RTL271_1/evrcc/code/a2lsp.c

/**********************************************************************
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*******************************************************************/
 
/*======================================================================*/
/*     Enhanced Variable Rate Codec - Bit-Exact C Specification         */
/*     Copyright (C) 1997-1998 Telecommunications Industry Association. */
/*     All rights reserved.                                             */
/*----------------------------------------------------------------------*/
/* Note:  Reproduction and use of this software for the design and      */
/*     development of North American Wideband CDMA Digital              */
/*     Cellular Telephony Standards is authorized by the TIA.           */
/*     The TIA does not authorize the use of this software for any      */
/*     other purpose.                                                   */
/*                                                                      */
/*     The availability of this software does not provide any license   */
/*     by implication, estoppel, or otherwise under any patent rights   */
/*     of TIA member companies or others covering any use of the        */
/*     contents herein.                                                 */
/*                                                                      */
/*     Any copies of this software or derivative works must include     */
/*     this and all other proprietary notices.                          */
/*======================================================================*/
/*  Memory Usage:                                                       */
/*      ROM:                4                                           */
/*      Static/Global RAM:  0                                           */
/*      Stack/Local RAM:    21                                          */
/*----------------------------------------------------------------------*/

/*
 * pctolsp - convert pc   to lsp
 *
 * NOTES: 1. This routine is hardwired for 10th order
 *        2. The routine uses 3 stage uniform grid quantization of lsp.
 */
#include "macro.h"
//#include "mathevrc.h"
#include "dsp_math.h"
#include "mathdp31.h"
#include "mathadv.h"

#define STEPSNUM 4
INT32 interpolation_cos129(INT16);
void a2lsp(INT16 *freq, INT16 *a)
{
	static INT32 LSTEPS[4] =
	{13636520, 6818260, 3409130, 1704565};

	int lspnumber;
	int root, notlast;
	INT32 Ltemp;
	INT32 Lq[11], t[7], s[6];
	INT32 Lprev[2];
	int offset;
	int iswitch;
	INT32 Lfrequency, LastFreq;
	INT32 LSTEP;
	int STEPindex;
	INT16 num;
	INT16 j;
	INT16 scale;
	scale = 5;
	LastFreq = 0;
	t[0] = 0;
	t[1] = L_shr(L_deposit_h(0x1000), scale);
	Lq[0] = t[1];

	/* calculate q[z] and p[z] , they are all stored in q */
	for (j = 1; j < 6; j++)
	{
		Lq[j] = L_add(L_shr(L_deposit_h(a[j - 1]), scale),
					  L_shr(L_deposit_h(a[10 - j]), scale));
		Lq[j] = L_sub(Lq[j], Lq[j - 1]);
	}

	Lq[5] = L_shr(Lq[5], 1);
	offset = 5;
	Lq[1 + offset] = L_add(L_shr(L_deposit_h(sub(a[0], a[9])), scale), Lq[0]);

	for (j = 2; j < 6; j++)
	{
		Lq[j + offset] = L_sub(L_shr(L_deposit_h(a[j - 1]), scale),
							   L_shr(L_deposit_h(a[10 - j]), scale));
		Lq[j + offset] = L_add(Lq[j + offset], Lq[j - 1 + offset]);
	}

	Lq[5 + offset] = L_shr(Lq[5 + offset], 1);
	Lprev[0] = LW_MAX;
	Lprev[1] = LW_MAX;
	lspnumber = 0;
	notlast = TRUE;
	iswitch = 0;
	Lfrequency = 0x00000000L;

	while (notlast)
	{

		root = TRUE;
		if (iswitch)
			offset = 5;
		else
			offset = 0;

		STEPindex = 0;			/* Start with low resolution grid */
		LSTEP = LSTEPS[STEPindex];

		while (root)
		{
			Ltemp = L_shr(interpolation_cos129(round32(Lfrequency)), 1);
			for (j = 1; j < 5; j++)
				s[j] = Ltemp;
			s[5] = L_shr(Ltemp, 1);

			for (j = 2; j < 7; j++)
			{
				t[j] = L_mpy_ll(s[j - 1], t[j - 1]);
				t[j] = L_shl(t[j], 2);
				t[j] = L_sub(t[j], t[j - 2]);
				t[j] = L_add(t[j], Lq[j - 1 + offset]);
			}

			num = (((t[6] > 0) && (Lprev[iswitch] < 0)) ||
				   ((t[6] < 0) && (Lprev[iswitch] > 0)) || (t[6] == 0));
			if ((num == 1) || (Lfrequency >= 0x40000000L))
			{

				if (STEPindex == STEPSNUM - 1)
				{

					if (L_abs(t[6]) < L_abs(Lprev[iswitch]))

						freq[lspnumber] = round32(Lfrequency);
					else
						freq[lspnumber] = round32(L_sub(Lfrequency, LSTEP));

					if ((Lprev[iswitch]) < 0)

						Lprev[iswitch] = LW_MAX;	/*was 9e9 */
					else
						Lprev[iswitch] = LW_MIN;	/*was 9e9 */

					root = FALSE;
					Lfrequency = LastFreq;
					STEPindex = 0;
				}
				else
				{

					if (STEPindex == 0)
						LastFreq = Lfrequency;
					Lfrequency =
						L_sub(Lfrequency, LSTEPS[++STEPindex]);
					/* Go back one grid step */
					LSTEP = (LSTEPS[STEPindex]);
				}
			}
			else
			{
				Lprev[iswitch] = t[6];
				Lfrequency = L_add(Lfrequency, LSTEP);

			}
		}
		lspnumber++;

		if (lspnumber > ORDER - 1)
			notlast = FALSE;
		iswitch = 1 - iswitch;
	}
}