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Diffstat (limited to 'libSBRdec/src/transcendent.h')
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diff --git a/libSBRdec/src/transcendent.h b/libSBRdec/src/transcendent.h new file mode 100644 index 0000000..fae36d6 --- /dev/null +++ b/libSBRdec/src/transcendent.h @@ -0,0 +1,313 @@ +/**************************************************************************** + + (C) Copyright Fraunhofer IIS (2004) + All Rights Reserved + + Please be advised that this software and/or program delivery is + Confidential Information of Fraunhofer and subject to and covered by the + + Fraunhofer IIS Software Evaluation Agreement + between Google Inc. and Fraunhofer + effective and in full force since March 1, 2012. + + You may use this software and/or program only under the terms and + conditions described in the above mentioned Fraunhofer IIS Software + Evaluation Agreement. Any other and/or further use requires a separate agreement. + + + This software and/or program is protected by copyright law and international + treaties. Any reproduction or distribution of this software and/or program, + or any portion of it, may result in severe civil and criminal penalties, and + will be prosecuted to the maximum extent possible under law. + + $Id$ + +*******************************************************************************/ +/*! + \file + \brief FDK Fixed Point Arithmetic Library Interface $Revision: 36841 $ +*/ + +/*! + \mainpage Fixed Point Arithmetic Library Documentation + + Information in this SDK is subject to change without notice. Companies, + names, and data used in examples herein are fictitious unless otherwise + noted. + + Product and corporate names may be trademarks or registered trademarks + of other companies. They are used for explanation only, with no intent + to infringe. + + No part of this publication may be reproduced or utilized in any form or + by any means, electronic or mechanical, including photocopying and + microfilm, without permission in writing from the publisher. +*/ + +#ifndef __TRANSCENDENT_H +#define __TRANSCENDENT_H + +#include "sbrdecoder.h" +#include "sbr_rom.h" + +/************************************************************************/ +/*! + \brief Get number of octaves between frequencies a and b + + The Result is scaled with 1/8. + The valid range for a and b is 1 to LOG_DUALIS_TABLE_SIZE. + + \return ld(a/b) / 8 +*/ +/************************************************************************/ +static inline FIXP_SGL FDK_getNumOctavesDiv8(INT a, /*!< lower band */ + INT b) /*!< upper band */ +{ + return ( (SHORT)((LONG)(CalcLdInt(b) - CalcLdInt(a))>>(FRACT_BITS-3)) ); +} + + +/************************************************************************/ +/*! + \brief Add two values given by mantissa and exponent. + + Mantissas are in fract format with values between 0 and 1. <br> + The base for exponents is 2. Example: \f$ a = a\_m * 2^{a\_e} \f$<br> +*/ +/************************************************************************/ +inline void FDK_add_MantExp(FIXP_SGL a_m, /*!< Mantissa of 1st operand a */ + SCHAR a_e, /*!< Exponent of 1st operand a */ + FIXP_SGL b_m, /*!< Mantissa of 2nd operand b */ + SCHAR b_e, /*!< Exponent of 2nd operand b */ + FIXP_SGL *ptrSum_m, /*!< Mantissa of result */ + SCHAR *ptrSum_e) /*!