/*===--------------------------------------------------------------------------
 *                   ROCm Device Libraries
 *
 * This file is distributed under the University of Illinois Open Source
 * License. See LICENSE.TXT for details.
 *===------------------------------------------------------------------------*/

#include "mathD.h"

#define DOUBLE_SPECIALIZATION
#include "ep.h"

extern CONSTATTR double2 MATH_PRIVATE(epexpep)(double2 z);

CONSTATTR double2
MATH_MANGLE(ctanh)(double2 z)
{
    double cy;
    double sy = MATH_MANGLE(sincos)(z.y, &cy);
    double cysy = cy*sy;
    double x = BUILTIN_ABS_F64(z.x);

    double rr, ri;
    if (x < 0x1.419ecb712c481p+4) {
        double2 e = MATH_PRIVATE(epexpep)(sub(x, con(0x1.62e42fefa39efp-1,0x1.abc9e3b39803fp-56)));
        double2 er = rcp(e);
        er = ldx(er, -2);
        double2 cx = fadd(e, er);
        double2 sx = fsub(e, er);

        double cxhi = cx.hi;
        double sxhi = x < 0x1.0p-27 ? x : sx.hi;

        double d = MATH_MAD(cy, cy, sxhi*sxhi);
        rr = BUILTIN_COPYSIGN_F64(MATH_DIV(cxhi*sxhi, d), z.x);
        ri = MATH_DIV(cysy, d);
    } else {
        rr = BUILTIN_COPYSIGN_F64(1.0, z.x);
        ri = 4.0 * cysy * MATH_MANGLE(exp)(-2.0 * x);
    }

    if (!FINITE_ONLY_OPT()) {
        bool xn = BUILTIN_ISNAN_F64(x);
        bool yin = BUILTIN_CLASS_F64(z.y, CLASS_NINF|CLASS_PINF|CLASS_QNAN|CLASS_SNAN);
        bool ni = BUILTIN_CLASS_F64(x, CLASS_PZER|CLASS_PSUB|CLASS_PNOR) & yin;
        rr = (ni | xn) ? AS_DOUBLE(QNANBITPATT_DP64) : rr;
        ri = ni ? AS_DOUBLE(QNANBITPATT_DP64) : ri;
        ri = (BUILTIN_CLASS_F64(x, CLASS_PINF|CLASS_NINF) & yin) ? 0.0 : ri;
        ri = (xn & (z.y == 0.0)) ? z.y : ri;
    }

    return (double2)(rr, ri);
}