1 /*
2 ** Copyright 2003-2010, VisualOn, Inc.
3 **
4 ** Licensed under the Apache License, Version 2.0 (the "License");
5 ** you may not use this file except in compliance with the License.
6 ** You may obtain a copy of the License at
7 **
8 ** http://www.apache.org/licenses/LICENSE-2.0
9 **
10 ** Unless required by applicable law or agreed to in writing, software
11 ** distributed under the License is distributed on an "AS IS" BASIS,
12 ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 ** See the License for the specific language governing permissions and
14 ** limitations under the License.
15 */
16
17 /***********************************************************************
18 * File: cor_h_x.c *
19 * *
20 * Description:Compute correlation between target "x[]" and "h[]" *
21 * Designed for codebook search (24 pulses, 4 tracks, *
22 * 4 pulses per track, 16 positions in each track) to *
23 * avoid saturation. *
24 * *
25 ************************************************************************/
26
27 #include "typedef.h"
28 #include "basic_op.h"
29 #include "math_op.h"
30
31 #define L_SUBFR 64
32 #define NB_TRACK 4
33 #define STEP 4
34
cor_h_x(Word16 h[],Word16 x[],Word16 dn[])35 void cor_h_x(
36 Word16 h[], /* (i) Q12 : impulse response of weighted synthesis filter */
37 Word16 x[], /* (i) Q0 : target vector */
38 Word16 dn[] /* (o) <12bit : correlation between target and h[] */
39 )
40 {
41 Word32 i, j;
42 Word32 L_tmp, y32[L_SUBFR], L_tot;
43 Word16 *p1, *p2;
44 Word32 *p3;
45 Word32 L_max, L_max1, L_max2, L_max3;
46 /* first keep the result on 32 bits and find absolute maximum */
47 L_tot = 1;
48 L_max = 0;
49 L_max1 = 0;
50 L_max2 = 0;
51 L_max3 = 0;
52 for (i = 0; i < L_SUBFR; i += STEP)
53 {
54 L_tmp = 1; /* 1 -> to avoid null dn[] */
55 p1 = &x[i];
56 p2 = &h[0];
57 for (j = i; j < L_SUBFR; j++)
58 L_tmp = L_add(L_tmp, vo_L_mult(*p1++, *p2++));
59
60 y32[i] = L_tmp;
61 L_tmp = (L_tmp > 0)? L_tmp: (L_tmp == INT_MIN ? INT_MAX : -L_tmp);
62 if(L_tmp > L_max)
63 {
64 L_max = L_tmp;
65 }
66
67 L_tmp = 1L;
68 p1 = &x[i+1];
69 p2 = &h[0];
70 for (j = i+1; j < L_SUBFR; j++)
71 L_tmp = L_add(L_tmp, vo_L_mult(*p1++, *p2++));
72
73 y32[i+1] = L_tmp;
74 L_tmp = (L_tmp > 0)? L_tmp: (L_tmp == INT_MIN ? INT_MAX : -L_tmp);
75 if(L_tmp > L_max1)
76 {
77 L_max1 = L_tmp;
78 }
79
80 L_tmp = 1;
81 p1 = &x[i+2];
82 p2 = &h[0];
83 for (j = i+2; j < L_SUBFR; j++)
84 L_tmp = L_add(L_tmp, vo_L_mult(*p1++, *p2++));
85
86 y32[i+2] = L_tmp;
87 L_tmp = (L_tmp > 0)? L_tmp: (L_tmp == INT_MIN ? INT_MAX : -L_tmp);
88 if(L_tmp > L_max2)
89 {
90 L_max2 = L_tmp;
91 }
92
93 L_tmp = 1;
94 p1 = &x[i+3];
95 p2 = &h[0];
96 for (j = i+3; j < L_SUBFR; j++)
97 L_tmp = L_add(L_tmp, vo_L_mult(*p1++, *p2++));
98
99 y32[i+3] = L_tmp;
100 L_tmp = (L_tmp > 0)? L_tmp: (L_tmp == INT_MIN ? INT_MAX : -L_tmp);
101 if(L_tmp > L_max3)
102 {
103 L_max3 = L_tmp;
104 }
105 }
106 /* tot += 3*max / 8 */
107 if (L_max > INT_MAX - L_max1 ||
108 L_max + L_max1 > INT_MAX - L_max2 ||
109 L_max + L_max1 + L_max2 > INT_MAX - L_max3) {
110 L_max = INT_MAX >> 2;
111 } else {
112 L_max = ((L_max + L_max1 + L_max2 + L_max3) >> 2);
113 }
114 L_tot = vo_L_add(L_tot, L_max); /* +max/4 */
115 L_tot = vo_L_add(L_tot, (L_max >> 1)); /* +max/8 */
116
117 /* Find the number of right shifts to do on y32[] so that */
118 /* 6.0 x sumation of max of dn[] in each track not saturate. */
119 j = norm_l(L_tot) - 4; /* 4 -> 16 x tot */
120 p1 = dn;
121 p3 = y32;
122 for (i = 0; i < L_SUBFR; i+=4)
123 {
124 *p1++ = vo_round(L_shl(*p3++, j));
125 *p1++ = vo_round(L_shl(*p3++, j));
126 *p1++ = vo_round(L_shl(*p3++, j));
127 *p1++ = vo_round(L_shl(*p3++, j));
128 }
129 return;
130 }
131
132
133
134