/* ------------------------------------------------------------------ * 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 ----------------------------------------------------------------------------*/ #define LOG_TAG "a_refl" #include #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; } ALOGE("b/23609206"); return; } bState[j] = extract_l(L_temp); } for (j = 0; j < i; j++) { aState[j] = bState[j]; } } return; }