< Exponent of result */ +{ + FIXP_DBL accu; + int shift; + int shiftAbs; + + FIXP_DBL shiftedMantissa; + FIXP_DBL otherMantissa; + + /* Equalize exponents of the summands. + For the smaller summand, the exponent is adapted and + for compensation, the mantissa is shifted right. */ + + shift = (int)(a_e - b_e); + + shiftAbs = (shift>0)? shift : -shift; + shiftAbs = (shiftAbs < DFRACT_BITS-1)? shiftAbs : DFRACT_BITS-1; + shiftedMantissa = (shift>0)? (FX_SGL2FX_DBL(b_m) >> shiftAbs) : (FX_SGL2FX_DBL(a_m) >> shiftAbs); + otherMantissa = (shift>0)? FX_SGL2FX_DBL(a_m) : FX_SGL2FX_DBL(b_m); + *ptrSum_e = (shift>0)? a_e : b_e; + + accu = (shiftedMantissa >> 1) + (otherMantissa >> 1); + /* shift by 1 bit to avoid overflow */ + + if ( (accu >= (FL2FXCONST_DBL(0.5f) - (FIXP_DBL)1)) || (accu <= FL2FXCONST_DBL(-0.5f)) ) + *ptrSum_e += 1; + else + accu = (shiftedMantissa + otherMantissa); + + *ptrSum_m = FX_DBL2FX_SGL(accu); + +} + +inline void FDK_add_MantExp(FIXP_DBL a, /*!< Mantissa of 1st operand a */ + SCHAR a_e, /*!< Exponent of 1st operand a */ + FIXP_DBL b, /*!< Mantissa of 2nd operand b */ + SCHAR b_e, /*!< Exponent of 2nd operand b */ + FIXP_DBL *ptrSum, /*!< Mantissa of result */ + SCHAR *ptrSum_e) /*!< Exponent of result */ +{ + FIXP_DBL accu; + int shift; + int shiftAbs; + + FIXP_DBL shiftedMantissa; + FIXP_DBL otherMantissa; + + /* Equalize exponents of the summands. + For the smaller summand, the exponent is adapted and + for compensation, the mantissa is shifted right. */ + + shift = (int)(a_e - b_e); + + shiftAbs = (shift>0)? shift : -shift; + shiftAbs = (shiftAbs < DFRACT_BITS-1)? shiftAbs : DFRACT_BITS-1; + shiftedMantissa = (shift>0)? (b >> shiftAbs) : (a >> shiftAbs); + otherMantissa = (shift>0)? a : b; + *ptrSum_e = (shift>0)? a_e : b_e; + + accu = (shiftedMantissa >> 1) + (otherMantissa >> 1); + /* shift by 1 bit to avoid overflow */ + + if ( (accu >= (FL2FXCONST_DBL(0.5f) - (FIXP_DBL)1)) || (accu <= FL2FXCONST_DBL(-0.5f)) ) + *ptrSum_e += 1; + else + accu = (shiftedMantissa + otherMantissa); + + *ptrSum = accu; + +} + +/************************************************************************/ +/*! + \brief Divide two values given by mantissa and exponent. + + Mantissas are in fract format with values between 0 and 1. <br> + The base for exponents is 2. Example: \f$ a = a\_m * 2^{a\_e} \f$<br> + + For performance reasons, the division is based on a table lookup + which limits accuracy. +*/ +/************************************************************************/ +static inline void FDK_divide_MantExp(FIXP_SGL a_m, /*!< Mantissa of dividend a */ + SCHAR a_e, /*!< Exponent of dividend a */ + FIXP_SGL b_m, /*!< Mantissa of divisor b */ + SCHAR b_e, /*!< Exponent of divisor b */ + FIXP_SGL *ptrResult_m, /*!< Mantissa of quotient a/b */ + SCHAR *ptrResult_e) /*!< Exponent of quotient a/b */ + +{ + int preShift, postShift, index, shift; + FIXP_DBL ratio_m; + FIXP_SGL bInv_m = FL2FXCONST_SGL(0.0f); + + preShift = CntLeadingZeros(FX_SGL2FX_DBL(b_m)); + + /* + Shift b into the range from 0..INV_TABLE_SIZE-1, + + E.g. 10 bits must be skipped for INV_TABLE_BITS 8: + - leave 8 bits as index for table + - skip sign bit, + - skip first bit of mantissa, because this is always the same (>0.5) + + We are dealing with energies, so we need not care + about negative numbers + */ + + /* + The first interval has half width so the lowest bit of the index is + needed for a doubled resolution. + */ + shift = (FRACT_BITS - 2 - INV_TABLE_BITS - preShift); + + index = (shift<0)? (LONG)b_m << (-shift) : (LONG)b_m >> shift; + + + /* The index has INV_TABLE_BITS +1 valid bits here. Clear the other bits. */ + index &= (1 << (INV_TABLE_BITS+1)) - 1; + + /* Remove offset of half an interval */ + index--; + + /* Now the lowest bit is shifted out */ + index = index >> 1; + + /* Fetch inversed mantissa from table: */ + bInv_m = (index<0)? bInv_m : FDK_sbrDecoder_invTable[index]; + + /* Multiply a with the inverse of b: */ + ratio_m = (index<0)? FX_SGL2FX_DBL(a_m >> 1) : fMultDiv2(bInv_m,a_m); + + postShift = CntLeadingZeros(ratio_m)-1; + + *ptrResult_m = FX_DBL2FX_SGL(ratio_m << postShift); + *ptrResult_e = a_e - b_e + 1 + preShift - postShift; +} + +static inline void FDK_divide_MantExp(FIXP_DBL a_m, /*!< Mantissa of dividend a */ + SCHAR a_e, /*!< Exponent of dividend a */ + FIXP_DBL b_m, /*!< Mantissa of divisor b */ + SCHAR b_e, /*!< Exponent of divisor b */ + FIXP_DBL *ptrResult_m, /*!< Mantissa of quotient a/b */ + SCHAR *ptrResult_e) /*!< Exponent of quotient a/b */ + +{ + int preShift, postShift, index, shift; + FIXP_DBL ratio_m; + FIXP_SGL bInv_m = FL2FXCONST_SGL(0.0f); + + preShift = CntLeadingZeros(b_m); + + /* + Shift b into the range from 0..INV_TABLE_SIZE-1, + + E.g. 10 bits must be skipped for INV_TABLE_BITS 8: + - leave 8 bits as index for table + - skip sign bit, + - skip first bit of mantissa, because this is always the same (>0.5) + + We are dealing with energies, so we need not care + about negative numbers + */ + + /* + The first interval has half width so the lowest bit of the index is + needed for a doubled resolution. + */ + shift = (DFRACT_BITS - 2 - INV_TABLE_BITS - preShift); + + index = (shift<0)? (LONG)b_m << (-shift) : (LONG)b_m >> shift; + + + /* The index has INV_TABLE_BITS +1 valid bits here. Clear the other bits. */ + index &= (1 << (INV_TABLE_BITS+1)) - 1; + + /* Remove offset of half an interval */ + index--; + + /* Now the lowest bit is shifted out */ + index = index >> 1; + + /* Fetch inversed mantissa from table: */ + bInv_m = (index<0)? bInv_m : FDK_sbrDecoder_invTable[index]; + + /* Multiply a with the inverse of b: */ + ratio_m = (index<0)? (a_m >> 1) : fMultDiv2(bInv_m,a_m); + + postShift = CntLeadingZeros(ratio_m)-1; + + *ptrResult_m = ratio_m << postShift; + *ptrResult_e = a_e - b_e + 1 + preShift - postShift; +} + +/*! + \brief Calculate the squareroot of a number given by mantissa and exponent + + Mantissa is in fract format with values between 0 and 1. <br> + The base for the exponent is 2. Example: \f$ a = a\_m * 2^{a\_e} \f$<br> + The operand is addressed via pointers and will be overwritten with the result. + + For performance reasons, the square root is based on a table lookup + which limits accuracy. +*/ +static inline void FDK_sqrt_MantExp(FIXP_DBL *mantissa, /*!< Pointer to mantissa */ + SCHAR *exponent, + const SCHAR *destScale) +{ + FIXP_DBL input_m = *mantissa; + int input_e = (int) *exponent; + FIXP_DBL result = FL2FXCONST_DBL(0.0f); + int result_e = -FRACT_BITS; + + /* Call lookup square root, which does internally normalization. */ + result = sqrtFixp_lookup(input_m, &input_e); + result_e = input_e; + + /* Write result */ + if (exponent==destScale) { + *mantissa = result; + *exponent = result_e; + } else { + int shift = result_e - *destScale; + *mantissa = (shift>=0) ? result << (INT)fixMin(DFRACT_BITS-1,shift) + : result >> (INT)fixMin(DFRACT_BITS-1,-shift); + *exponent = *destScale; + } +} + + +#endif |