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/* PROLOG END TAG zYx                                              */
#ifdef __SPU__
#ifndef _COSHD2_H_
#define _COSHD2_H_ 1

#include <spu_intrinsics.h>

#include "expd2.h"
#include "recipd2.h"

/*
 * FUNCTION
 *	vector float _coshd2(vector double angle)
 *
 * DESCRIPTION
 *	_coshd2 computes the hyperbolic cosines of a vector of angles
 *      (expressed in radians) to an accuracy of a double precision
 *      floating point.
 */
static __inline vector double
_coshd2(vector double x)
{

    // Coefficents for the power series
    vec_double2 f02 = spu_splats(5.00000000000000000000E-1);  // 1/(2!)
    vec_double2 f04 = spu_splats(4.16666666666666666667E-2);  // 1/(4!)
    vec_double2 f06 = spu_splats(1.38888888888888888889E-3);  // 1/(6!)
    vec_double2 f08 = spu_splats(2.48015873015873015873E-5);  // 1/(8!)
    vec_double2 f10 = spu_splats(2.75573192239858906526E-7);  // 1/(10!)
    vec_double2 f12 = spu_splats(2.08767569878680989792E-9);  // 1/(12!)
    vec_double2 f14 = spu_splats(1.14707455977297247139E-11); // 1/(14!)
    vec_double2 f16 = spu_splats(4.77947733238738529744E-14); // 1/(16!)
    vec_double2 f18 = spu_splats(1.56192069685862264622E-16); // 1/(18!)
    vec_double2 f20 = spu_splats(4.11031762331216485848E-19); // 1/(20!)
    vec_double2 f22 = spu_splats(8.89679139245057328675E-22); // 1/(22!)

    //  Check if the input is within the range [ -1.0 ... 1.0 ]
    //  If it is, we want to use the power series, otherwise
    //  we want to use the 0.5 * (e^x + e^-x)

    // round to float, check if within range.  Results will be in
    // slots 0 and 2, so we rotate right 4 bytes, and "or" with ourself
    // to produce 64 bits of all 1's or 0's.
    vec_uint4   use_exp = spu_cmpabsgt(spu_roundtf(x), spu_splats(1.0f));
    use_exp = spu_or(use_exp, spu_rlmaskqwbyte(use_exp, -4));

    // Perform the calculation of the power series using Horner's method
    vec_double2 result;
    vec_double2 x2 = spu_mul(x, x);
    result = spu_madd(x2, f22, f20);
    result = spu_madd(x2, result, f18);
    result = spu_madd(x2, result, f16);
    result = spu_madd(x2, result, f14);
    result = spu_madd(x2, result, f12);
    result = spu_madd(x2, result, f10);
    result = spu_madd(x2, result, f08);
    result = spu_madd(x2, result, f06);
    result = spu_madd(x2, result, f04);
    result = spu_madd(x2, result, f02);
    result = spu_madd(x2, result, spu_splats(1.0));

    //  Perform calculation as a function of 0.5 * (e^x + e^-x)
    vec_double2 ex = _expd2(x);
    vec_double2 ex_inv = _recipd2(ex);

    vec_double2 r2 = spu_add(ex, ex_inv);
    r2 = spu_mul(r2, f02); // we can reuse f02 here

    //  Select either the power series or exp version
    result = spu_sel(result, r2, (vec_ullong2)use_exp);

    return result;
}

#endif /* _COSHD2_H_ */
#endif /* __SPU__ */
