| /* ------------------------------------------------------------------ |
| * Copyright (C) 1998-2009 PacketVideo |
| * |
| * 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. |
| * ------------------------------------------------------------------- |
| */ |
| /**************************************************************************************** |
| Portions of this file are derived from the following 3GPP standard: |
| |
| 3GPP TS 26.073 |
| ANSI-C code for the Adaptive Multi-Rate (AMR) speech codec |
| Available from http://www.3gpp.org |
| |
| (C) 2004, 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TTA, TTC) |
| Permission to distribute, modify and use this file under the standard license |
| terms listed above has been obtained from the copyright holder. |
| ****************************************************************************************/ |
| /* |
| ------------------------------------------------------------------------------ |
| |
| |
| |
| Filename: /audio/gsm-amr/c/src/a_refl.c |
| Functions: a_refl |
| |
| Date: 02/05/2002 |
| |
| ------------------------------------------------------------------------------ |
| REVISION HISTORY |
| |
| Description: Removing unneeded include files and the goto statement. |
| |
| |
| Description: Changed function name to pv_round to avoid conflict with |
| round function in C standard library. |
| |
| Description: Replaced "int" and/or "char" with OSCL defined types. |
| |
| Description: Using inline functions from basic_op.h . |
| Removing unneeded include files. |
| |
| Description: |
| |
| ------------------------------------------------------------------------------ |
| */ |
| |
| |
| /*---------------------------------------------------------------------------- |
| ; INCLUDES |
| ----------------------------------------------------------------------------*/ |
| #include "a_refl.h" |
| #include "typedef.h" |
| #include "cnst.h" |
| #include "basic_op.h" |
| |
| /*---------------------------------------------------------------------------- |
| ; MACROS [optional] |
| ; [Define module specific macros here] |
| ----------------------------------------------------------------------------*/ |
| |
| /*---------------------------------------------------------------------------- |
| ; DEFINES [optional] |
| ; [Include all pre-processor statements here. Include conditional |
| ; compile variables also.] |
| ----------------------------------------------------------------------------*/ |
| |
| /*---------------------------------------------------------------------------- |
| ; LOCAL FUNCTION DEFINITIONS |
| ; [List function prototypes here] |
| ----------------------------------------------------------------------------*/ |
| |
| /*---------------------------------------------------------------------------- |
| ; LOCAL VARIABLE DEFINITIONS |
| ; [Variable declaration - defined here and used outside this module] |
| ----------------------------------------------------------------------------*/ |
| |
| /* |
| ------------------------------------------------------------------------------ |
| FUNCTION NAME: AMREncode |
| ------------------------------------------------------------------------------ |
| INPUT AND OUTPUT DEFINITIONS |
| |
| Inputs: |
| a[] = pointer to directform coefficients of type Word16 |
| refl[] = pointer to reflection coefficients of type Word16 |
| |
| Outputs: |
| pOverflow = 1 if overflow exists in the math operations else zero. |
| |
| Returns: |
| None |
| |
| Global Variables Used: |
| None |
| |
| Local Variables Needed: |
| None |
| |
| ------------------------------------------------------------------------------ |
| FUNCTION DESCRIPTION |
| |
| File : a_refl.c |
| Purpose : Convert from direct form coefficients to |
| reflection coefficients |
| |
| ------------------------------------------------------------------------------ |
| REQUIREMENTS |
| |
| None |
| |
| ------------------------------------------------------------------------------ |
