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 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
