| /* |
| * Copyright (C) 2004-2010 NXP Software |
| * Copyright (C) 2010 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #include "BIQUAD.h" |
| #include "FO_2I_D16F32Css_LShx_TRC_WRA_01_Private.h" |
| #include "LVM_Macros.h" |
| |
| /************************************************************************** |
| ASSUMPTIONS: |
| COEFS- |
| pBiquadState->coefs[0] is A1, |
| pBiquadState->coefs[1] is A0, |
| pBiquadState->coefs[2] is -B1, these are in Q15 format |
| pBiquadState->Shift is Shift value |
| DELAYS- |
| pBiquadState->pDelays[0] is x(n-1)L in Q15 format |
| pBiquadState->pDelays[1] is y(n-1)L in Q30 format |
| pBiquadState->pDelays[2] is x(n-1)R in Q15 format |
| pBiquadState->pDelays[3] is y(n-1)R in Q30 format |
| ***************************************************************************/ |
| |
| void FO_2I_D16F32C15_LShx_TRC_WRA_01(Biquad_Instance_t *pInstance, |
| LVM_INT16 *pDataIn, |
| LVM_INT16 *pDataOut, |
| LVM_INT16 NrSamples) |
| { |
| LVM_INT32 ynL,ynR; |
| LVM_INT32 Temp; |
| LVM_INT32 NegSatValue; |
| LVM_INT16 ii; |
| LVM_INT16 Shift; |
| PFilter_State pBiquadState = (PFilter_State) pInstance; |
| |
| NegSatValue = LVM_MAXINT_16 +1; |
| NegSatValue = -NegSatValue; |
| |
| Shift = pBiquadState->Shift; |
| |
| |
| for (ii = NrSamples; ii != 0; ii--) |
| { |
| |
| /************************************************************************** |
| PROCESSING OF THE LEFT CHANNEL |
| ***************************************************************************/ |
| |
| // ynL =A1 (Q15) * x(n-1)L (Q15) in Q30 |
| ynL=(LVM_INT32)pBiquadState->coefs[0]* pBiquadState->pDelays[0]; |
| // ynR =A1 (Q15) * x(n-1)R (Q15) in Q30 |
| ynR=(LVM_INT32)pBiquadState->coefs[0]* pBiquadState->pDelays[2]; |
| |
| |
| // ynL+=A0 (Q15) * x(n)L (Q15) in Q30 |
| ynL+=(LVM_INT32)pBiquadState->coefs[1]* (*pDataIn); |
| // ynR+=A0 (Q15) * x(n)L (Q15) in Q30 |
| ynR+=(LVM_INT32)pBiquadState->coefs[1]* (*(pDataIn+1)); |
| |
| |
| // ynL += (-B1 (Q15) * y(n-1)L (Q30) ) in Q30 |
| MUL32x16INTO32(pBiquadState->pDelays[1],pBiquadState->coefs[2],Temp,15); |
| ynL +=Temp; |
| // ynR += (-B1 (Q15) * y(n-1)R (Q30) ) in Q30 |
| MUL32x16INTO32(pBiquadState->pDelays[3],pBiquadState->coefs[2],Temp,15); |
| ynR +=Temp; |
| |
| |
| /************************************************************************** |
| UPDATING THE DELAYS |
| ***************************************************************************/ |
| pBiquadState->pDelays[1]=ynL; // Update y(n-1)L in Q30 |
| pBiquadState->pDelays[0]=(*pDataIn++); // Update x(n-1)L in Q15 |
| |
| pBiquadState->pDelays[3]=ynR; // Update y(n-1)R in Q30 |
| pBiquadState->pDelays[2]=(*pDataIn++); // Update x(n-1)R in Q15 |
| |
| /************************************************************************** |
| WRITING THE OUTPUT |
| ***************************************************************************/ |
| /*Apply shift: Instead of left shift on 16-bit result, right shift of (15-shift) is applied |
| for better SNR*/ |
| ynL = ynL>>(15-Shift); |
| ynR = ynR>>(15-Shift); |
| |
| /*Saturate results*/ |
| if(ynL > LVM_MAXINT_16) |
| { |
| ynL = LVM_MAXINT_16; |
| } |
| else |
| { |
| if(ynL < NegSatValue) |
| { |
| ynL = NegSatValue; |
| } |
| } |
| |
| if(ynR > LVM_MAXINT_16) |
| { |
| ynR = LVM_MAXINT_16; |
| } |
| else |
| { |
| if(ynR < NegSatValue) |
| { |
| ynR = NegSatValue; |
| } |
| } |
| |
| *pDataOut++=(LVM_INT16)ynL; |
| *pDataOut++=(LVM_INT16)ynR; |
| } |
| |
| } |
| |