/* ----------------------------------------------------------------------
* Copyright (C) 2010-2014 ARM Limited. All rights reserved.
*
* $Date: 16/10/14 6:01p $Revision:  V.1.4.5
*
* Project:      CMSIS DSP Library
* Title:        arm_sin_cos_f32.c
*
* Description:  Sine and Cosine calculation for floating-point values.
*
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
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*     notice, this list of conditions and the following disclaimer.
*   - Redistributions in binary form must reproduce the above copyright
*     notice, this list of conditions and the following disclaimer in
*     the documentation and/or other materials provided with the
*     distribution.
*   - Neither the name of ARM LIMITED nor the names of its contributors
*     may be used to endorse or promote products derived from this
*     software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* -------------------------------------------------------------------- */

#include "arm_math.h"
#include "arm_common_tables.h"

/**
 * @ingroup groupController
 */

/**
 * @defgroup SinCos Sine Cosine
 *
 * Computes the trigonometric sine and cosine values using a combination of table lookup
 * and linear interpolation.
 * There are separate functions for Q31 and floating-point data types.
 * The input to the floating-point version is in degrees while the
 * fixed-point Q31 have a scaled input with the range
 * [-1 0.9999] mapping to [-180 +180] degrees.
 *
 * The floating point function also allows values that are out of the usual range. When this happens, the function will
 * take extra time to adjust the input value to the range of [-180 180].
 *
 * The implementation is based on table lookup using 360 values together with linear interpolation.
 * The steps used are:
 *  -# Calculation of the nearest integer table index.
 *  -# Compute the fractional portion (fract) of the input.
 *  -# Fetch the value corresponding to \c index from sine table to \c y0 and also value from \c index+1 to \c y1.
 *  -# Sine value is computed as <code> *psinVal = y0 + (fract * (y1 - y0))</code>.
 *  -# Fetch the value corresponding to \c index from cosine table to \c y0 and also value from \c index+1 to \c y1.
 *  -# Cosine value is computed as <code> *pcosVal = y0 + (fract * (y1 - y0))</code>.
 */

/**
* @addtogroup SinCos
* @{
*/

/**
 * @brief  Floating-point sin_cos function.
 * @param[in]  theta    input value in degrees
 * @param[out] *pSinVal points to the processed sine output.
 * @param[out] *pCosVal points to the processed cos output.
 * @return none.
 */

void arm_sin_cos_f32(
    float32_t theta,
    float32_t * pSinVal,
    float32_t * pCosVal)
{
    float32_t fract, in;                             /* Temporary variables for input, output */
    uint16_t indexS, indexC;                         /* Index variable */
    float32_t f1, f2, d1, d2;                        /* Two nearest output values */
    int32_t n;
    float32_t findex, Dn, Df, temp;

    /* input x is in degrees */
    /* Scale the input, divide input by 360, for cosine add 0.25 (pi/2) to read sine table */
    in = theta * 0.00277777777778f;

    /* Calculation of floor value of input */
    n = (int32_t) in;

    /* Make negative values towards -infinity */
    if(in < 0.0f)
    {
        n--;
    }
    /* Map input value to [0 1] */
    in = in - (float32_t) n;

    /* Calculation of index of the table */
    findex = (float32_t) FAST_MATH_TABLE_SIZE * in;
    indexS = ((uint16_t)findex) & 0x1ff;
    indexC = (indexS + (FAST_MATH_TABLE_SIZE / 4)) & 0x1ff;

    /* fractional value calculation */
    fract = findex - (float32_t) indexS;

    /* Read two nearest values of input value from the cos & sin tables */
    f1 = sinTable_f32[indexC + 0];
    f2 = sinTable_f32[indexC + 1];
    d1 = -sinTable_f32[indexS + 0];
    d2 = -sinTable_f32[indexS + 1];

    Dn = 0.0122718463030f; // delta between the two points (fixed), in this case 2*pi/FAST_MATH_TABLE_SIZE
    Df = f2 - f1; // delta between the values of the functions
    temp = Dn * (d1 + d2) - 2 * Df;
    temp = fract * temp + (3 * Df - (d2 + 2 * d1) * Dn);
    temp = fract * temp + d1 * Dn;

    /* Calculation of cosine value */
    *pCosVal = fract * temp + f1;

    /* Read two nearest values of input value from the cos & sin tables */
    f1 = sinTable_f32[indexS + 0];
    f2 = sinTable_f32[indexS + 1];
    d1 = sinTable_f32[indexC + 0];
    d2 = sinTable_f32[indexC + 1];

    Df = f2 - f1; // delta between the values of the functions
    temp = Dn * (d1 + d2) - 2 * Df;
    temp = fract * temp + (3 * Df - (d2 + 2 * d1) * Dn);
    temp = fract * temp + d1 * Dn;

    /* Calculation of sine value */
    *pSinVal = fract * temp + f1;
}
/**
 * @} end of SinCos group
 */
