RTL271_1/evrcc/code/lsp2a.c

/**********************************************************************
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rights consistent with 3GPP2's and each Organizational Partner's  policies 
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even though this Publication may contain the Contribution or a derivative 
work thereof.  The Contribution shall disclose any known limitations on 
the Source's rights to license as herein provided.

When a Contribution is submitted by the Source(s) to assist the 
formulating groups of 3GPP2 or any of its Organizational Partners, it 
is proposed to the Committee as a basis for discussion and is not to 
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specifically reserve(s) the right to amend or modify the material 
contained in the Contribution. Nothing contained in the Contribution 
shall, except as herein expressly provided, be construed as conferring 
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With respect to the Software necessary for the practice of any or 
all Normative portions of the Enhanced Variable Rate Codec (EVRC) as 
it exists on the date of submittal of this form, should the EVRC be 
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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:                0                                           */
/*      Static/Global RAM:  0                                           */
/*      Stack/Local RAM:    51                                          */
/*----------------------------------------------------------------------*/
/************************************************************************
* Routine name: lsptopc.                                                *
* Function: Convert lsp to pc.                                          *
* Inputs: freq - Quantized line spectral frequencies.                   *
* Outputs: pc - prediction coefficients.                                *
************************************************************************/
#include "macro.h"
//#include "mathevrc.h"
#include "dsp_math.h"
#include "mathdp31.h"
#include "mathadv.h"

extern INT32 interpolation_cos129(INT16);

void lsp2a(
			  INT16 *pc,
			  INT16 *freq
)
{
	INT16 p[ORDER / 2], q[ORDER / 2];
	INT32 La[ORDER / 2 + 1], La1[ORDER / 2 + 1], La2[ORDER / 2 + 1];
	INT32 Lb[ORDER / 2 + 1], Lb1[ORDER / 2 + 1], Lb2[ORDER / 2 + 1];
	INT32 xx, xf;
	INT16 i, k;
	INT16 lspflag;

	lspflag = 1;
	/*  *** check input for ill-conditioned cases */
	if ((freq[0] <= 0) || (freq[ORDER - 1] >= 0x4000))
	{
		lspflag = 0;
		if (freq[0] <= 0)
			freq[0] = 721;		/* 0.022=720.896 */
		if (freq[ORDER - 1] >= 0x4000)
			freq[ORDER - 1] = 16351;	/*0.499 */
	}

	if (!lspflag)
	{
		xx = L_mult(sub(freq[ORDER - 1], freq[0]), 3277);
		for (i = 1; i < ORDER; i++)
			freq[i] = add(freq[i - 1], round32(xx));
	}

	for (i = 0; i <= (ORDER / 2); i++)
	{
		La[i] = 0;
		La1[i] = 0;
		La2[i] = 0;
		Lb[i] = 0;
		Lb1[i] = 0;
		Lb2[i] = 0;
	}

	for (i = 0; i < (ORDER / 2); i++)
	{
		p[i] = round32(interpolation_cos129(freq[2 * i]));
		q[i] = round32(interpolation_cos129(freq[2 * i + 1]));
	}

	xf = 0;
	xx = 0x20000000L;

	for (k = 0; k <= ORDER; k++)
	{
		La[0] = L_shr(L_add(xx, xf), 4);
		Lb[0] = L_shr(L_sub(xx, xf), 4);
		xf = xx;
		xx = 0;

		for (i = 0; i < (ORDER / 2); i++)
		{
			La[i + 1] = L_add(L_sub(La[i], L_mpy_ls(
													   L_shl(La1[i], 1), p[i])), La2[i]);
			Lb[i + 1] = L_add(L_shl(L_sub(L_shr(Lb[i], 1),
										  L_mpy_ls(Lb1[i], q[i])), 1), Lb2[i]);

			La2[i] = La1[i];
			La1[i] = La[i];
			Lb2[i] = Lb1[i];
			Lb1[i] = Lb[i];
		}

		if (k != 0)
			pc[k - 1] = round32(L_shl(L_add(La[ORDER / 2], Lb[ORDER / 2]), 2));
	}
}