/* | |
** 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; | |
} | |