mirror of https://github.com/mstorsjo/fdk-aac.git
259 lines
8.9 KiB
C
259 lines
8.9 KiB
C
/* -----------------------------------------------------------------------------
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Software License for The Fraunhofer FDK AAC Codec Library for Android
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© Copyright 1995 - 2018 Fraunhofer-Gesellschaft zur Förderung der angewandten
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Forschung e.V. All rights reserved.
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1. INTRODUCTION
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The Fraunhofer FDK AAC Codec Library for Android ("FDK AAC Codec") is software
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that implements the MPEG Advanced Audio Coding ("AAC") encoding and decoding
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scheme for digital audio. This FDK AAC Codec software is intended to be used on
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a wide variety of Android devices.
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AAC's HE-AAC and HE-AAC v2 versions are regarded as today's most efficient
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general perceptual audio codecs. AAC-ELD is considered the best-performing
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full-bandwidth communications codec by independent studies and is widely
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deployed. AAC has been standardized by ISO and IEC as part of the MPEG
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specifications.
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Patent licenses for necessary patent claims for the FDK AAC Codec (including
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those of Fraunhofer) may be obtained through Via Licensing
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(www.vialicensing.com) or through the respective patent owners individually for
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the purpose of encoding or decoding bit streams in products that are compliant
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with the ISO/IEC MPEG audio standards. Please note that most manufacturers of
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Android devices already license these patent claims through Via Licensing or
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directly from the patent owners, and therefore FDK AAC Codec software may
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already be covered under those patent licenses when it is used for those
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licensed purposes only.
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Commercially-licensed AAC software libraries, including floating-point versions
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with enhanced sound quality, are also available from Fraunhofer. Users are
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encouraged to check the Fraunhofer website for additional applications
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information and documentation.
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2. COPYRIGHT LICENSE
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Redistribution and use in source and binary forms, with or without modification,
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are permitted without payment of copyright license fees provided that you
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satisfy the following conditions:
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You must retain the complete text of this software license in redistributions of
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the FDK AAC Codec or your modifications thereto in source code form.
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You must retain the complete text of this software license in the documentation
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and/or other materials provided with redistributions of the FDK AAC Codec or
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your modifications thereto in binary form. You must make available free of
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charge copies of the complete source code of the FDK AAC Codec and your
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modifications thereto to recipients of copies in binary form.
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The name of Fraunhofer may not be used to endorse or promote products derived
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from this library without prior written permission.
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You may not charge copyright license fees for anyone to use, copy or distribute
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the FDK AAC Codec software or your modifications thereto.
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Your modified versions of the FDK AAC Codec must carry prominent notices stating
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that you changed the software and the date of any change. For modified versions
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of the FDK AAC Codec, the term "Fraunhofer FDK AAC Codec Library for Android"
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must be replaced by the term "Third-Party Modified Version of the Fraunhofer FDK
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AAC Codec Library for Android."
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3. NO PATENT LICENSE
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NO EXPRESS OR IMPLIED LICENSES TO ANY PATENT CLAIMS, including without
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limitation the patents of Fraunhofer, ARE GRANTED BY THIS SOFTWARE LICENSE.
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Fraunhofer provides no warranty of patent non-infringement with respect to this
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software.
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You may use this FDK AAC Codec software or modifications thereto only for
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purposes that are authorized by appropriate patent licenses.
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4. DISCLAIMER
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This FDK AAC Codec software is provided by Fraunhofer on behalf of the copyright
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holders and contributors "AS IS" and WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES,
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including but not limited to the implied warranties of merchantability and
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fitness for a particular purpose. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
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CONTRIBUTORS BE LIABLE for any direct, indirect, incidental, special, exemplary,
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or consequential damages, including but not limited to procurement of substitute
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goods or services; loss of use, data, or profits, or business interruption,
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however caused and on any theory of liability, whether in contract, strict
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liability, or tort (including negligence), arising in any way out of the use of
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this software, even if advised of the possibility of such damage.
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5. CONTACT INFORMATION
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Fraunhofer Institute for Integrated Circuits IIS
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Attention: Audio and Multimedia Departments - FDK AAC LL
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Am Wolfsmantel 33
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91058 Erlangen, Germany
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www.iis.fraunhofer.de/amm
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amm-info@iis.fraunhofer.de
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----------------------------------------------------------------------------- */
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/******************* Library for basic calculation routines ********************
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Author(s): Haricharan Lakshman, Manuel Jander
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Description: Trigonometric functions fixed point fractional implementation.
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*******************************************************************************/
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#if !defined(FDK_TRIGFCTS_H)
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#define FDK_TRIGFCTS_H
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#include "common_fix.h"
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#include "FDK_tools_rom.h"
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/* Fixed point precision definitions */
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#define Q(format) ((FIXP_DBL)(((LONG)1) << (format)))
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#ifndef M_PI
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#define M_PI (3.14159265358979323846f)
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#endif
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/*!
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* Inverse tangent function.
