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/*
** Copyright 2003-2010, VisualOn, Inc.
**
** Licensed under the Apache License, Version 2.0 (the "License");
** you may not use this file except in compliance with the License.
** You may obtain a copy of the License at
**
** http://www.apache.org/licenses/LICENSE-2.0
**
** Unless required by applicable law or agreed to in writing, software
** distributed under the License is distributed on an "AS IS" BASIS,
** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
** See the License for the specific language governing permissions and
** limitations under the License.
*/
/***********************************************************************
* File: weight_a.c *
* *
* Description:Weighting of LPC coefficients *
* ap[i] = a[i] * (gamma ** i) *
* *
************************************************************************/
#include "typedef.h"
#include "basic_op.h"
void Weight_a(
Word16 a[], /* (i) Q12 : a[m+1] LPC coefficients */
Word16 ap[], /* (o) Q12 : Spectral expanded LPC coefficients */
Word16 gamma, /* (i) Q15 : Spectral expansion factor. */
Word16 m /* (i) : LPC order. */
)
{
Word32 num = m - 1, fac;
*ap++ = *a++;
fac = gamma;
do{
*ap++ =(Word16)(((vo_L_mult((*a++), fac)) + 0x8000) >> 16);
fac = (vo_L_mult(fac, gamma) + 0x8000) >> 16;
}while(--num != 0);
*ap++ = (Word16)(((vo_L_mult((*a++), fac)) + 0x8000) >> 16);
return;
}
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