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
BQ_2I_D16F16C15_TRC_WRA_01(Biquad_Instance_t * pInstance,LVM_INT16 * pDataIn,LVM_INT16 * pDataOut,LVM_INT16 NrSamples)41 void 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