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 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
