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
BQ_1I_D16F16C15_TRC_WRA_01(Biquad_Instance_t * pInstance,LVM_INT16 * pDataIn,LVM_INT16 * pDataOut,LVM_INT16 NrSamples)36 void 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