/*
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* Copyright 1992 by Jutta Degener and Carsten Bormann, Technische
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* Universitaet Berlin. See the accompanying file "COPYRIGHT" for
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* details. THERE IS ABSOLUTELY NO WARRANTY FOR THIS SOFTWARE.
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*/
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/* $Header: /tmp_amd/presto/export/kbs/jutta/src/gsm/RCS/decode.c,v 1.1 1992/10/28 00:15:50 jutta Exp $ */
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#include <stdio.h>
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#include "private.h"
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#include "gsm.h"
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#include "proto.h"
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/*
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* 4.3 FIXED POINT IMPLEMENTATION OF THE RPE-LTP DECODER
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*/
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static void Postprocessing P2((S,s),
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struct gsm_state * S,
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register word * s)
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{
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register int k;
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register word msr = S->msr;
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register longword ltmp; /* for GSM_ADD */
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register word tmp;
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for (k = 160; k--; s++) {
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tmp = GSM_MULT_R( msr, 28180 );
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msr = GSM_ADD(*s, tmp); /* Deemphasis */
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*s = GSM_ADD(msr, msr) & 0xFFF8; /* Truncation & Upscaling */
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}
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S->msr = msr;
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}
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void Gsm_Decoder P8((S,LARcr, Ncr,bcr,Mcr,xmaxcr,xMcr,s),
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struct gsm_state * S,
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word * LARcr, /* [0..7] IN */
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word * Ncr, /* [0..3] IN */
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word * bcr, /* [0..3] IN */
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word * Mcr, /* [0..3] IN */
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word * xmaxcr, /* [0..3] IN */
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word * xMcr, /* [0..13*4] IN */
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word * s) /* [0..159] OUT */
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{
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int j, k;
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word erp[40], wt[160];
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word * drp = S->dp0 + 120;
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for (j=0; j <= 3; j++, xmaxcr++, bcr++, Ncr++, Mcr++, xMcr += 13) {
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Gsm_RPE_Decoding( S, *xmaxcr, *Mcr, xMcr, erp );
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Gsm_Long_Term_Synthesis_Filtering( S, *Ncr, *bcr, erp, drp );
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for (k = 0; k <= 39; k++) wt[ j * 40 + k ] = drp[ k ];
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}
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Gsm_Short_Term_Synthesis_Filter( S, LARcr, wt, s );
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Postprocessing(S, s);
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}
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