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/* PROLOG END TAG zYx                                              */
#ifdef __SPU__
#ifndef _ASINHF4_H_
#define _ASINHF4_H_ 1

#include <spu_intrinsics.h>

#include "logf4.h"
#include "sqrtf4.h"

/*
 * FUNCTION
 *  vector float _asinhf4(vector float x)
 *
 * DESCRIPTION
 *  The asinhf4 function returns a vector containing the hyperbolic
 *  arcsines of the corresponding elements of the input vector.
 *
 *  We are using the formula:
 *    asinh = ln(|x| + sqrt(x^2 + 1))
 *  and the anti-symmetry of asinh.
 *
 *  For x near zero, we use the Taylor series:
 *
 *                infinity
 *                 ------
 *                  -   '  P  (0)
 *                   -      k-1    k
 *    asinh x =       -    -----  x
 *                   -       k
 *                  -   ,
 *                 ------
 *                 k = 1
 *
 *  Special Cases:
 *   - asinh(+0)        returns +0
 *   - asinh(-0)        returns -0
 *   - Normally,  asinh(+/- infinity) returns +/- infinity,
 *	   but on the SPU, single-precision infinity is not supported,
 *	   so it is treated as a normal number here.
 *
 */

/*
 * Maclaurin Series Coefficients
 * for x near 0.
 */
#define ASINH_MAC01 1.0000000000000000000000000000000000000000000000000000000000000000000000E0
#define ASINH_MAC03 -1.6666666666666666666666666666666666666666666666666666666666666666666667E-1
#define ASINH_MAC05 7.5000000000000000000000000000000000000000000000000000000000000000000000E-2
#define ASINH_MAC07 -4.4642857142857142857142857142857142857142857142857142857142857142857143E-2
#define ASINH_MAC09 3.0381944444444444444444444444444444444444444444444444444444444444444444E-2
#define ASINH_MAC11 -2.2372159090909090909090909090909090909090909090909090909090909090909091E-2
#define ASINH_MAC13 1.7352764423076923076923076923076923076923076923076923076923076923076923E-2
#define ASINH_MAC15 -1.3964843750000000000000000000000000000000000000000000000000000000000000E-2
#define ASINH_MAC17 1.1551800896139705882352941176470588235294117647058823529411764705882353E-2
#define ASINH_MAC19 -9.7616095291940789473684210526315789473684210526315789473684210526315789E-3
#define ASINH_MAC21 8.3903358096168154761904761904761904761904761904761904761904761904761905E-3
#define ASINH_MAC23 -7.3125258735988451086956521739130434782608695652173913043478260869565217E-3
#define ASINH_MAC25 6.4472103118896484375000000000000000000000000000000000000000000000000000E-3
#define ASINH_MAC27 -5.7400376708419234664351851851851851851851851851851851851851851851851852E-3
#define ASINH_MAC29 5.1533096823199041958512931034482758620689655172413793103448275862068966E-3
#define ASINH_MAC31 -4.6601434869150961599042338709677419354838709677419354838709677419354839E-3
#if 0
#define ASINH_MAC33 4.2409070936793630773370916193181818181818181818181818181818181818181818E-3
#define ASINH_MAC35 -3.8809645588376692363194056919642857142857142857142857142857142857142857E-3
#define ASINH_MAC37 3.5692053938259345454138678473395270270270270270270270270270270270270270E-3
#define ASINH_MAC39 -3.2970595034734847453924325796274038461538461538461538461538461538461538E-3
#define ASINH_MAC41 3.0578216492580306693548109473251714939024390243902439024390243902439024E-3
#define ASINH_MAC43 -2.8461784011089421678767647854117460029069767441860465116279069767441860E-3
#endif

static __inline vector float
_asinhf4(vector float x)
{
    vec_float4 sign_mask = spu_splats(-0.0f);
    vec_float4 onef = spu_splats(1.0f);
    vec_uint4  oneu = spu_splats(1u);
    vec_uint4  twou = spu_splats(2u);
    vec_uint4  threeu = spu_splats(3u);
    vec_float4 ln2 = spu_splats(6.931471805599453094172321E-1f);
    vec_float4 largef = spu_splats(9.21e18f);
    vec_float4 result, fresult, mresult;
    vec_float4 xabs, xsqu;
    /* Where we switch from maclaurin to formula */
    vec_float4 switch_approx = spu_splats(0.74f);
    vec_float4 trunc_part2 = spu_splats(20.0f);
    vec_uint4  truncadd;
    vec_uint4  islarge;
    vec_uint4  use_form;

    xabs = spu_andc(x, sign_mask);
    xsqu = spu_mul(x, x);
    islarge = spu_cmpgt(xabs, largef);

    /*
     * Formula:
     *   asinh = ln(|x| + sqrt(x^2 + 1))
     */

    vec_float4 logarg = spu_add(xabs, _sqrtf4(spu_madd(xabs, xabs, onef)));
    logarg = spu_sel(logarg, xabs, islarge);
    fresult = _logf4(logarg);
    fresult = spu_sel(fresult, spu_add(fresult, ln2), islarge);

    /*
     * Maclaurin Series
     */
    mresult = spu_madd(xsqu, spu_splats((float)ASINH_MAC31), spu_splats((float)ASINH_MAC29));
    mresult = spu_madd(xsqu, mresult, spu_splats((float)ASINH_MAC27));
    mresult = spu_madd(xsqu, mresult, spu_splats((float)ASINH_MAC25));
    mresult = spu_madd(xsqu, mresult, spu_splats((float)ASINH_MAC23));
    mresult = spu_madd(xsqu, mresult, spu_splats((float)ASINH_MAC21));
    mresult = spu_madd(xsqu, mresult, spu_splats((float)ASINH_MAC19));
    mresult = spu_madd(xsqu, mresult, spu_splats((float)ASINH_MAC17));
    mresult = spu_madd(xsqu, mresult, spu_splats((float)ASINH_MAC15));
    mresult = spu_madd(xsqu, mresult, spu_splats((float)ASINH_MAC13));
    mresult = spu_madd(xsqu, mresult, spu_splats((float)ASINH_MAC11));
    mresult = spu_madd(xsqu, mresult, spu_splats((float)ASINH_MAC09));
    mresult = spu_madd(xsqu, mresult, spu_splats((float)ASINH_MAC07));
    mresult = spu_madd(xsqu, mresult, spu_splats((float)ASINH_MAC05));
    mresult = spu_madd(xsqu, mresult, spu_splats((float)ASINH_MAC03));
    mresult = spu_madd(xsqu, mresult, spu_splats((float)ASINH_MAC01));
    mresult = spu_mul(xabs, mresult);

    /*
     * Choose between series and formula
     */
    use_form = spu_cmpgt(xabs, switch_approx);
    result = spu_sel(mresult, fresult, use_form);

    /*
     * Truncation correction on spu
     */
    truncadd = spu_sel(oneu, threeu, use_form);
    truncadd = spu_sel(truncadd, twou, spu_cmpgt(xabs, trunc_part2));
    result = (vec_float4)spu_add((vec_uint4)result, truncadd);

    /* Preserve sign - asinh is anti-symmetric */
    result = spu_sel(result, x, (vec_uint4)sign_mask);

    return result;
}

#endif /* _ASINHF4_H_ */
#endif /* __SPU__ */
