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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: cor_h_x.c *
* *
* Description:Compute correlation between target "x[]" and "h[]" *
* Designed for codebook search (24 pulses, 4 tracks, *
* 4 pulses per track, 16 positions in each track) to *
* avoid saturation. *
* *
************************************************************************/
#include "typedef.h"
#include "basic_op.h"
#include "math_op.h"
#define L_SUBFR 64
#define NB_TRACK 4
#define STEP 4
void cor_h_x(
Word16 h[], /* (i) Q12 : impulse response of weighted synthesis filter */
Word16 x[], /* (i) Q0 : target vector */
Word16 dn[] /* (o) <12bit : correlation between target and h[] */
)
{
Word32 i, j;
Word32 L_tmp, y32[L_SUBFR], L_tot;
Word16 *p1, *p2;
Word32 *p3;
Word32 L_max, L_max1, L_max2, L_max3;
/* first keep the result on 32 bits and find absolute maximum */
L_tot = 1;
L_max = 0;
L_max1 = 0;
L_max2 = 0;
L_max3 = 0;
for (i = 0; i < L_SUBFR; i += STEP)
{
L_tmp = 1; /* 1 -> to avoid null dn[] */
p1 = &x[i];
p2 = &h[0];
for (j = i; j < L_SUBFR; j++)
L_tmp += vo_L_mult(*p1++, *p2++);
y32[i] = L_tmp;
L_tmp = (L_tmp > 0)? L_tmp:-L_tmp;
if(L_tmp > L_max)
{
L_max = L_tmp;
}
L_tmp = 1L;
p1 = &x[i+1];
p2 = &h[0];
for (j = i+1; j < L_SUBFR; j++)
L_tmp += vo_L_mult(*p1++, *p2++);
y32[i+1] = L_tmp;
L_tmp = (L_tmp > 0)? L_tmp:-L_tmp;
if(L_tmp > L_max1)
{
L_max1 = L_tmp;
}
L_tmp = 1;
p1 = &x[i+2];
p2 = &h[0];
for (j = i+2; j < L_SUBFR; j++)
L_tmp += vo_L_mult(*p1++, *p2++);
y32[i+2] = L_tmp;
L_tmp = (L_tmp > 0)? L_tmp:-L_tmp;
if(L_tmp > L_max2)
{
L_max2 = L_tmp;
}
L_tmp = 1;
p1 = &x[i+3];
p2 = &h[0];
for (j = i+3; j < L_SUBFR; j++)
L_tmp += vo_L_mult(*p1++, *p2++);
y32[i+3] = L_tmp;
L_tmp = (L_tmp > 0)? L_tmp:-L_tmp;
if(L_tmp > L_max3)
{
L_max3 = L_tmp;
}
}
/* tot += 3*max / 8 */
L_max = ((L_max + L_max1 + L_max2 + L_max3) >> 2);
L_tot = vo_L_add(L_tot, L_max); /* +max/4 */
L_tot = vo_L_add(L_tot, (L_max >> 1)); /* +max/8 */
/* Find the number of right shifts to do on y32[] so that */
/* 6.0 x sumation of max of dn[] in each track not saturate. */
j = norm_l(L_tot) - 4; /* 4 -> 16 x tot */
p1 = dn;
p3 = y32;
for (i = 0; i < L_SUBFR; i+=4)
{
*p1++ = vo_round(L_shl(*p3++, j));
*p1++ = vo_round(L_shl(*p3++, j));
*p1++ = vo_round(L_shl(*p3++, j));
*p1++ = vo_round(L_shl(*p3++, j));
}
return;
}
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