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 "FO_1I_D16F16Css_TRC_WRA_01_Private.h"
20#include "LVM_Macros.h"
21
22/**************************************************************************
23 ASSUMPTIONS:
24 COEFS-
25 pBiquadState->coefs[0] is A1,
26 pBiquadState->coefs[1] is A0,
27 pBiquadState->coefs[2] 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 y(n-1)L in Q0 format
32***************************************************************************/
33
34void FO_1I_D16F16C15_TRC_WRA_01( Biquad_Instance_t       *pInstance,
35                                 LVM_INT16               *pDataIn,
36                                 LVM_INT16               *pDataOut,
37                                 LVM_INT16               NrSamples)
38    {
39        LVM_INT32  ynL;
40        LVM_INT16 ii;
41        PFilter_State pBiquadState = (PFilter_State) pInstance;
42
43         for (ii = NrSamples; ii != 0; ii--)
44         {
45
46            /**************************************************************************
47                            PROCESSING OF THE LEFT CHANNEL
48            ***************************************************************************/
49            // ynL=A1 (Q15) * x(n-1)L (Q0) in Q15
50            ynL=(LVM_INT32)pBiquadState->coefs[0]* pBiquadState->pDelays[0];
51
52            // ynL+=A0 (Q15) * x(n)L (Q0) in Q15
53            ynL+=(LVM_INT32)pBiquadState->coefs[1]* (*pDataIn);
54
55            // ynL+=  (-B1 (Q15) * y(n-1)L (Q0) ) in Q15
56            ynL+=(LVM_INT32)pBiquadState->coefs[2]*pBiquadState->pDelays[1];
57
58
59            ynL=(LVM_INT16)(ynL>>15); // ynL in Q0 format
60            /**************************************************************************
61                            UPDATING THE DELAYS
62            ***************************************************************************/
63            pBiquadState->pDelays[1]=ynL; // Update y(n-1)L in Q0
64            pBiquadState->pDelays[0]=(*pDataIn++); // Update x(n-1)L in Q0
65
66            /**************************************************************************
67                            WRITING THE OUTPUT
68            ***************************************************************************/
69            *pDataOut++=(LVM_INT16)ynL; // Write Left output in Q0
70
71        }
72
73    }
74
75