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: syn_filt.c                                               *
19*                                                                      *
20*       Description: Do the synthesis filtering 1/A(z)                 *
21*                                                                      *
22************************************************************************/
23
24#include "typedef.h"
25#include "basic_op.h"
26#include "math_op.h"
27#include "cnst.h"
28
29#define UNUSED(x) (void)(x)
30
31void Syn_filt(
32        Word16 a[],                           /* (i) Q12 : a[m+1] prediction coefficients           */
33        Word16 x[],                           /* (i)     : input signal                             */
34        Word16 y[],                           /* (o)     : output signal                            */
35        Word16 lg,                            /* (i)     : size of filtering                        */
36        Word16 mem[],                         /* (i/o)   : memory associated with this filtering.   */
37        Word16 update                         /* (i)     : 0=no update, 1=update of memory.         */
38         )
39{
40    Word32 i, a0;
41    Word16 y_buf[L_SUBFR16k + M16k];
42    Word32 L_tmp;
43    Word16 *yy, *p1, *p2;
44    yy = &y_buf[0];
45    /* copy initial filter states into synthesis buffer */
46    for (i = 0; i < 16; i++)
47    {
48        *yy++ = mem[i];
49    }
50    a0 = (a[0] >> 1);                     /* input / 2 */
51    /* Do the filtering. */
52    for (i = 0; i < lg; i++)
53    {
54        p1 = &a[1];
55        p2 = &yy[i-1];
56        L_tmp  = vo_mult32(a0, x[i]);
57        L_tmp -= vo_mult32((*p1++), (*p2--));
58        L_tmp -= vo_mult32((*p1++), (*p2--));
59        L_tmp -= vo_mult32((*p1++), (*p2--));
60        L_tmp -= vo_mult32((*p1++), (*p2--));
61        L_tmp -= vo_mult32((*p1++), (*p2--));
62        L_tmp -= vo_mult32((*p1++), (*p2--));
63        L_tmp -= vo_mult32((*p1++), (*p2--));
64        L_tmp -= vo_mult32((*p1++), (*p2--));
65        L_tmp -= vo_mult32((*p1++), (*p2--));
66        L_tmp -= vo_mult32((*p1++), (*p2--));
67        L_tmp -= vo_mult32((*p1++), (*p2--));
68        L_tmp -= vo_mult32((*p1++), (*p2--));
69        L_tmp -= vo_mult32((*p1++), (*p2--));
70        L_tmp -= vo_mult32((*p1++), (*p2--));
71        L_tmp -= vo_mult32((*p1++), (*p2--));
72        L_tmp -= vo_mult32((*p1), (*p2));
73
74        L_tmp = L_shl2(L_tmp, 4);
75        y[i] = yy[i] = extract_h(L_add(L_tmp, 0x8000));
76    }
77    /* Update memory if required */
78    if (update)
79        for (i = 0; i < 16; i++)
80        {
81            mem[i] = yy[lg - 16 + i];
82        }
83    return;
84}
85
86
87void Syn_filt_32(
88        Word16 a[],                           /* (i) Q12 : a[m+1] prediction coefficients */
89        Word16 m,                             /* (i)     : order of LP filter             */
90        Word16 exc[],                         /* (i) Qnew: excitation (exc[i] >> Qnew)    */
91        Word16 Qnew,                          /* (i)     : exc scaling = 0(min) to 8(max) */
92        Word16 sig_hi[],                      /* (o) /16 : synthesis high                 */
93        Word16 sig_lo[],                      /* (o) /16 : synthesis low                  */
94        Word16 lg                             /* (i)     : size of filtering              */
95        )
96{
97    Word32 i,a0;
98    Word32 L_tmp, L_tmp1;
99    Word16 *p1, *p2, *p3;
100        UNUSED(m);
101
102    a0 = a[0] >> (4 + Qnew);          /* input / 16 and >>Qnew */
103    /* Do the filtering. */
104    for (i = 0; i < lg; i++)
105    {
106        L_tmp  = 0;
107        L_tmp1 = 0;
108        p1 = a;
109        p2 = &sig_lo[i - 1];
110        p3 = &sig_hi[i - 1];
111
112        L_tmp  -= vo_mult32((*p2--), (*p1));
113        L_tmp1 -= vo_mult32((*p3--), (*p1++));
114        L_tmp  -= vo_mult32((*p2--), (*p1));
115        L_tmp1 -= vo_mult32((*p3--), (*p1++));
116        L_tmp  -= vo_mult32((*p2--), (*p1));
117        L_tmp1 -= vo_mult32((*p3--), (*p1++));
118        L_tmp  -= vo_mult32((*p2--), (*p1));
119        L_tmp1 -= vo_mult32((*p3--), (*p1++));
120        L_tmp  -= vo_mult32((*p2--), (*p1));
121        L_tmp1 -= vo_mult32((*p3--), (*p1++));
122        L_tmp  -= vo_mult32((*p2--), (*p1));
123        L_tmp1 -= vo_mult32((*p3--), (*p1++));
124        L_tmp  -= vo_mult32((*p2--), (*p1));
125        L_tmp1 -= vo_mult32((*p3--), (*p1++));
126        L_tmp  -= vo_mult32((*p2--), (*p1));
127        L_tmp1 -= vo_mult32((*p3--), (*p1++));
128        L_tmp  -= vo_mult32((*p2--), (*p1));
129        L_tmp1 -= vo_mult32((*p3--), (*p1++));
130        L_tmp  -= vo_mult32((*p2--), (*p1));
131        L_tmp1 -= vo_mult32((*p3--), (*p1++));
132        L_tmp  -= vo_mult32((*p2--), (*p1));
133        L_tmp1 -= vo_mult32((*p3--), (*p1++));
134        L_tmp  -= vo_mult32((*p2--), (*p1));
135        L_tmp1 -= vo_mult32((*p3--), (*p1++));
136        L_tmp  -= vo_mult32((*p2--), (*p1));
137        L_tmp1 -= vo_mult32((*p3--), (*p1++));
138        L_tmp  -= vo_mult32((*p2--), (*p1));
139        L_tmp1 -= vo_mult32((*p3--), (*p1++));
140        L_tmp  -= vo_mult32((*p2--), (*p1));
141        L_tmp1 -= vo_mult32((*p3--), (*p1++));
142        L_tmp  -= vo_mult32((*p2--), (*p1));
143        L_tmp1 -= vo_mult32((*p3--), (*p1++));
144
145        L_tmp = L_tmp >> 11;
146        L_tmp += vo_L_mult(exc[i], a0);
147
148        /* sig_hi = bit16 to bit31 of synthesis */
149        L_tmp = L_tmp - (L_tmp1<<1);
150
151        L_tmp = L_tmp >> 3;           /* ai in Q12 */
152        sig_hi[i] = extract_h(L_tmp);
153
154        /* sig_lo = bit4 to bit15 of synthesis */
155        L_tmp >>= 4;           /* 4 : sig_lo[i] >> 4 */
156        sig_lo[i] = (Word16)((L_tmp - (sig_hi[i] << 13)));
157    }
158
159    return;
160}
161
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165