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 "BQ_1I_D16F16Css_TRC_WRA_01_Private.h"
20#include "LVM_Macros.h"
21
22/**************************************************************************
23 ASSUMPTIONS:
24 COEFS-
25 pBiquadState->coefs[0] is A2, pBiquadState->coefs[1] is A1
26 pBiquadState->coefs[2] is A0, pBiquadState->coefs[3] is -B2
27 pBiquadState->coefs[4] is -B1, these are in Q15 format
28
29 DELAYS-
30 pBiquadState->pDelays[0] is x(n-1)L in Q0 format
31 pBiquadState->pDelays[1] is x(n-2)L in Q0 format
32 pBiquadState->pDelays[2] is y(n-1)L in Q0 format
33 pBiquadState->pDelays[3] is y(n-2)L in Q0 format
34***************************************************************************/
35
36void BQ_1I_D16F16C15_TRC_WRA_01 ( Biquad_Instance_t       *pInstance,
37                                  LVM_INT16               *pDataIn,
38                                  LVM_INT16               *pDataOut,
39                                  LVM_INT16               NrSamples)
40    {
41        LVM_INT32  ynL;
42        LVM_INT16 ii;
43        PFilter_State pBiquadState = (PFilter_State) pInstance;
44
45         for (ii = NrSamples; ii != 0; ii--)
46         {
47
48
49            /**************************************************************************
50                            PROCESSING OF THE LEFT CHANNEL
51            ***************************************************************************/
52            // ynL=A2 (Q15) * x(n-2)L (Q0) in Q15
53            ynL=(LVM_INT32)pBiquadState->coefs[0]* pBiquadState->pDelays[1];
54
55            // ynL+=A1 (Q15) * x(n-1)L (Q0) in Q15
56            ynL+=(LVM_INT32)pBiquadState->coefs[1]* pBiquadState->pDelays[0];
57
58            // ynL+=A0 (Q15) * x(n)L (Q0) in Q15
59            ynL+=(LVM_INT32)pBiquadState->coefs[2]* (*pDataIn);
60
61            // ynL+=  (-B2 (Q15) * y(n-2)L (Q0) ) in Q15
62            ynL+=(LVM_INT32)pBiquadState->coefs[3]*pBiquadState->pDelays[3];
63
64            // ynL+= (-B1 (Q15) * y(n-1)L (Q0) ) in Q15
65            ynL+=(LVM_INT32)pBiquadState->coefs[4]*pBiquadState->pDelays[2];
66
67            ynL=ynL>>15; // ynL in Q0 format
68            /**************************************************************************
69                            UPDATING THE DELAYS
70            ***************************************************************************/
71            pBiquadState->pDelays[3]=pBiquadState->pDelays[2]; // y(n-2)L=y(n-1)L
72            pBiquadState->pDelays[1]=pBiquadState->pDelays[0]; // x(n-2)L=x(n-1)L
73            pBiquadState->pDelays[2]=ynL; // Update y(n-1)L in Q0
74            pBiquadState->pDelays[0]=(*pDataIn++); // Update x(n-1)L in Q0
75
76            /**************************************************************************
77                            WRITING THE OUTPUT
78            ***************************************************************************/
79            *pDataOut++=(LVM_INT16)ynL; // Write Left output in Q0
80
81
82        }
83
84    }
85
86