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 ***************************************************************************/
BQ_1I_D16F16C15_TRC_WRA_01(Biquad_FLOAT_Instance_t * pInstance,LVM_FLOAT * pDataIn,LVM_FLOAT * pDataOut,LVM_INT16 NrSamples)35 void BQ_1I_D16F16C15_TRC_WRA_01 ( Biquad_FLOAT_Instance_t *pInstance,
36 LVM_FLOAT *pDataIn,
37 LVM_FLOAT *pDataOut,
38 LVM_INT16 NrSamples)
39 {
40 LVM_FLOAT ynL;
41 LVM_INT16 ii;
42 PFilter_State_FLOAT pBiquadState = (PFilter_State_FLOAT) pInstance;
43
44 for (ii = NrSamples; ii != 0; ii--)
45 {
46
47 /**************************************************************************
48 PROCESSING OF THE LEFT CHANNEL
49 ***************************************************************************/
50 // ynL=A2 * x(n-2)L
51 ynL = (LVM_FLOAT)pBiquadState->coefs[0] * pBiquadState->pDelays[1];
52
53 // ynL+=A1 * x(n-1)L
54 ynL += (LVM_FLOAT)pBiquadState->coefs[1] * pBiquadState->pDelays[0];
55
56 // ynL+=A0 * x(n)L
57 ynL += (LVM_FLOAT)pBiquadState->coefs[2] * (*pDataIn);
58
59 // ynL+= (-B2 * y(n-2)L )
60 ynL += (LVM_FLOAT)pBiquadState->coefs[3] * pBiquadState->pDelays[3];
61
62 // ynL+= (-B1 * y(n-1)L )
63 ynL += (LVM_FLOAT)pBiquadState->coefs[4] * pBiquadState->pDelays[2];
64
65 /**************************************************************************
66 UPDATING THE DELAYS
67 ***************************************************************************/
68 pBiquadState->pDelays[3] = pBiquadState->pDelays[2]; // y(n-2)L=y(n-1)L
69 pBiquadState->pDelays[1] = pBiquadState->pDelays[0]; // x(n-2)L=x(n-1)L
70 pBiquadState->pDelays[2] = ynL; // Update y(n-1)L
71 pBiquadState->pDelays[0] = (*pDataIn++); // Update x(n-1)L
72
73 /**************************************************************************
74 WRITING THE OUTPUT
75 ***************************************************************************/
76 *pDataOut++ = (LVM_FLOAT)ynL; // Write Left output in Q0
77
78 }
79
80 }
81