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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: residu.c *
* *
* Description: Compute the LPC residual by filtering *
* the input speech through A(z) *
* *
************************************************************************/
#include "typedef.h"
#include "basic_op.h"
void Residu(
Word16 a[], /* (i) Q12 : prediction coefficients */
Word16 x[], /* (i) : speech (values x[-m..-1] are needed */
Word16 y[], /* (o) x2 : residual signal */
Word16 lg /* (i) : size of filtering */
)
{
Word16 i,*p1, *p2;
Word32 s;
for (i = 0; i < lg; i++)
{
p1 = a;
p2 = &x[i];
s = vo_mult32((*p1++), (*p2--));
s += vo_mult32((*p1++), (*p2--));
s += vo_mult32((*p1++), (*p2--));
s += vo_mult32((*p1++), (*p2--));
s += vo_mult32((*p1++), (*p2--));
s += vo_mult32((*p1++), (*p2--));
s += vo_mult32((*p1++), (*p2--));
s += vo_mult32((*p1++), (*p2--));
s += vo_mult32((*p1++), (*p2--));
s += vo_mult32((*p1++), (*p2--));
s += vo_mult32((*p1++), (*p2--));
s += vo_mult32((*p1++), (*p2--));
s += vo_mult32((*p1++), (*p2--));
s += vo_mult32((*p1++), (*p2--));
s += vo_mult32((*p1++), (*p2--));
s += vo_mult32((*p1++), (*p2--));
s += vo_mult32((*p1), (*p2));
s = L_shl2(s, 5);
y[i] = extract_h(L_add(s, 0x8000));
}
return;
}
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