1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
|
/*
** 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: autocorr.c *
* *
* Description:Compute autocorrelations of signal with windowing *
* *
************************************************************************/
#include "typedef.h"
#include "basic_op.h"
#include "oper_32b.h"
#include "acelp.h"
#include "ham_wind.tab"
#define UNUSED(x) (void)(x)
void Autocorr(
Word16 x[], /* (i) : Input signal */
Word16 m, /* (i) : LPC order */
Word16 r_h[], /* (o) Q15: Autocorrelations (msb) */
Word16 r_l[] /* (o) : Autocorrelations (lsb) */
)
{
Word32 i, norm, shift;
Word16 y[L_WINDOW];
Word32 L_sum, L_sum1, L_tmp, F_LEN;
Word16 *p1,*p2,*p3;
const Word16 *p4;
UNUSED(m);
/* Windowing of signal */
p1 = x;
p4 = vo_window;
p3 = y;
for (i = 0; i < L_WINDOW; i+=4)
{
*p3++ = vo_mult_r((*p1++), (*p4++));
*p3++ = vo_mult_r((*p1++), (*p4++));
*p3++ = vo_mult_r((*p1++), (*p4++));
*p3++ = vo_mult_r((*p1++), (*p4++));
}
/* calculate energy of signal */
L_sum = vo_L_deposit_h(16); /* sqrt(256), avoid overflow after rounding */
for (i = 0; i < L_WINDOW; i++)
{
L_tmp = vo_L_mult(y[i], y[i]);
L_tmp = (L_tmp >> 8);
L_sum += L_tmp;
}
/* scale signal to avoid overflow in autocorrelation */
norm = norm_l(L_sum);
shift = 4 - (norm >> 1);
if(shift > 0)
{
p1 = y;
for (i = 0; i < L_WINDOW; i+=4)
{
*p1 = vo_shr_r(*p1, shift);
p1++;
*p1 = vo_shr_r(*p1, shift);
p1++;
*p1 = vo_shr_r(*p1, shift);
p1++;
*p1 = vo_shr_r(*p1, shift);
p1++;
}
}
/* Compute and normalize r[0] */
L_sum = 1;
for (i = 0; i < L_WINDOW; i+=4)
{
L_sum += vo_L_mult(y[i], y[i]);
L_sum += vo_L_mult(y[i+1], y[i+1]);
L_sum += vo_L_mult(y[i+2], y[i+2]);
L_sum += vo_L_mult(y[i+3], y[i+3]);
}
norm = norm_l(L_sum);
L_sum = (L_sum << norm);
r_h[0] = L_sum >> 16;
r_l[0] = (L_sum & 0xffff)>>1;
/* Compute r[1] to r[m] */
for (i = 1; i <= 8; i++)
{
L_sum1 = 0;
L_sum = 0;
F_LEN = (Word32)(L_WINDOW - 2*i);
p1 = y;
p2 = y + (2*i)-1;
do{
L_sum1 += *p1 * *p2++;
L_sum += *p1++ * *p2;
}while(--F_LEN!=0);
L_sum1 += *p1 * *p2++;
L_sum1 = L_sum1<<norm;
L_sum = L_sum<<norm;
r_h[(2*i)-1] = L_sum1 >> 15;
r_l[(2*i)-1] = L_sum1 & 0x00007fff;
r_h[(2*i)] = L_sum >> 15;
r_l[(2*i)] = L_sum & 0x00007fff;
}
return;
}
|
