/* * 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: /home/kbs/jutta/src/gsm/gsm-1.0/src/RCS/rpe.c,v 1.3 1994/05/10 20:18:46 jutta Exp $ */#include <stdio.h>#include <assert.h>#include "private.h"#include "gsm.h"#include "proto.h"/*  4.2.13 .. 4.2.17  RPE ENCODING SECTION *//* 4.2.13 */static void Weighting_filter P2((e, x),	register word	* e,		/* signal [-5..0.39.44]	IN  */	word		* x		/* signal [0..39]	OUT */)/* *  The coefficients of the weighting filter are stored in a table *  (see table 4.4).  The following scaling is used: * *	H[0..10] = integer( real_H[ 0..10] * 8192 );  */{	/* word			wt[ 50 ]; */	register longword	L_result;	register int		k /* , i */ ;	/*  Initialization of a temporary working array wt[0...49]	 */	/* for (k =  0; k <=  4; k++) wt[k] = 0;	 * for (k =  5; k <= 44; k++) wt[k] = *e++;	 * for (k = 45; k <= 49; k++) wt[k] = 0;	 *	 *  (e[-5..-1] and e[40..44] are allocated by the caller,	 *  are initially zero and are not written anywhere.)	 */	e -= 5;	/*  Compute the signal x[0..39]	 */ 	for (k = 0; k <= 39; k++) {		L_result = 8192 >> 1;		/* for (i = 0; i <= 10; i++) {		 *	L_temp   = GSM_L_MULT( wt[k+i], gsm_H[i] );		 *	L_result = GSM_L_ADD( L_result, L_temp );		 * }		 */#undef	STEP#define	STEP( i, H )	(e[ k + i ] * (longword)H)		/*  Every one of these multiplications is done twice --		 *  but I don't see an elegant way to optimize this. 		 *  Do you?		 */#ifdef	STUPID_COMPILER		L_result += STEP(	0, 	-134 ) ;		L_result += STEP(	1, 	-374 )  ;	               /* + STEP(	2, 	0    )  */		L_result += STEP(	3, 	2054 ) ;		L_result += STEP(	4, 	5741 ) ;		L_result += STEP(	5, 	8192 ) ;		L_result += STEP(	6, 	5741 ) ;		L_result += STEP(	7, 	2054 ) ;	 	       /* + STEP(	8, 	0    )  */		L_result += STEP(	9, 	-374 ) ;		L_result += STEP(	10, 	-134 ) ;#else		L_result +=		  STEP(	0, 	-134 ) 		+ STEP(	1, 	-374 ) 	     /* + STEP(	2, 	0    )  */		+ STEP(	3, 	2054 ) 		+ STEP(	4, 	5741 ) 		+ STEP(	5, 	8192 ) 		+ STEP(	6, 	5741 ) 		+ STEP(	7, 	2054 ) 	     /* + STEP(	8, 	0    )  */		+ STEP(	9, 	-374 ) 		+ STEP(10, 	-134 )		;#endif		/* L_result = GSM_L_ADD( L_result, L_result ); (* scaling(x2) *)		 * L_result = GSM_L_ADD( L_result, L_result ); (* scaling(x4) *)		 *		 * x[k] = SASR( L_result, 16 );		 */		/* 2 adds vs. >>16 => 14, minus one shift to compensate for		 * those we lost when replacing L_MULT by '*'.		 */		L_result = SASR( L_result, 13 );		x[k] =  (  L_result < MIN_WORD ? MIN_WORD			: (L_result > MAX_WORD ? MAX_WORD : L_result ));	}}/* 4.2.14 */static void RPE_grid_selection P3((x,xM,Mc_out),	word		* x,		/* [0..39]		IN  */ 	word		* xM,		/* [0..12]		OUT */	word		* Mc_out	/*			OUT */)/* *  The signal x[0..39] is used to select the RPE grid which is *  represented by Mc. */{	/* register word	temp1;	*/	register int		/* m, */  i;	register longword	L_result, L_temp;	longword		EM;	/* xxx should be L_EM? */	word			Mc;	longword		L_common_0_3;	EM = 0;	Mc = 0;	/* for (m = 0; m <= 3; m++) {	 *	L_result = 0;	 *	 *	 *	for (i = 0; i <= 12; i++) {	 *	 *		temp1    = SASR( x[m + 3*i], 2 );	 *	 *		assert(temp1 != MIN_WORD);	 *	 *		L_temp   = GSM_L_MULT( temp1, temp1 );	 *		L_result = GSM_L_ADD( L_temp, L_result );	 *	}	 * 	 *	if (L_result > EM) {	 *		Mc = m;	 *		EM = L_result;	 *	}	 * }	 */#undef	STEP#define	STEP( m, i )		L_temp = SASR( x[m + 3 * i], 2 );	\				L_result += L_temp * L_temp;	/* common part of 0 and 3 */	L_result = 0;	STEP( 0, 1 ); STEP( 0, 2 ); STEP( 0, 3 ); STEP( 0, 4 );	STEP( 0, 5 ); STEP( 0, 6 ); STEP( 