i--, j--)
        {
            s = L_mac (s, h2[k], h2[k + dec]);
            rr[j][i] = mult (pv_round (s), mult (sign[i], sign[j]));
            rr[i][j] = rr[j][i];
        }
    }
}

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

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

void cor_h(
    Word16 h[],          /* (i) : impulse response of weighted synthesis
                                  filter                                  */
    Word16 sign[],       /* (i) : sign of d[n]                            */
    Word16 rr[][L_CODE], /* (o) : matrix of autocorrelation               */
    Flag  *pOverflow
)
{
    register Word16 i;
    register Word16 dec;

    Word16 h2[L_CODE];
    Word32 s;
    Word32 s2;
    Word16 tmp1;
    Word16 tmp2;
    Word16 tmp11;
    Word16 tmp22;

    Word16 *p_h;
    Word16 *p_h2;
    Word16 *rr1;
    Word16 *rr2;
    Word16 *rr3;
    Word16 *p_rr_ref1;
    Word16 *p_sign1;
    Word16 *p_sign2;

    /* Scaling for maximum precision */

    /* Initialize accumulator to 1 since left shift happens    */
    /* after the accumulation of the sum of squares (original  */
    /* code initialized s to 2)                                */
    s = 1;
    p_h = h;

    for (i = (L_CODE >> 1); i != 0 ; i--)
    {
        tmp1 = *(p_h++);
        s = amrnb_fxp_mac_16_by_16bb((Word32) tmp1, (Word32) tmp1, s);
        tmp1 = *(p_h++);
        s = amrnb_fxp_mac_16_by_16bb((Word32) tmp1, (Word32) tmp1, s);

    }

    s <<= 1;

    if (s & MIN_32)
    {
        p_h2 = h2;
        p_h  = h;

        for (i = (L_CODE >> 1); i != 0; i--)
        {
            *(p_h2++) =  *(p_h++)  >> 1;
            *(p_h2++) =  *(p_h++)  >> 1;
        }
    }
    else
    {

        s >>= 1;

        s = Inv_sqrt(s, pOverflow);

        if (s < (Word32) 0x00ffffffL)
        {
            /* k = 0.99*k */
            dec = (Word16)(((s >> 9) * 32440) >> 15);
        }
        else
        {
            dec = 32440;  /* 0.99 */
        }

        p_h  = h;
        p_h2 = h2;

        for (i = (L_CODE >> 1); i != 0; i--)
        {
            *(p_h2++) = (Word16)((amrnb_fxp_mac_16_by_16bb((Word32) * (p_h++), (Word32) dec, 0x020L)) >> 6);
            *(p_h2++) = (Word16)((amrnb_fxp_mac_16_by_16bb((Word32) * (p_h++), (Word32) dec, 0x020L)) >> 6);
        }
    }
    /* build matrix rr[] */

    s = 0;

    p_h2 = h2;

    rr1 = &rr[L_CODE-1][L_CODE-1];

    for (i = L_CODE >> 1; i != 0 ; i--)
    {
        tmp1   = *(p_h2++);
        s = amrnb_fxp_mac_16_by_16bb((Word32) tmp1, (Word32) tmp1, s);
        *rr1 = (Word16)((s + 0x00004000L) >> 15);
        rr1 -= (L_CODE + 1);
        tmp1   = *(p_h2++);
        s = amrnb_fxp_mac_16_by_16bb((Word32) tmp1, (Word32) tmp1, s);
        *rr1 = (Word16)((s + 0x00004000L) >> 15);
        rr1 -= (L_CODE + 1);
    }


    p_rr_ref1 = rr[L_CODE-1];

    for (dec = 1; dec < L_CODE; dec += 2)
    {
        rr1 = &p_rr_ref1[L_CODE-1-dec];

        rr2 = &rr[L_CODE-1-dec][L_CODE-1];
        rr3 = &rr[L_CODE-1-(dec+1)][L_CODE-1];

        s  = 0;
        s2 = 0;

        p_sign1 = &sign[L_CODE - 1];
        p_sign2 = &sign[L_CODE - 1 - dec];

        p_h2 = h2;
        p_h  = &h2[dec];

        for (i = (L_CODE - dec - 1); i != 0 ; i--)
        {
            s = amrnb_fxp_mac_16_by_16bb((Word32) * (p_h2), (Word32) * (p_h++), s);
            s2 = amrnb_fxp_mac_16_by_16bb((Word32) * (p_h2++), (Word32) * (p_h), s2);

            tmp1  = (Word16)((s + 0x00004000L) >> 15);
            tmp11 = (Word16)((s2 + 0x00004000L) >> 15);

            tmp2  = ((Word32) * (p_sign1) * *(p_sign2--)) >> 15;
            tmp22 = ((Word32) * (p_sign1--) * *(p_sign2)) >> 15;

            *rr2 = ((Word32) tmp1 * tmp2) >> 15;
            *(rr1--) = *rr2;
            *rr1 = ((Word32) tmp11 * tmp22) >> 15;
            *rr3 = *rr1;

            rr1 -= (L_CODE);
            rr2 -= (L_CODE + 1);
            rr3 -= (L_CODE + 1);

        }

        s = amrnb_fxp_mac_16_by_16bb((Word32) * (p_h2), (Word32) * (p_h), s);

        tmp1 = (Word16)((s + 0x00004000L) >> 15);

        tmp2 = ((Word32) * (p_sign1) * *(p_sign2)) >> 15;
        *rr1 = ((Word32) tmp1 * tmp2) >> 15;

        *rr2 = *rr1;

        rr1 -= (L_CODE + 1);
        rr2 -= (L_CODE + 1);

    }

    return;

}