/*
 * Copyright 1992 by Jutta Degener and Carsten Bormann, Technische
 * Universitaet Berlin.  See the accompanying file "COPYRIGHT" for
 * details.  THERE IS ABSOLUTELY NO WARRANTY FOR THIS SOFTWARE.
 */

/* $Id: decode.c,v 1.4 1998/09/09 21:06:43 gert Exp $ */

#include <stdio.h>

#include  "private.h"
#include  "gsm.h"
#include  "proto.h"

/*
 *  4.3 FIXED POINT IMPLEMENTATION OF THE RPE-LTP DECODER
 */

static void Postprocessing P2((S,s),
     struct gsm_state    * S,
     register word       * s)
{
     register int        k;
     register word       msr = S->msr;
     register longword   ltmp;     /* for GSM_ADD */
     register word       tmp;

     for (k = 160; k--; s++) {
          tmp = GSM_MULT_R( msr, 28180 );
          msr = GSM_ADD(*s, tmp);          /* Deemphasis         */
          *s  = GSM_ADD(msr, msr) & 0xFFF8;  /* Truncation & Upscaling */
     }
     S->msr = msr;
}

void Gsm_Decoder P8((S,LARcr, Ncr,bcr,Mcr,xmaxcr,xMcr,s),
     struct gsm_state    * S,

     word      * LARcr,  /* [0..7]      IN   */

     word      * Ncr,         /* [0..3]           IN   */
     word      * bcr,         /* [0..3]      IN   */
     word      * Mcr,         /* [0..3]           IN   */
     word      * xmaxcr, /* [0..3]      IN   */
     word      * xMcr,        /* [0..13*4]        IN   */

     word      * s)      /* [0..159]         OUT  */
{
     int       j, k;
     word      erp[40], wt[160];
     word      * drp = S->dp0 + 120;

     for (j=0; j <= 3; j++, xmaxcr++, bcr++, Ncr++, Mcr++, xMcr += 13) {

          Gsm_RPE_Decoding( S, *xmaxcr, *Mcr, xMcr, erp );
          Gsm_Long_Term_Synthesis_Filtering( S, *Ncr, *bcr, erp, drp );

          for (k = 0; k <= 39; k++) wt[ j * 40 + k ] =  drp[ k ];
     }

     Gsm_Short_Term_Synthesis_Filter( S, LARcr, wt, s );
     Postprocessing(S, s);
}
