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 Q14 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_D16F16C14_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 PROCESSING OF THE LEFT CHANNEL 55 ***************************************************************************/ 56 // ynL=A2 (Q14) * x(n-2)L (Q0) in Q14 57 ynL=(LVM_INT32)pBiquadState->coefs[0]* pBiquadState->pDelays[2]; 58 59 // ynL+=A1 (Q14) * x(n-1)L (Q0) in Q14 60 ynL+=(LVM_INT32)pBiquadState->coefs[1]* pBiquadState->pDelays[0]; 61 62 // ynL+=A0 (Q14) * x(n)L (Q0) in Q14 63 ynL+=(LVM_INT32)pBiquadState->coefs[2]* (*pDataIn); 64 65 // ynL+= ( -B2 (Q14) * y(n-2)L (Q0) ) in Q14 66 ynL+=(LVM_INT32)pBiquadState->coefs[3]*pBiquadState->pDelays[6]; 67 68 // ynL+=( -B1 (Q14) * y(n-1)L (Q0) ) in Q14 69 ynL+=(LVM_INT32)pBiquadState->coefs[4]*pBiquadState->pDelays[4]; 70 71 ynL=ynL>>14; // ynL in Q0 format 72 73 /************************************************************************** 74 PROCESSING OF THE RIGHT CHANNEL 75 ***************************************************************************/ 76 // ynR=A2 (Q14) * x(n-2)R (Q0) in Q14 77 ynR=(LVM_INT32)pBiquadState->coefs[0]*pBiquadState->pDelays[3]; 78 79 // ynR+=A1 (Q14) * x(n-1)R (Q0) in Q14 80 ynR+=(LVM_INT32)pBiquadState->coefs[1]*pBiquadState->pDelays[1]; 81 82 // ynR+=A0 (Q14) * x(n)R (Q0) in Q14 83 ynR+=(LVM_INT32)pBiquadState->coefs[2]*(*(pDataIn+1)); 84 85 // ynR+= ( -B2 (Q14) * y(n-2)R (Q0) ) in Q14 86 ynR+=(LVM_INT32)pBiquadState->coefs[3]*pBiquadState->pDelays[7]; 87 88 // ynR+=( -B1 (Q14) * y(n-1)R (Q0) ) in Q14 89 ynR+=(LVM_INT32)pBiquadState->coefs[4]*pBiquadState->pDelays[5]; 90 91 ynR=ynR>>14; // ynL in Q0 format 92 /************************************************************************** 93 UPDATING THE DELAYS 94 ***************************************************************************/ 95 pBiquadState->pDelays[7]=pBiquadState->pDelays[5]; // y(n-2)R=y(n-1)R 96 pBiquadState->pDelays[6]=pBiquadState->pDelays[4]; // y(n-2)L=y(n-1)L 97 pBiquadState->pDelays[3]=pBiquadState->pDelays[1]; // x(n-2)R=x(n-1)R 98 pBiquadState->pDelays[2]=pBiquadState->pDelays[0]; // x(n-2)L=x(n-1)L 99 pBiquadState->pDelays[5]=ynR; // Update y(n-1)R in Q0 100 pBiquadState->pDelays[4]=ynL; // Update y(n-1)L in Q0 101 pBiquadState->pDelays[0]=(*pDataIn++); // Update x(n-1)L in Q0 102 pBiquadState->pDelays[1]=(*pDataIn++); // Update x(n-1)R in Q0 103 104 /************************************************************************** 105 WRITING THE OUTPUT 106 ***************************************************************************/ 107 *pDataOut++=(LVM_INT16)ynL; // Write Left output in Q0 108 *pDataOut++=(LVM_INT16)ynR; // Write Right ouput in Q0 109 110 111 } 112 113 } 114 115
