1/*
2 * Copyright (C) 2004-2010 NXP Software
3 * Copyright (C) 2010 The Android Open Source Project
4 *
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at
8 *
9 *      http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18#include "BIQUAD.h"
19#include "BP_1I_D16F16Css_TRC_WRA_01_Private.h"
20#include "LVM_Macros.h"
21
22
23/**************************************************************************
24 ASSUMPTIONS:
25 COEFS-
26 pBiquadState->coefs[0] is A0,
27 pBiquadState->coefs[1] is -B2,
28 pBiquadState->coefs[2] is -B1, these are in Q14 format
29
30 DELAYS-
31 pBiquadState->pDelays[0] is x(n-1)L in Q0 format
32 pBiquadState->pDelays[1] is x(n-2)L in Q0 format
33 pBiquadState->pDelays[2] is y(n-1)L in Q0 format
34 pBiquadState->pDelays[3] is y(n-2)L in Q0 format
35***************************************************************************/
36
37void BP_1I_D16F16C14_TRC_WRA_01 ( Biquad_Instance_t       *pInstance,
38                                  LVM_INT16               *pDataIn,
39                                  LVM_INT16               *pDataOut,
40                                  LVM_INT16               NrSamples)
41
42
43    {
44        LVM_INT32 ynL;
45        LVM_INT16 ii;
46        PFilter_State pBiquadState = (PFilter_State) pInstance;
47
48         for (ii = NrSamples; ii != 0; ii--)
49         {
50
51
52            /**************************************************************************
53                            PROCESSING OF THE LEFT CHANNEL
54            ***************************************************************************/
55            // ynL= (A0 (Q14) * (x(n)L (Q0) - x(n-2)L (Q0) ) )  in Q14
56            ynL=(LVM_INT32)pBiquadState->coefs[0]* ((*pDataIn)-pBiquadState->pDelays[1]);
57
58            // ynL+= ((-B2 (Q14) * y(n-2)L (Q0) ) ) in Q14
59            ynL+=(LVM_INT32)pBiquadState->coefs[1]*pBiquadState->pDelays[3];
60
61            // ynL+= ((-B1 (Q30) * y(n-1)L (Q0) ) ) in Q14
62            ynL+=(LVM_INT32)pBiquadState->coefs[2]*pBiquadState->pDelays[2];
63
64            ynL=(LVM_INT16)(ynL>>14); // ynL in Q0
65            /**************************************************************************
66                            UPDATING THE DELAYS
67            ***************************************************************************/
68            pBiquadState->pDelays[3]=pBiquadState->pDelays[2]; // y(n-2)L=y(n-1)L
69            pBiquadState->pDelays[1]=pBiquadState->pDelays[0]; // x(n-2)L=x(n-1)L
70            pBiquadState->pDelays[2]=ynL; // Update y(n-1)L in Q0
71            pBiquadState->pDelays[0]=(*pDataIn++); // Update x(n-1)L in Q0
72
73            /**************************************************************************
74                            WRITING THE OUTPUT
75            ***************************************************************************/
76            *pDataOut++=(LVM_INT16)ynL; // Write Left output in Q0
77
78        }
79
80    }
81
82