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/*-
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright (c) 2019 Steven G. Kargl <kargl@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.
*/
#include <sys/cdefs.h>
#include <complex.h>
#include <float.h>
#include <math.h>
#include "fpmath.h"
#include "math_private.h"
#include "k_expl.h"
/* XXX cexpl() should be converted to use bits likeo src/s_cexp.c. */
static const long double
cexp_ovfl = 2.27892930024498818830197576893019292e+04L,
exp_ovfl = 1.13565234062941439494919310779707649e+04L;
long double complex
cexpl(long double complex z)
{
long double c, exp_x, s, x, y;
x = creall(z);
y = cimagl(z);
/* cexp(x + I 0) = exp(x) + I 0 */
if (y == 0)
return (CMPLXL(expl(x), y));
/* cexp(0 + I y) = cos(y) + I sin(y) */
if (x == 0) {
sincosl(y, &s, &c);
return (CMPLXL(c, s));
}
if (!isfinite(y)) {
if (isfinite(x) || isnan(x)) {
/* cexp(finite|NaN +- I Inf|NaN) = NaN + I NaN */
return (CMPLXL(y - y, y - y));
} else if (isinf(x) && copysignl(1.L, x) < 0) {
/* cexp(-Inf +- I Inf|NaN) = 0 + I 0 */
return (CMPLXL(0.0, 0.0));
} else {
/* cexp(+Inf +- I Inf|NaN) = Inf + I NaN */
return (CMPLXL(x, y - y));
}
}
if (x > exp_ovfl && x < cexp_ovfl) {
/*
* x is between exp_ovfl and cexp_ovfl, so we must scale to
* avoid overflow in exp(x).
*/
return (__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);
return (CMPLXL(exp_x * c, exp_x * s));
}
}
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