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*/
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/* --- fixp_atan() ---- */
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#define Q_ATANINP (25) // Input in q25, Output in q30
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#define Q_ATANOUT (30)
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#define ATI_SF ((DFRACT_BITS - 1) - Q_ATANINP) /* 6 */
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#define ATI_SCALE ((float)(1 << ATI_SF))
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#define ATO_SF ((DFRACT_BITS - 1) - Q_ATANOUT) /* 1 ] -pi/2 .. pi/2 [ */
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#define ATO_SCALE ((float)(1 << ATO_SF))
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/* --- fixp_atan2() --- */
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#define Q_ATAN2OUT (29)
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#define AT2O_SF ((DFRACT_BITS - 1) - Q_ATAN2OUT) /* 2 ] -pi .. pi ] */
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#define AT2O_SCALE ((float)(1 << AT2O_SF))
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// --------------------
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FIXP_DBL fixp_atan(FIXP_DBL x);
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FIXP_DBL fixp_atan2(FIXP_DBL y, FIXP_DBL x);
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FIXP_DBL fixp_cos(FIXP_DBL x, int scale);
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FIXP_DBL fixp_sin(FIXP_DBL x, int scale);
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#define FIXP_COS_SIN
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#include "FDK_tools_rom.h"
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#define SINETAB SineTable512
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#define LD 9
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#ifndef FUNCTION_inline_fixp_cos_sin
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#define FUNCTION_inline_fixp_cos_sin
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/*
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* Calculates coarse lookup index and sign for sine.
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* Returns delta x residual.
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*/
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static inline FIXP_DBL fixp_sin_cos_residual_inline(FIXP_DBL x, int scale,
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FIXP_DBL *sine,
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FIXP_DBL *cosine) {
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FIXP_DBL residual;
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int s;
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int shift = (31 - scale - LD - 1);
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int ssign = 1;
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int csign = 1;
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residual = fMult(x, FL2FXCONST_DBL(1.0 / M_PI));
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s = ((LONG)residual) >> shift;
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residual &= ((1 << shift) - 1);
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residual = fMult(residual, FL2FXCONST_DBL(M_PI / 4.0)) << 2;
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residual <<= scale;
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/* Sine sign symmetry */
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if (s & ((1 << LD) << 1)) {
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ssign = -ssign;
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}
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/* Cosine sign symmetry */
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if ((s + (1 << LD)) & ((1 << LD) << 1)) {
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csign = -csign;
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}
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s = fAbs(s);
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s &= (((1 << LD) << 1) - 1); /* Modulo PI */
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if (s > (1 << LD)) {
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s = ((1 << LD) << 1) - s;
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}
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{
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LONG sl, cl;
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/* Because of packed table */
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if (s > (1 << (LD - 1))) {
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FIXP_STP tmp;
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/* Cosine/Sine simetry for angles greater than PI/4 */
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s = (1 << LD) - s;
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tmp = SINETAB[s];
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sl = (LONG)tmp.v.re;
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cl = (LONG)tmp.v.im;
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} else {
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FIXP_STP tmp;
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tmp = SINETAB[s];
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sl = (LONG)tmp.v.im;
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cl = (LONG)tmp.v.re;
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}
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#ifdef SINETABLE_16BIT
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*sine = (FIXP_DBL)((sl * ssign) << (DFRACT_BITS - FRACT_BITS));
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*cosine = (FIXP_DBL)((cl * csign) << (DFRACT_BITS - FRACT_BITS));
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#else
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/* scale down by 1 for overflow prevention. This is undone at the calling
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* function. */
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*sine = (FIXP_DBL)(sl * ssign) >> 1;
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*cosine = (FIXP_DBL)(cl * csign) >> 1;
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#endif
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}
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return residual;
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}
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/**
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* \brief Calculate cosine and sine value each of 2 angles different angle
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* values.
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* \param x1 first angle value
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* \param x2 second angle value
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* \param scale exponent of x1 and x2
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* \param out pointer to 4 FIXP_DBL locations, were the values cos(x1), sin(x1),
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* cos(x2), sin(x2) will be stored into.
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*/
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static inline void inline_fixp_cos_sin(FIXP_DBL x1, FIXP_DBL x2,
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const int scale, FIXP_DBL *out) {
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FIXP_DBL residual, error0, error1, sine, cosine;
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residual = fixp_sin_cos_residual_inline(x1, scale, &sine, &cosine);
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error0 = fMultDiv2(sine, residual);
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error1 = fMultDiv2(cosine, residual);
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#ifdef SINETABLE_16BIT
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*out++ = cosine - (error0 << 1);
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*out++ = sine + (error1 << 1);
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#else
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/* Undo downscaling by 1 which was done at fixp_sin_cos_residual_inline */
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*out++ = SATURATE_LEFT_SHIFT(cosine - (error0 << 1), 1, DFRACT_BITS);
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*out++ = SATURATE_LEFT_SHIFT(sine + (error1 << 1), 1, DFRACT_BITS);
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#endif
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residual = fixp_sin_cos_residual_inline(x2, scale, &sine, &cosine);
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error0 = fMultDiv2(sine, residual);
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error1 = fMultDiv2(cosine, residual);
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#ifdef SINETABLE_16BIT
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*out++ = cosine - (error0 << 1);
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*out++ = sine + (error1 << 1);
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#else
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*out++ = SATURATE_LEFT_SHIFT(cosine - (error0 << 1), 1, DFRACT_BITS);
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*out++ = SATURATE_LEFT_SHIFT(sine + (error1 << 1), 1, DFRACT_BITS);
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#endif
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}
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#endif
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#endif /* !defined(FDK_TRIGFCTS_H) */
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