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 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-1)R in Q0 format
32 pBiquadState->pDelays[2] is x(n-2)L in Q0 format
33 pBiquadState->pDelays[3] is x(n-2)R in Q0 format
34 pBiquadState->pDelays[4] is y(n-1)L in Q0 format
35 pBiquadState->pDelays[5] is y(n-1)R in Q0 format
36 pBiquadState->pDelays[6] is y(n-2)L in Q0 format
37 pBiquadState->pDelays[7] is y(n-2)R in Q0 format
38 ***************************************************************************/
BQ_2I_D16F16C15_TRC_WRA_01(Biquad_FLOAT_Instance_t * pInstance,LVM_FLOAT * pDataIn,LVM_FLOAT * pDataOut,LVM_INT16 NrSamples)39 void BQ_2I_D16F16C15_TRC_WRA_01 ( Biquad_FLOAT_Instance_t *pInstance,
40 LVM_FLOAT *pDataIn,
41 LVM_FLOAT *pDataOut,
42 LVM_INT16 NrSamples)
43 {
44 LVM_FLOAT ynL,ynR;
45 LVM_INT16 ii;
46 PFilter_State_FLOAT pBiquadState = (PFilter_State_FLOAT) pInstance;
47
48 for (ii = NrSamples; ii != 0; ii--)
49 {
50
51 /**************************************************************************
52 PROCESSING OF THE LEFT CHANNEL
53 ***************************************************************************/
54 // ynL=A2 * x(n-2)L
55 ynL = (LVM_FLOAT)pBiquadState->coefs[0] * pBiquadState->pDelays[2];
56
57 // ynL+=A1 * x(n-1)L
58 ynL += (LVM_FLOAT)pBiquadState->coefs[1] * pBiquadState->pDelays[0];
59
60 // ynL+=A0 * x(n)L
61 ynL += (LVM_FLOAT)pBiquadState->coefs[2] * (*pDataIn);
62
63 // ynL+= ( -B2 * y(n-2)L
64 ynL += (LVM_FLOAT)pBiquadState->coefs[3] * pBiquadState->pDelays[6];
65
66 // ynL+=( -B1 * y(n-1)L
67 ynL += (LVM_FLOAT)pBiquadState->coefs[4] * pBiquadState->pDelays[4];
68
69 /**************************************************************************
70 PROCESSING OF THE RIGHT CHANNEL
71 ***************************************************************************/
72 // ynR=A2 * x(n-2)R
73 ynR = (LVM_FLOAT)pBiquadState->coefs[0] * pBiquadState->pDelays[3];
74
75 // ynR+=A1 * x(n-1)R
76 ynR += (LVM_FLOAT)pBiquadState->coefs[1] * pBiquadState->pDelays[1];
77
78 // ynR+=A0 * x(n)R
79 ynR += (LVM_FLOAT)pBiquadState->coefs[2] * (*(pDataIn+1));
80
81 // ynR+= ( -B2 * y(n-2)R )
82 ynR += (LVM_FLOAT)pBiquadState->coefs[3] * pBiquadState->pDelays[7];
83
84 // ynR+=( -B1 * y(n-1)R )
85 ynR += (LVM_FLOAT)pBiquadState->coefs[4] * pBiquadState->pDelays[5];
86
87 /**************************************************************************
88 UPDATING THE DELAYS
89 ***************************************************************************/
90 pBiquadState->pDelays[7] = pBiquadState->pDelays[5]; // y(n-2)R=y(n-1)R
91 pBiquadState->pDelays[6] = pBiquadState->pDelays[4]; // y(n-2)L=y(n-1)L
92 pBiquadState->pDelays[3] = pBiquadState->pDelays[1]; // x(n-2)R=x(n-1)R
93 pBiquadState->pDelays[2] = pBiquadState->pDelays[0]; // x(n-2)L=x(n-1)L
94 pBiquadState->pDelays[5] = ynR; // Update y(n-1)R
95 pBiquadState->pDelays[4] = ynL; // Update y(n-1)L
96 pBiquadState->pDelays[0] = (*pDataIn++); // Update x(n-1)L
97 pBiquadState->pDelays[1] = (*pDataIn++); // Update x(n-1)R
98
99 /**************************************************************************
100 WRITING THE OUTPUT
101 ***************************************************************************/
102 *pDataOut++ = (LVM_FLOAT)ynL; // Write Left output
103 *pDataOut++ = (LVM_FLOAT)ynR; // Write Right ouput
104
105 }
106
107 }
108