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/* ------------------------------------------------------------------
* 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.
* -------------------------------------------------------------------
*/
/*
Filename: pv_sine.c
------------------------------------------------------------------------------
REVISION HISTORY
Who: Date: MM/DD/YYYY
Description:
------------------------------------------------------------------------------
INPUT AND OUTPUT DEFINITIONS
Int32 x 32-bit integer angle (in Q30) between 0 and pi/2
------------------------------------------------------------------------------
FUNCTION DESCRIPTION
Find the sine of a number between 0 and pi/2
------------------------------------------------------------------------------
REQUIREMENTS
------------------------------------------------------------------------------
REFERENCES
------------------------------------------------------------------------------
PSEUDO-CODE
------------------------------------------------------------------------------
*/
/*----------------------------------------------------------------------------
; INCLUDES
----------------------------------------------------------------------------*/
#ifdef AAC_PLUS
#ifdef PARAMETRICSTEREO
#include "pv_audio_type_defs.h"
#include "fxp_mul32.h"
#include "pv_sine.h"
/*----------------------------------------------------------------------------
; MACROS
; Define module specific macros here
----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------
; DEFINES
; Include all pre-processor statements here. Include conditional
; compile variables also.
----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------
; LOCAL FUNCTION DEFINITIONS
; Function Prototype declaration
----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------
; LOCAL STORE/BUFFER/POINTER DEFINITIONS
; Variable declaration - defined here and used outside this module
----------------------------------------------------------------------------*/
#define R_SHIFT 30
#define Q_fmt(x) (Int32)(x*((Int32)1<<R_SHIFT) + (x>=0?0.5F:-0.5F))
const Int32 sin_table[9] =
{
Q_fmt(0.00001724684028), Q_fmt(-0.00024606242846),
Q_fmt(0.00007297328923), Q_fmt(0.00826706596417),
Q_fmt(0.00003585160465), Q_fmt(-0.16667772526248),
Q_fmt(0.00000174197440), Q_fmt(0.99999989138797),
Q_fmt(0.00000000110513)
};
/*----------------------------------------------------------------------------
; EXTERNAL FUNCTION REFERENCES
; Declare functions defined elsewhere and referenced in this module
----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------
; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES
; Declare variables used in this module but defined elsewhere
----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------
; FUNCTION CODE
----------------------------------------------------------------------------*/
Int32 pv_sine(Int32 z)
{
Int32 sine;
Int32 i;
const Int32 *pt_table = sin_table;
Int32 sign = 0;
if (z < 0)
{
z = -z;
sign = 1;
}
if (z > Q_fmt(0.0015))
{
sine = fxp_mul32_Q30(*(pt_table++), z);
for (i = 7; i != 0; i--)
{
sine += *(pt_table++);
sine = fxp_mul32_Q30(sine, z);
}
}
else
{
sine = z; /* better approximation in this range */
}
if (sign)
{
sine = -sine;
}
return sine;
}
Int32 pv_cosine(Int32 z)
{
Int32 cosine;
if (z < 0)
{
z = -z; /* sign does not play a role in cosine */
}
if (z > Q_fmt(0.0015))
{
z = Q_fmt(1.57079632679490) - z; /* pi/2 - z */
cosine = pv_sine(z);
}
else
{ /* better approximation in this range */
cosine = Q_fmt(0.99999999906868) - (fxp_mul32_Q30(z, z) >> 1);
}
return cosine;
}
#endif
#endif
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