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      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 /*-------------------------------------------------------------------------*/
     19 #include "BIQUAD.h"
     20 #include "BP_1I_D16F32Cll_TRC_WRA_01_Private.h"
     21 
     22 
     23 /*-------------------------------------------------------------------------*/
     24 /* FUNCTION:                                                               */
     25 /*   BP_1I_D16F32Cll_TRC_WRA_01_Init                                       */
     26 /*                                                                         */
     27 /* DESCRIPTION:                                                            */
     28 /*   These functions initializes a Band pass filter (BIQUAD)               */
     29 /*   biquadratic Filter Sections.                                          */
     30 /*                                                                         */
     31 /* PARAMETERS:                                                             */
     32 /*   pInstance    - output, returns the pointer to the State Variable      */
     33 /*                   This state pointer must be passed to any subsequent   */
     34 /*                   call to "Biquad" functions.                           */
     35 /*   pTaps         - input, pointer to the taps memory                     */
     36 /*   pCoef         - input, pointer to the coefficient structure           */
     37 /*   N             - M coefficient factor of QM.N                          */
     38 /*                                                                         */
     39 /*        The coefficients are modified in the init() function such that lower               */
     40 /*        half word is right shifted by one and most significant bit of the lower            */
     41 /*        word is made to be zero.                                                           */
     42 /*                                                                                           */
     43 /*       Reason: For MIPS effciency,we are using DSP 32*16 multiplication                    */
     44 /*       instruction. But we have 32*32 multiplication. This can be realized by two 32*16    */
     45 /*       multiplication. But 16th bit in the 32 bit word is not a sign bit. So this is done  */
     46 /*       by putting 16th bit to zero and lossing one bit precision by division of lower      */
     47 /*       half word by 2.                                                                     */
     48 /* RETURNS:                                                                */
     49 /*   void return code                                                      */
     50 /*-------------------------------------------------------------------------*/
     51 void BP_1I_D16F32Cll_TRC_WRA_01_Init (   Biquad_Instance_t         *pInstance,
     52                                          Biquad_1I_Order2_Taps_t   *pTaps,
     53                                          BP_C32_Coefs_t            *pCoef)
     54 {
     55   PFilter_State pBiquadState = (PFilter_State) pInstance;
     56   pBiquadState->pDelays       =(LVM_INT32 *) pTaps;
     57 
     58   pBiquadState->coefs[0] =  pCoef->A0;
     59   pBiquadState->coefs[1] =  pCoef->B2;
     60   pBiquadState->coefs[2] =  pCoef->B1;
     61 }
     62 /*-------------------------------------------------------------------------*/
     63 /* End Of File: BP_1I_D16F32Cll_TRC_WRA_01_Init.c                              */
     64 
     65