0, 7 ); STEP( 0, 8 );	STEP( 0, 9 ); STEP( 0, 10); STEP( 0, 11); STEP( 0, 12);	L_common_0_3 = L_result;	/* i = 0 */	STEP( 0, 0 );	L_result <<= 1;	/* implicit in L_MULT */	EM = L_result;	/* i = 1 */	L_result = 0;	STEP( 1, 0 );	STEP( 1, 1 ); STEP( 1, 2 ); STEP( 1, 3 ); STEP( 1, 4 );	STEP( 1, 5 ); STEP( 1, 6 ); STEP( 1, 7 ); STEP( 1, 8 );	STEP( 1, 9 ); STEP( 1, 10); STEP( 1, 11); STEP( 1, 12);	L_result <<= 1;	if (L_result > EM) {		Mc = 1;	 	EM = L_result;	}	/* i = 2 */	L_result = 0;	STEP( 2, 0 );	STEP( 2, 1 ); STEP( 2, 2 ); STEP( 2, 3 ); STEP( 2, 4 );	STEP( 2, 5 ); STEP( 2, 6 ); STEP( 2, 7 ); STEP( 2, 8 );	STEP( 2, 9 ); STEP( 2, 10); STEP( 2, 11); STEP( 2, 12);	L_result <<= 1;	if (L_result > EM) {		Mc = 2;	 	EM = L_result;	}	/* i = 3 */	L_result = L_common_0_3;	STEP( 3, 12 );	L_result <<= 1;	if (L_result > EM) {		Mc = 3;	 	EM = L_result;	}	/**/	/*  Down-sampling by a factor 3 to get the selected xM[0..12]	 *  RPE sequence.	 */	for (i = 0; i <= 12; i ++) xM[i] = x[Mc + 3*i];	*Mc_out = Mc;}/* 4.12.15 */static void APCM_quantization_xmaxc_to_exp_mant P3((xmaxc,exp_out,mant_out),	word		xmaxc,		/* IN 	*/	word		* exp_out,	/* OUT	*/	word		* mant_out )	/* OUT  */{	word	exp, mant;	/* Compute exponent and mantissa of the decoded version of xmaxc	 */	exp = 0;	if (xmaxc > 15) exp = SASR(xmaxc, 3) - 1;	mant = xmaxc - (exp << 3);	if (mant == 0) {		exp  = -4;		mant = 7;	}	else {		while (mant <= 7) {			mant = mant << 1 | 1;			exp--;		}		mant -= 8;	}	assert( exp  >= -4 && exp <= 6 );	assert( mant >= 0 && mant <= 7 );	*exp_out  = exp;	*mant_out = mant;}static void APCM_quantization P5((xM,xMc,mant_out,exp_out,xmaxc_out),	word		* xM,		/* [0..12]		IN	*/	word		* xMc,		/* [0..12]		OUT	*/	word		* mant_out,	/* 			OUT	*/	word		* exp_out,	/*			OUT	*/	word		* xmaxc_out	/*			OUT	*/){	int	i, itest;	word	xmax, xmaxc, temp, temp1, temp2;	word	exp, mant;	/*  Find the maximum absolute value xmax of xM[0..12].	 */	xmax = 0;	for (i = 0; i <= 12; i++) {		temp = xM[i];		temp = GSM_ABS(temp);		if (temp > xmax) xmax = temp;	}	/*  Qantizing and coding of xmax to get xmaxc.	 */	exp   = 0;	temp  = SASR( xmax, 9 );	itest = 0;	for (i = 0; i <= 5; i++) {		itest |= (temp <= 0);		temp = SASR( temp, 1 );		assert(exp <= 5);		if (itest == 0) exp++;		/* exp = add (exp, 1) */	}	assert(exp <= 6 && exp >= 0);	temp = exp + 5;	assert(temp <= 11 && temp >= 0);	xmaxc = gsm_add( SASR(xmax, temp), exp << 3 );	/*   Quantizing and coding of the xM[0..12] RPE sequence	 *   to get the xMc[0..12]	 */	APCM_quantization_xmaxc_to_exp_mant( xmaxc, &exp, &mant );	/*  This computation uses the fact that the decoded version of xmaxc	 *  can be calculated by using the exponent and the mantissa part of	 *  xmaxc (logarithmic table).	 *  So, this method avoids any division and uses only a scaling	 *  of the RPE samples by a function of the exponent.  A direct 	 *  multiplication by the inverse of the mantissa (NRFAC[0..7]	 *  found in table 4.5) gives the 3 bit coded version xMc[0..12]	 *  of the RPE samples.	 */	/* Direct computation of xMc[0..12] using table 4.5	 */	assert( exp <= 4096 && exp >= -4096);	assert( mant >= 0 && mant <= 7 ); 	temp1 = 6 - exp;		/* normalization by the exponent */	temp2 = gsm_NRFAC[ mant ];  	/* inverse mantissa 		 */	for (i = 0; i <= 12; i++) {		assert(temp1 >= 0 && temp1 < 16);		temp = xM[i] << temp1;		temp = GSM_MULT( temp, temp2 );		temp = SASR(temp, 12);		xMc[i] = temp + 4;		/* see note below */	}	/*  NOTE: This equation is used to make all the xMc[i] positive.	 */	*mant_out  = mant;	*exp_out   = exp;	*xmaxc_out = xmaxc;}/* 4.2.16 */static void APCM_inverse_quantization P4((xMc,mant,exp,xMp),	register word	* xMc,	/* [0..12]			IN 	*/	word		mant,	word		exp,	register word	* xMp)	/* [0..12]			OUT 	*//*  *  This part is for decoding the RPE sequence of coded xMc[0..12] *  samples to obtain the xMp[0..12] array.  Table 4.6 is used to get *  the mantissa of xmaxc (FAC[0..7]). */{	int	i;	word	temp, temp1, temp2, temp3;	longword	ltmp;	assert( mant >= 0 && mant <= 7 ); 	temp1 = gsm_FAC[ mant ];	/* see 4.2-15 for mant */	temp2 = gsm_sub( 6, exp );	/* see 4.2-15 for exp  */	temp3 = gsm_asl( 1, gsm_sub( temp2, 1 ));	for (i = 13; i--;) {		assert( *xMc <= 7 && *xMc >= 0 ); 	/* 3 bit unsigned */		/* temp = gsm_sub( *xMc++ << 1, 7 ); */		temp = (*xMc++ << 1) - 7;	        /* restore sign   */		assert( temp <= 7 && temp >= -7 ); 	/* 4 bit signed   */		temp <<= 12;				/* 16 bit signed  */		temp = GSM_MULT_R( temp1, temp );		temp = GSM_ADD( temp, temp3 );		*xMp++ = gsm_asr( temp, temp2 );	}}/* 4.2.17 */static void RPE_grid_positioning P3((Mc,xMp,ep),	word		Mc,		/* grid position	IN	*/	register word	* xMp,		/* [0..12]		IN	*/	register word	* ep		/* [0..39]		OUT	*/)/* *  This procedure computes the reconstructed long term residual signal *  ep[0..39] for the LTP analysis filter.  The inputs are the Mc *  which is the grid position selection and the xMp[0..12] decoded *  RPE samples which are upsampled by a factor of 3 by inserting zero *  values. */{	int	i = 13;	assert(0 <= Mc && Mc <= 3);        switch (Mc) {                case 3: *ep++ = 0;                case 2:  do {                                *ep++ = 0;                case 1:         *ep++ = 0;                case 0:         *ep++ = *xMp++;                         } while (--i);        }        while (++Mc < 4) *ep++ = 0;	/*	int i, k;	for (k = 0; k <= 39; k++) ep[k] = 0;	for (i = 0; i <= 12; i++) {		ep[ Mc + (3*i) ] = xMp[i];	}	*/}/* 4.2.18 *//*  This procedure adds the reconstructed long term residual signal *  ep[0..39] to the estimated signal dpp[0..39] from the long term *  analysis filter to compute the reconstructed short term residual *  signal dp[-40..-1]; also the reconstructed short term residual *  array dp[-120..-41] is updated. */#if 0	/* Has been inlined in code.c */void Gsm_Update_of_reconstructed_short_time_residual_signal P3((dpp, ep, dp),	word	* dpp,		/* [0...39]	IN	*/	word	* ep,		/* [0...39]	IN	*/	word	* dp)		/* [-120...-1]  IN/OUT 	*/{	int 		k;	for (k = 0; k <= 79; k++) 		dp[ -120 + k ] = dp[ -80 + k ];	for (k = 0; k <= 39; k++)		dp[ -40 + k ] = gsm_add( ep[k], dpp[k] );}#endif	/* Has been inlined in code.c */void Gsm_RPE_Encoding P5((S,e,xmaxc,Mc,xMc),	struct gsm_state * S,	word	* e,		/* -5..-1][0..39][40..44	IN/OUT  */	word	* xmaxc,	/* 				OUT */	word	* Mc,		/* 			  	OUT */	word	* xMc)		/* [0..12]			OUT */{	word	x[40];	word	xM[13], xMp[13];	word	mant, exp;	Weighting_filter(e, x);	RPE_grid_selection(x, xM, Mc);	APCM_quantization(	xM, xMc, &mant, &exp, xmaxc);	APCM_inverse_quantization(  xMc,  mant,  exp, xMp);	RPE_grid_positioning( *Mc, xMp, e );}void Gsm_RPE_Decoding P5((S, xmaxcr, Mcr, xMcr, erp),	struct gsm_state	* S,	word 		xmaxcr,	word		Mcr,	word		* xMcr,  /* [0..12], 3 bits 		IN	*/	word		* erp	 /* [0..39]			OUT 	*/){	word	exp, mant;	word	xMp[ 13 ];	APCM_quantization_xmaxc_to_exp_mant( xmaxcr, &exp, &mant );	APCM_inverse_quantization( xMcr, mant, exp, xMp );	RPE_grid_positioning( Mcr, xMp, erp );}