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_2I_D16F16Css_TRC_WRA_01_Private.h"
20#include "LVM_Macros.h"
21
22
23/**************************************************************************
24 ASSUMPTIONS:
25 COEFS-
26 pBiquadState->coefs[0] is A2, pBiquadState->coefs[1] is A1
27 pBiquadState->coefs[2] is A0, pBiquadState->coefs[3] is -B2
28 pBiquadState->coefs[4] is -B1, these are in Q15 format
29
30 DELAYS-
31 pBiquadState->pDelays[0] is x(n-1)L in Q0 format
32 pBiquadState->pDelays[1] is x(n-1)R in Q0 format
33 pBiquadState->pDelays[2] is x(n-2)L in Q0 format
34 pBiquadState->pDelays[3] is x(n-2)R in Q0 format
35 pBiquadState->pDelays[4] is y(n-1)L in Q0 format
36 pBiquadState->pDelays[5] is y(n-1)R in Q0 format
37 pBiquadState->pDelays[6] is y(n-2)L in Q0 format
38 pBiquadState->pDelays[7] is y(n-2)R in Q0 format
39***************************************************************************/
40
41void BQ_2I_D16F16C15_TRC_WRA_01 ( Biquad_Instance_t       *pInstance,
42                                  LVM_INT16               *pDataIn,
43                                  LVM_INT16               *pDataOut,
44                                  LVM_INT16               NrSamples)
45    {
46        LVM_INT32  ynL,ynR;
47        LVM_INT16 ii;
48        PFilter_State pBiquadState = (PFilter_State) pInstance;
49
50         for (ii = NrSamples; ii != 0; ii--)
51         {
52
53
54            /**************************************************************************
55                            PROCESSING OF THE LEFT CHANNEL
56            ***************************************************************************/
57            // ynL=A2 (Q15) * x(n-2)L (Q0) in Q15
58            ynL=(LVM_INT32)pBiquadState->coefs[0]* pBiquadState->pDelays[2];
59
60            // ynL+=A1 (Q15) * x(n-1)L (Q0) in Q15
61            ynL+=(LVM_INT32)pBiquadState->coefs[1]* pBiquadState->pDelays[0];
62
63            // ynL+=A0 (Q15) * x(n)L (Q0) in Q15
64            ynL+=(LVM_INT32)pBiquadState->coefs[2]* (*pDataIn);
65
66            // ynL+= ( -B2 (Q15) * y(n-2)L (Q0) ) in Q15
67            ynL+=(LVM_INT32)pBiquadState->coefs[3]*pBiquadState->pDelays[6];
68
69            // ynL+=( -B1 (Q15) * y(n-1)L (Q0) ) in Q15
70            ynL+=(LVM_INT32)pBiquadState->coefs[4]*pBiquadState->pDelays[4];
71
72            ynL=ynL>>15; // ynL in Q0 format
73
74            /**************************************************************************
75                            PROCESSING OF THE RIGHT CHANNEL
76            ***************************************************************************/
77            // ynR=A2 (Q15) * x(n-2)R (Q0) in Q15
78            ynR=(LVM_INT32)pBiquadState->coefs[0]*pBiquadState->pDelays[3];
79
80            // ynR+=A1 (Q15) * x(n-1)R (Q0) in Q15
81            ynR+=(LVM_INT32)pBiquadState->coefs[1]*pBiquadState->pDelays[1];
82
83            // ynR+=A0 (Q15) * x(n)R (Q0) in Q15
84            ynR+=(LVM_INT32)pBiquadState->coefs[2]*(*(pDataIn+1));
85
86            // ynR+= ( -B2 (Q15) * y(n-2)R (Q0) ) in Q15
87            ynR+=(LVM_INT32)pBiquadState->coefs[3]*pBiquadState->pDelays[7];
88
89            // ynR+=( -B1 (Q15) * y(n-1)R (Q0) ) in Q15
90            ynR+=(LVM_INT32)pBiquadState->coefs[4]*pBiquadState->pDelays[5];
91
92            ynR=ynR>>15; // ynL in Q0 format
93            /**************************************************************************
94                            UPDATING THE DELAYS
95            ***************************************************************************/
96            pBiquadState->pDelays[7]=pBiquadState->pDelays[5];  // y(n-2)R=y(n-1)R
97            pBiquadState->pDelays[6]=pBiquadState->pDelays[4];  // y(n-2)L=y(n-1)L
98            pBiquadState->pDelays[3]=pBiquadState->pDelays[1];  // x(n-2)R=x(n-1)R
99            pBiquadState->pDelays[2]=pBiquadState->pDelays[0];  // x(n-2)L=x(n-1)L
100            pBiquadState->pDelays[5]=ynR;                       // Update y(n-1)R in Q0
101            pBiquadState->pDelays[4]=ynL;                       // Update y(n-1)L in Q0
102            pBiquadState->pDelays[0]=(*pDataIn++);              // Update x(n-1)L in Q0
103            pBiquadState->pDelays[1]=(*pDataIn++);              // Update x(n-1)R in Q0
104
105            /**************************************************************************
106                            WRITING THE OUTPUT
107            ***************************************************************************/
108            *pDataOut++=(LVM_INT16)ynL; // Write Left output in Q0
109            *pDataOut++=(LVM_INT16)ynR; // Write Right ouput in Q0
110
111        }
112
113    }
114
115