/* * 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. *//* $Header: /cvsroot/linphone/linphone/gsmlib/code.c,v 1.1.1.1 2001/11/19 19:50:11 smorlat Exp $ */#include	"config.h"#ifdef	HAS_STDLIB_H#include	<stdlib.h>#else#	include "proto.h"	extern char	* memcpy P((char *, char *, int));#endif#include	"private.h"#include	"gsm.h"#include	"proto.h"/*  *  4.2 FIXED POINT IMPLEMENTATION OF THE RPE-LTP CODER  */void Gsm_Coder P8((S,s,LARc,Nc,bc,Mc,xmaxc,xMc),	struct gsm_state	* S,	word	* s,	/* [0..159] samples		  	IN	*//* * The RPE-LTD coder works on a frame by frame basis.  The length of * the frame is equal to 160 samples.  Some computations are done * once per frame to produce at the output of the coder the * LARc[1..8] parameters which are the coded LAR coefficients and  * also to realize the inverse filtering operation for the entire * frame (160 samples of signal d[0..159]).  These parts produce at * the output of the coder: */	word	* LARc,	/* [0..7] LAR coefficients		OUT	*//* * Procedure 4.2.11 to 4.2.18 are to be executed four times per * frame.  That means once for each sub-segment RPE-LTP analysis of * 40 samples.  These parts produce at the output of the coder: */	word	* Nc,	/* [0..3] LTP lag			OUT 	*/	word	* bc,	/* [0..3] coded LTP gain		OUT 	*/	word	* Mc,	/* [0..3] RPE grid selection		OUT     */	word	* xmaxc,/* [0..3] Coded maximum amplitude	OUT	*/	word	* xMc	/* [13*4] normalized RPE samples	OUT	*/){	int	k;	word	* dp  = S->dp0 + 120;	/* [ -120...-1 ] */	word	* dpp = dp;		/* [ 0...39 ]	 */	static word e[50];	word	so[160];	Gsm_Preprocess			(S, s, so);	Gsm_LPC_Analysis		(S, so, LARc);	Gsm_Short_Term_Analysis_Filter	(S, LARc, so);	for (k = 0; k <= 3; k++, xMc += 13) {		Gsm_Long_Term_Predictor	( S,					 so+k*40, /* d      [0..39] IN	*/					 dp,	  /* dp  [-120..-1] IN	*/					e + 5,	  /* e      [0..39] OUT	*/					dpp,	  /* dpp    [0..39] OUT */					 Nc++,					 bc++);		Gsm_RPE_Encoding	( S,					e + 5,	/* e	  ][0..39][ IN/OUT */					  xmaxc++, Mc++, xMc );		/*		 * Gsm_Update_of_reconstructed_short_time_residual_signal		 *			( dpp, e + 5, dp );		 */		{ register int i;		  register longword ltmp;		  for (i = 0; i <= 39; i++)			dp[ i ] = GSM_ADD( e[5 + i], dpp[i] );		}		dp  += 40;		dpp += 40;	}	(void)memcpy( (char *)S->dp0, (char *)(S->dp0 + 160),		120 * sizeof(*S->dp0) );}