/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2011 David Schultz <das@FreeBSD.ORG>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * src/s_cexp.c converted to long double complex by Steven G. Kargl
 */

#include <complex.h>
#include <float.h>
#ifdef __i386__
#include <ieeefp.h>
#endif

#include "fpmath.h"
#include "math.h"
#include "math_private.h"
#include "k_expl.h"

long double complex
cexpl (long double complex z)
{
        long double c, exp_x, s, x, y;
        uint64_t lx, ly;
        uint16_t hx, hy;

        ENTERI();

        x = creall(z);
        y = cimagl(z);

        EXTRACT_LDBL80_WORDS(hy, ly, y);
        hy &= 0x7fff;

        /* cexp(x + I 0) = exp(x) + I 0 */
        if ((hy | ly) == 0)
                RETURNI(CMPLXL(expl(x), y));
        EXTRACT_LDBL80_WORDS(hx, lx, x);
        /* cexp(0 + I y) = cos(y) + I sin(y) */
        if (((hx & 0x7fff) | lx) == 0) {
                sincosl(y, &s, &c);
                RETURNI(CMPLXL(c, s));
        }

        if (hy >= 0x7fff) {
                if ((hx & 0x7fff) < 0x7fff || ((hx & 0x7fff) == 0x7fff &&
                    (lx & 0x7fffffffffffffffULL) != 0)) {
                        /* cexp(finite|NaN +- I Inf|NaN) = NaN + I NaN */
                        RETURNI(CMPLXL(y - y, y - y));
                } else if (hx & 0x8000) {
                        /* cexp(-Inf +- I Inf|NaN) = 0 + I 0 */
                        RETURNI(CMPLXL(0.0, 0.0));
                } else {
                        /* cexp(+Inf +- I Inf|NaN) = Inf + I NaN */
                        RETURNI(CMPLXL(x, y - y));
                }
        }

        /*
         *  exp_ovfl = 11356.5234062941439497
         * cexp_ovfl = 22755.3287906024445633
         */
        if ((hx == 0x400c && lx > 0xb17217f7d1cf79acULL) ||
            (hx == 0x400d && lx < 0xb1c6a8573de9768cULL)) {
                /*
                 * x is between exp_ovfl and cexp_ovfl, so we must scale to
                 * avoid overflow in exp(x).
                 */
                RETURNI(__ldexp_cexpl(z, 0));
        } else {
                /*
                 * Cases covered here:
                 *  -  x < exp_ovfl and exp(x) won't overflow (common case)
                 *  -  x > cexp_ovfl, so exp(x) * s overflows for all s > 0
                 *  -  x = +-Inf (generated by exp())
                 *  -  x = NaN (spurious inexact exception from y)
                 */
                exp_x = expl(x);
                sincosl(y, &s, &c);
                RETURNI(CMPLXL(exp_x * c, exp_x * s));
        }
}