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/* PROLOG END TAG zYx                                              */

#ifdef __SPU__

#ifndef _ACOSHF4_H_

#define _ACOSHF4_H_     1

#include <spu_intrinsics.h>

#include "logf4.h"

#include "sqrtf4.h"

/*

 * FUNCTION

 *  vector float _acoshf4(vector float x)

 *

 * DESCRIPTION

 *  The acoshf4 function returns a vector containing the hyperbolic

 *  arccosines of the corresponding elements of the input vector.

 *

 *  We are using the formula:

 *    acosh = ln(x + sqrt(x^2 - 1))

 *

 *  For x near one, we use the Taylor series:

 *

 *                infinity

 *                 ------

 *                  -   '

 *                   -                 k

 *    acosh x =       -      C  (x - 1)

 *                   -        k

 *                  -   ,

 *                 ------

 *                 k = 0

 *

 *

 *  Special Cases:

 *      - acosh(1)        = +0

 *      - NaNs and Infinity aren't supported for single-precision on SPU.

 *

 */

/*

 * Taylor Series Coefficients

 * for x around 1.

 */

#define SDM_ACOSHF4_TAY01  1.00000000000000000000000000000000000E0f  /* 1 / 1                            */

#define SDM_ACOSHF4_TAY02 -8.33333333333333333333333333333333333E-2f /* 1 / 12                           */

#define SDM_ACOSHF4_TAY03  1.87500000000000000000000000000000000E-2f /* 3 / 160                          */

#define SDM_ACOSHF4_TAY04 -5.58035714285714285714285714285714286E-3f /* 5 / 896                          */

#define SDM_ACOSHF4_TAY05  1.89887152777777777777777777777777778E-3f /* 35 / 18432                       */

#define SDM_ACOSHF4_TAY06 -6.99129971590909090909090909090909091E-4f /* 63 / 90112                       */

#define SDM_ACOSHF4_TAY07  2.71136944110576923076923076923076923E-4f /* 231 / 851968                     */

#define SDM_ACOSHF4_TAY08 -1.09100341796875000000000000000000000E-4f /* 143 / 1310720                    */

#define SDM_ACOSHF4_TAY09  4.51242222505457261029411764705882353E-5f /* 6435 / 142606336                 */

#define SDM_ACOSHF4_TAY10 -1.90656436117071854440789473684210526E-5f /* 12155 / 637534208                */

#define SDM_ACOSHF4_TAY11  8.19368731407892136346726190476190476E-6f /* 46189 / 5637144576               */

#define SDM_ACOSHF4_TAY12 -3.57056927421818608823029891304347826E-6f /* 88179 / 24696061952              */

#define SDM_ACOSHF4_TAY13  1.57402595505118370056152343750000000E-6f /* 676039 / 429496729600            */

#define SDM_ACOSHF4_TAY14 -7.00688192241445735648826316550925926E-7f /* 1300075 / 1855425871872          */

#define SDM_ACOSHF4_TAY15  3.14533061665033215078814276333512931E-7f /* 5014575 / 15942918602752         */

#if 0

#define SDM_ACOSHF4_TAY16 -1.42216292935641362301764949675529234E-7f /* 9694845 / 68169720922112         */

#define SDM_ACOSHF4_TAY17  6.47111067761133282064375552264126864E-8f /* 100180065 / 1548112371908608     */

#define SDM_ACOSHF4_TAY18 -2.96094097811711825280716376645224435E-8f /* 116680311 / 3940649673949184     */

#define SDM_ACOSHF4_TAY19  1.36154380562817937676005090612011987E-8f /* 2268783825 / 166633186212708352  */

#endif

static __inline vector float _acoshf4(vector float x)

{

    vec_float4 minus_onef = spu_splats(-1.0f);

    vec_float4 twof       = spu_splats(2.0f);

    vec_float4 largef     = spu_splats(2.5e19f);

    vec_float4 xminus1;

    /* Where we switch from taylor to formula */

    vec_float4  switch_approx = spu_splats(2.0f);

    vec_uint4   use_form;

    vec_float4 result, fresult, mresult;;

    /*

     * Formula:

     *   acosh = ln(x + sqrt(x^2 - 1))

     */

    fresult = _sqrtf4(spu_madd(x, x, minus_onef));

    fresult = spu_add(x, spu_sel(fresult, x, spu_cmpgt(x, largef)));

    fresult = _logf4(fresult);

    fresult = (vec_float4)spu_add((vec_uint4)fresult, spu_splats(2u));

    /*

     * Taylor Series

     */

    xminus1 = spu_add(x, minus_onef);

    mresult = spu_splats(SDM_ACOSHF4_TAY15);

    mresult = spu_madd(xminus1, mresult, spu_splats(SDM_ACOSHF4_TAY14));

    mresult = spu_madd(xminus1, mresult, spu_splats(SDM_ACOSHF4_TAY13));

    mresult = spu_madd(xminus1, mresult, spu_splats(SDM_ACOSHF4_TAY12));

    mresult = spu_madd(xminus1, mresult, spu_splats(SDM_ACOSHF4_TAY11));

    mresult = spu_madd(xminus1, mresult, spu_splats(SDM_ACOSHF4_TAY10));

    mresult = spu_madd(xminus1, mresult, spu_splats(SDM_ACOSHF4_TAY09));

    mresult = spu_madd(xminus1, mresult, spu_splats(SDM_ACOSHF4_TAY08));

    mresult = spu_madd(xminus1, mresult, spu_splats(SDM_ACOSHF4_TAY07));

    mresult = spu_madd(xminus1, mresult, spu_splats(SDM_ACOSHF4_TAY06));

    mresult = spu_madd(xminus1, mresult, spu_splats(SDM_ACOSHF4_TAY05));

    mresult = spu_madd(xminus1, mresult, spu_splats(SDM_ACOSHF4_TAY04));

    mresult = spu_madd(xminus1, mresult, spu_splats(SDM_ACOSHF4_TAY03));

    mresult = spu_madd(xminus1, mresult, spu_splats(SDM_ACOSHF4_TAY02));

    mresult = spu_madd(xminus1, mresult, spu_splats(SDM_ACOSHF4_TAY01));

    mresult = spu_mul(mresult, _sqrtf4(spu_mul(xminus1, twof)));

    mresult = (vec_float4)spu_add((vec_uint4)mresult, spu_splats(1u));

    /*

     * Select series or formula

     */

    use_form = spu_cmpgt(x, switch_approx);

    result = spu_sel(mresult, fresult, use_form);

    return result;

}

#endif /* _ACOSHF4_H_ */

#endif /* __SPU__ */