| REFERENCES |
| |
| [1] a_refl.c , 3GPP TS 26.101 version 4.1.0 Release 4, June 2001 |
| |
| ------------------------------------------------------------------------------ |
| PSEUDO-CODE |
| |
| |
| void A_Refl( |
| Word16 a[], // i : Directform coefficients |
| Word16 refl[] // o : Reflection coefficients |
| ) |
| { |
| // local variables |
| Word16 i,j; |
| Word16 aState[M]; |
| Word16 bState[M]; |
| Word16 normShift; |
| Word16 normProd; |
| Word32 L_acc; |
| Word16 scale; |
| Word32 L_temp; |
| Word16 temp; |
| Word16 mult; |
| |
| // initialize states |
| for (i = 0; i < M; i++) |
| { |
| aState[i] = a[i]; |
| } |
| |
| // backward Levinson recursion |
| for (i = M-1; i >= 0; i--) |
| { |
| if (sub(abs_s(aState[i]), 4096) >= 0) |
| { |
| goto ExitRefl; |
| } |
| |
| refl[i] = shl(aState[i], 3); |
| |
| L_temp = L_mult(refl[i], refl[i]); |
| L_acc = L_sub(MAX_32, L_temp); |
| |
| normShift = norm_l(L_acc); |
| scale = sub(15, normShift); |
| |
| L_acc = L_shl(L_acc, normShift); |
| normProd = pv_round(L_acc); |
| |
| mult = div_s(16384, normProd); |
| |
| for (j = 0; j < i; j++) |
| { |
| L_acc = L_deposit_h(aState[j]); |
| L_acc = L_msu(L_acc, refl[i], aState[i-j-1]); |
| |
| temp = pv_round(L_acc); |
| L_temp = L_mult(mult, temp); |
| L_temp = L_shr_r(L_temp, scale); |
| |
| if (L_sub(L_abs(L_temp), 32767) > 0) |
| { |
| goto ExitRefl; |
| } |
| |
| bState[j] = extract_l(L_temp); |
| } |
| |
| for (j = 0; j < i; j++) |
| { |
| aState[j] = bState[j]; |
| } |
| } |
| return; |
| |
| ExitRefl: |
| for (i = 0; i < M; i++) |
| { |
| refl[i] = 0; |
| } |
| } |
| |
| ------------------------------------------------------------------------------ |
| RESOURCES USED [optional] |
| |
| When the code is written for a specific target processor the |
| the resources used should be documented below. |
| |
| HEAP MEMORY USED: x bytes |
| |
| STACK MEMORY USED: x bytes |
| |
| CLOCK CYCLES: (cycle count equation for this function) + (variable |
| used to represent cycle count for each subroutine |
| called) |
| where: (cycle count variable) = cycle count for [subroutine |
| name] |
| |
| ------------------------------------------------------------------------------ |
| CAUTION [optional] |
| [State any special notes, constraints or cautions for users of this function] |
| |
| ------------------------------------------------------------------------------ |
| */ |
| |
| void A_Refl( |
| Word16 a[], /* i : Directform coefficients */ |
| Word16 refl[], /* o : Reflection coefficients */ |
| Flag *pOverflow |
| ) |
| { |
| /* local variables */ |
| Word16 i; |
| Word16 j; |
| Word16 aState[M]; |
| Word16 bState[M]; |
| Word16 normShift; |
| Word16 normProd; |
| Word32 L_acc; |
| Word16 scale; |
| Word32 L_temp; |
| Word16 temp; |
| Word16 mult; |
| |
| /* initialize states */ |
| for (i = 0; i < M; i++) |
| { |
| aState[i] = a[i]; |
| } |
| |
| /* backward Levinson recursion */ |
| for (i = M - 1; i >= 0; i--) |
| { |
| if (abs_s(aState[i]) >= 4096) |
| { |
| for (i = 0; i < M; i++) |
| { |
| refl[i] = 0; |
| } |
| break; |
| } |
| |
| refl[i] = shl(aState[i], 3, pOverflow); |
| |
| L_temp = L_mult(refl[i], refl[i], pOverflow); |
| L_acc = L_sub(MAX_32, L_temp, pOverflow); |
| |
| normShift = norm_l(L_acc); |
| scale = sub(15, normShift, pOverflow); |
| |
| L_acc = L_shl(L_acc, normShift, pOverflow); |
| normProd = pv_round(L_acc, pOverflow); |
| |
| mult = div_s(16384, normProd); |
| |
| for (j = 0; j < i; j++) |
| { |
| L_acc = L_deposit_h(aState[j]); |
| L_acc = L_msu(L_acc, refl[i], aState[i-j-1], pOverflow); |
| |
| temp = pv_round(L_acc, pOverflow); |
| L_temp = L_mult(mult, temp, pOverflow); |
| L_temp = L_shr_r(L_temp, scale, pOverflow); |
| |
| if (L_abs(L_temp) > 32767) |
| { |
| for (i = 0; i < M; i++) |
| { |
| refl[i] = 0; |
| } |
| break; |
| } |
| |
| bState[j] = extract_l(L_temp); |
| } |
| |
| for (j = 0; j < i; j++) |
| { |
| aState[j] = bState[j]; |
| } |
| } |
| return; |
| } |
| |
| |
| |
| |
| |
| |
| |