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/* PROLOG END TAG zYx                                              */
#ifdef __SPU__

#ifndef _COSD2_H_
#define _COSD2_H_ 1

#include <spu_intrinsics.h>

#include "cos_sin.h"

/*
 * FUNCTION
 *	vector double _cosd2(vector double angle)
 *
 * DESCRIPTION
 *	_cosd2 computes the cosine of a vector of angles (expressed
 *	in radians) to an accuracy of a double precision floating point.
 */
static __inline vector double
_cosd2(vector double angle)
{
    vec_int4    octant;
    vec_ullong2 select;
    vec_double2 cos, sin;
    vec_double2 toggle_sign, answer;

    /* Range reduce the input angle x into the range -PI/4 to PI/4
     * by performing simple modulus.
     */
    MOD_PI_OVER_FOUR(angle, octant);

    /* Compute the cosine and sine of the range reduced input.
     */
    COMPUTE_COS_SIN(angle, cos, sin);

    /* For each SIMD element, select which result (cos or sin) to use
     * with a sign correction depending upon the octant of the original
     * angle (Maclaurin series).
     *
     *   octants      angles     select  sign toggle
     *   -------   ------------  ------  -----------
     *     0          0 to 45     cos        no
     *    1,2        45 to 135    sin        yes
     *    3,4       135 to 225    cos        yes
     *    5,6       225 to 315    sin        no
     *     7        315 to 360    cos        no
     */
    octant = spu_shuffle(octant, octant,
                         ((vec_uchar16) { 0, 1, 2, 3, 0, 1, 2, 3, 8, 9, 10, 11, 8, 9, 10, 11 }));

    toggle_sign
        = (vec_double2)spu_sl(spu_and(spu_add(octant, 2), 4), ((vec_uint4) { 29, 32, 29, 32 }));
    select = (vec_ullong2)spu_cmpeq(spu_and(octant, 2), 0);

    answer = spu_xor(spu_sel(sin, cos, select), toggle_sign);

    return (answer);
}

#endif /* _COSD2_H_ */
#endif /* __SPU__ */
