131 lines
3.7 KiB
C
131 lines
3.7 KiB
C
/*
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* Project 25 IMBE Encoder/Decoder Fixed-Point implementation
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* Developed by Pavel Yazev E-mail: pyazev@gmail.com
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* Version 1.0 (c) Copyright 2009
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*
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* This is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 3, or (at your option)
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* any later version.
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*
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* The software is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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* See the GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this; see the file COPYING. If not, write to the Free
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* Software Foundation, Inc., 51 Franklin Street, Boston, MA
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* 02110-1301, USA.
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*/
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#ifndef _MATH_SUB
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#define _MATH_SUB
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#define X05_Q15 16384 // (0.5*(1<<15))
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#define ONE_Q15 32767 // ((1<<15)-1)
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//-----------------------------------------------------------------------------
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// PURPOSE:
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// Computes the cosine of x whose value is expressed in radians/PI.
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//
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// INPUT:
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// x - argument in Q1.15
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//
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// OUTPUT:
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// None
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//
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// RETURN:
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// Result in Q1.15
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//
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//-----------------------------------------------------------------------------
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Word16 cos_fxp(Word16 x);
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//-----------------------------------------------------------------------------
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// PURPOSE:
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// Computes the sinus of x whose value is expressed in radians/PI.
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//
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// INPUT:
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// x - argument in Q1.15
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//
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// OUTPUT:
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// None
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//
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// RETURN:
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// Result in Q1.15
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//
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//-----------------------------------------------------------------------------
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Word16 sin_fxp(Word16 x);
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//-----------------------------------------------------------------------------
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// PURPOSE:
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// Multiply a 32 bit number (L_var2) and a 16 bit
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// number (var1) returning a 32 bit result. L_var2
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// is truncated to 31 bits prior to executing the
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// multiply.
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//
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// INPUT:
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// L_var2 - A Word32 input variable
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// var1 - A Word16 input variable
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//
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// OUTPUT:
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// None
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//
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// RETURN:
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// A Word32 value
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//
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//-----------------------------------------------------------------------------
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Word32 L_mpy_ls(Word32 L_var2, Word16 var1);
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//-----------------------------------------------------------------------------
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// PURPOSE:
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// Computes pow(2.0, x)
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//
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// INPUT:
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// x - In signed Q10.22 format
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//
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// OUTPUT:
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// None
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//
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// RETURN:
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// Result in signed Q14.2 format
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//
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//-----------------------------------------------------------------------------
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Word16 Pow2 (Word32 x);
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//-----------------------------------------------------------------------------
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// PURPOSE:
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// Computes sqrt(L_x), where L_x is positive.
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//
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// INPUT:
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// L_x - argument in Q1.31
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// *exp - pointer to save denormalization exponent
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// OUTPUT:
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// Right shift to be applied to result, Q16.0
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//
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// RETURN:
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// Result in Q1.31
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// Right shift should be applied to it!
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//
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//-----------------------------------------------------------------------------
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Word32 sqrt_l_exp (Word32 L_x, Word16 *exp);
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//-----------------------------------------------------------------------------
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// PURPOSE:
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// Computes log2 of x
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//
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// INPUT:
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// x - argument in Q14.2
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//
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// OUTPUT:
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// None
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//
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// RETURN:
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// Result in Q10.22
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//
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//-----------------------------------------------------------------------------
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Word32 Log2(Word16 x);
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#endif
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