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 "BP_1I_D16F16Css_TRC_WRA_01_Private.h"
20 #include "LVM_Macros.h"
21
22
23 /**************************************************************************
24 ASSUMPTIONS:
25 COEFS-
26 pBiquadState->coefs[0] is A0,
27 pBiquadState->coefs[1] is -B2,
28 pBiquadState->coefs[2] is -B1, these are in Q14 format
29
30 DELAYS-
31 pBiquadState->pDelays[0] is x(n-1)L in Q0 format
32 pBiquadState->pDelays[1] is x(n-2)L in Q0 format
33 pBiquadState->pDelays[2] is y(n-1)L in Q0 format
34 pBiquadState->pDelays[3] is y(n-2)L in Q0 format
35 ***************************************************************************/
36
BP_1I_D16F16C14_TRC_WRA_01(Biquad_Instance_t * pInstance,LVM_INT16 * pDataIn,LVM_INT16 * pDataOut,LVM_INT16 NrSamples)37 void BP_1I_D16F16C14_TRC_WRA_01 ( Biquad_Instance_t *pInstance,
38 LVM_INT16 *pDataIn,
39 LVM_INT16 *pDataOut,
40 LVM_INT16 NrSamples)
41
42
43 {
44 LVM_INT32 ynL;
45 LVM_INT16 ii;
46 PFilter_State pBiquadState = (PFilter_State) pInstance;
47
48 for (ii = NrSamples; ii != 0; ii--)
49 {
50
51
52 /**************************************************************************
53 PROCESSING OF THE LEFT CHANNEL
54 ***************************************************************************/
55 // ynL= (A0 (Q14) * (x(n)L (Q0) - x(n-2)L (Q0) ) ) in Q14
56 ynL=(LVM_INT32)pBiquadState->coefs[0]* ((*pDataIn)-pBiquadState->pDelays[1]);
57
58 // ynL+= ((-B2 (Q14) * y(n-2)L (Q0) ) ) in Q14
59 ynL+=(LVM_INT32)pBiquadState->coefs[1]*pBiquadState->pDelays[3];
60
61 // ynL+= ((-B1 (Q30) * y(n-1)L (Q0) ) ) in Q14
62 ynL+=(LVM_INT32)pBiquadState->coefs[2]*pBiquadState->pDelays[2];
63
64 ynL=(LVM_INT16)(ynL>>14); // ynL in Q0
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 in Q0
71 pBiquadState->pDelays[0]=(*pDataIn++); // Update x(n-1)L in Q0
72
73 /**************************************************************************
74 WRITING THE OUTPUT
75 ***************************************************************************/
76 *pDataOut++=(LVM_INT16)ynL; // Write Left output in Q0
77
78 }
79
80 }
81
82