{	return (fmult(state_ptr->a[1] >> 2, state_ptr->sr[1]) +	    fmult(state_ptr->a[0] >> 2, state_ptr->sr[0]));}/* * step_size() * * computes the quantization step size of the adaptive quantizer. * */int  step_size (G72x_STATE *state_ptr){	int		y;	int		dif;	int		al;	if (state_ptr->ap >= 256)		return (state_ptr->yu);	else {		y = state_ptr->yl >> 6;		dif = state_ptr->yu - y;		al = state_ptr->ap >> 2;		if (dif > 0)			y += (dif * al) >> 6;		else if (dif < 0)			y += (dif * al + 0x3F) >> 6;		return (y);	}}/* * quantize() * * Given a raw sample, 'd', of the difference signal and a * quantization step size scale factor, 'y', this routine returns the * ADPCM codeword to which that sample gets quantized.  The step * size scale factor division operation is done in the log base 2 domain * as a subtraction. */int quantize(	int		d,	/* Raw difference signal sample */	int		y,	/* Step size multiplier */	short	*table,	/* quantization table */	int		size)	/* table size of short integers */{	short		dqm;	/* Magnitude of 'd' */	short		exp;	/* Integer part of base 2 log of 'd' */	short		mant;	/* Fractional part of base 2 log */	short		dl;	/* Log of magnitude of 'd' */	short		dln;	/* Step size scale factor normalized log */	int		i;	/*	 * LOG	 *	 * Compute base 2 log of 'd', and store in 'dl'.	 */	dqm = abs(d);	exp = quan(dqm >> 1, power2, 15);	mant = ((dqm << 7) >> exp) & 0x7F;	/* Fractional portion. */	dl = (exp << 7) + mant;	/*	 * SUBTB	 *	 * "Divide" by step size multiplier.	 */	dln = dl - (y >> 2);	/*	 * QUAN	 *	 * Obtain codword i for 'd'.	 */	i = quan(dln, table, size);	if (d < 0)			/* take 1's complement of i */		return ((size << 1) + 1 - i);	else if (i == 0)		/* take 1's complement of 0 */		return ((size << 1) + 1); /* new in 1988 */	else		return (i);}/* * reconstruct() * * Returns reconstructed difference signal 'dq' obtained from * codeword 'i' and quantization step size scale factor 'y'. * Multiplication is performed in log base 2 domain as addition. */intreconstruct(	int		sign,	/* 0 for non-negative value */	int		dqln,	/* G.72x codeword */	int		y)	/* Step size multiplier */{	short		dql;	/* Log of 'dq' magnitude */	short		dex;	/* Integer part of log */	short		dqt;	short		dq;	/* Reconstructed difference signal sample */	dql = dqln + (y >> 2);	/* ADDA */	if (dql < 0) {		return ((sign) ? -0x8000 : 0);	} else {		/* ANTILOG */		dex = (dql >> 7) & 15;		dqt = 128 + (dql & 127);		dq = (dqt << 7) >> (14 - dex);		return ((sign) ? (dq - 0x8000) : dq);	}}/* * update() * * updates the state variables for each output code */voidupdate(	int		code_size,	/* distinguish 723_40 with others */	int		y,		/* quantizer step size */	int		wi,		/* scale factor multiplier */	int		fi,		/* for long/short term energies */	int		dq,		/* quantized prediction difference */	int		sr,		/* reconstructed signal */	int		dqsez,		/* difference from 2-pole predictor */	G72x_STATE *state_ptr)	/* coder state pointer */{	int		cnt;	short		mag, exp;	/* Adaptive predictor, FLOAT A */	short		a2p = 0;	/* LIMC */	short		a1ul;		/* UPA1 */	short		pks1;		/* UPA2 */	short		fa1;	char		tr;		/* tone/transition detector */	short		ylint, thr2, dqthr;	short  		ylfrac, thr1;	short		pk0;	pk0 = (dqsez < 0) ? 1 : 0;	/* needed in updating predictor poles */	mag = dq & 0x7FFF;		/* prediction difference magnitude */	/* TRANS */	ylint = state_ptr->yl >> 15;	/* exponent part of yl */	ylfrac = (state_ptr->yl >> 10) & 0x1F;	/* fractional part of yl */	thr1 = (32 + ylfrac) << ylint;		/* threshold */	thr2 = (ylint > 9) ? 31 << 10 : thr1;	/* limit thr2 to 31 << 10 */	dqthr = (thr2 + (thr2 >> 1)) >> 1;	/* dqthr = 0.75 * thr2 */	if (state_ptr->td == 0)		/* signal supposed voice */		tr = 0;	else if (mag <= dqthr)		/* supposed data, but small mag */		tr = 0;			/* treated as voice */	else				/* signal is data (modem) */		tr = 1;	/*	 * Quantizer scale factor adaptation.	 */	/* FUNCTW & FILTD & DELAY */	/* update non-steady state step size multiplier */	state_ptr->yu = y + ((wi - y) >> 5);	/* LIMB */	if (state_ptr->yu < 544)	/* 544 <= yu <= 5120 */		state_ptr->yu = 544;	else if (state_ptr->yu > 5120)		state_ptr->yu = 5120;	/* FILTE & DELAY */	/* update steady state step size multiplier */	state_ptr->yl += state_ptr->yu + ((-state_ptr->yl) >> 6);	/*	 * Adaptive predictor coefficients.	 */	if (tr == 1) {			/* reset a's and b's for modem signal */		state_ptr->a[0] = 0;		state_ptr->a[1] = 0;		state_ptr->b[0] = 0;		state_ptr->b[1] = 0;		state_ptr->b[2] = 0;		state_ptr->b[3] = 0;		state_ptr->b[4] = 0;		state_ptr->b[5] = 0;	} else {			/* update a's and b's */		pks1 = pk0 ^ state_ptr->pk[0];		/* UPA2 */		/* update predictor pole a[1] */		a2p = state_ptr->a[1] - (state_ptr->a[1] >> 7);		if (dqsez != 0) {			fa1 = (pks1) ? state_ptr->a[0] : -state_ptr->a[0];			if (fa1 < -8191)	/* a2p = function of fa1 */				a2p -= 0x100;			else if (fa1 > 8191)				a2p += 0xFF;			else				a2p += fa1 >> 5;			if (pk0 ^ state_ptr->pk[1])				/* LIMC */				if (a2p <= -12160)					a2p = -12288;				else if (a2p >= 12416)					a2p = 12288;				else					a2p -= 0x80;			else if (a2p <= -12416)				a2p = -12288;			else if (a2p >= 12160)				a2p = 12288;			else				a2p += 0x80;		}		/* TRIGB & DELAY */		state_ptr->a[1] = a2p;		/* UPA1 */		/* update predictor pole a[0] */		state_ptr->a[0] -= state_ptr->a[0] >> 8;		if (dqsez != 0)		{	if (pks1 == 0)				state_ptr->a[0] += 192;			else				state_ptr->a[0] -= 192;			} ;		/* LIMD */		a1ul = 15360 - a2p;		if (state_ptr->a[0] < -a1ul)			state_ptr->a[0] = -a1ul;		else if (state_ptr->a[0] > a1ul)			state_ptr->a[0] = a1ul;		/* UPB : update predictor zeros b[6] */		for (cnt = 0; cnt < 6; cnt++) {			if (code_size == 5)		/* for 40Kbps G.723 */				state_ptr->b[cnt] -= state_ptr->b[cnt] >> 9;			else			/* for G.721 and 24Kbps G.723 */				state_ptr->b[cnt] -= state_ptr->b[cnt] >> 8;			if (dq & 0x7FFF) {			/* XOR */				if ((dq ^ state_ptr->dq[cnt]) >= 0)					state_ptr->b[cnt] += 128;				else					state_ptr->b[cnt] -= 128;			}		}	}	for (cnt = 5; cnt > 0; cnt--)		state_ptr->dq[cnt] = state_ptr->dq[cnt-1];	/* FLOAT A : convert dq[0] to 4-bit exp, 6-bit mantissa f.p. */	if (mag == 0) {		state_ptr->dq[0] = (dq >= 0) ? 0x20 : 0xFC20;	} else {		exp = quan(mag, power2, 15);		state_ptr->dq[0] = (dq >= 0) ?		    (exp << 6) + ((mag << 6) >> exp) :		    (exp << 6) + ((mag << 6) >> exp) - 0x400;	}	state_ptr->sr[1] = state_ptr->sr[0];	/* FLOAT B : convert sr to 4-bit exp., 6-bit mantissa f.p. */	if (sr == 0) {		state_ptr->sr[0] = 0x20;	} else if (sr > 0) {		exp = quan(sr, power2, 15);		state_ptr->sr[0] = (exp << 6) + ((sr << 6) >> exp);	} else if (sr > -32768) {		mag = -sr;		exp = quan(mag, power2, 15);		state_ptr->sr[0] =  (exp << 6) + ((mag << 6) >> exp) - 0x400;	} else		state_ptr->sr[0] = (short) 0xFC20;	/* DELAY A */	state_ptr->pk[1] = state_ptr->pk[0];	state_ptr->pk[0] = pk0;	/* TONE */	if (tr == 1)		/* this sample has been treated as data */		state_ptr->td = 0;	/* next one will be treated as voice */	else if (a2p < -11776)	/* small sample-to-sample correlation */		state_ptr->td = 1;	/* signal may be data */	else				/* signal is voice */		state_ptr->td = 0;	/*	 * Adaptation speed control.	 */	state_ptr->dms += (fi - state_ptr->dms) >> 5;		/* FILTA */	state_ptr->dml += (((fi << 2) - state_ptr->dml) >> 7);	/* FILTB */	if (tr == 1)		state_ptr->ap = 256;	else if (y < 1536)					/* SUBTC */		state_ptr->ap += (0x200 - state_ptr->ap) >> 4;	else if (state_ptr->td == 1)		state_ptr->ap += (0x200 - state_ptr->ap) >> 4;	else if (abs((state_ptr->dms << 2) - state_ptr->dml) >=	    (state_ptr->dml >> 3))		state_ptr->ap += (0x200 - state_ptr->ap) >> 4;	else		state_ptr->ap += (-state_ptr->ap) >> 4;}