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/* origin: FreeBSD /usr/src/lib/msun/src/s_ctanhf.c */
/*-
* Copyright (c) 2011 David Schultz
* 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 unmodified, 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 ``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 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.
*/
/*
* Hyperbolic tangent of a complex argument z. See s_ctanh.c for details.
*/
#include "libm.h"
float complex ctanhf(float complex z)
{
float x, y;
float t, beta, s, rho, denom;
uint32_t hx, ix;
x = crealf(z);
y = cimagf(z);
GET_FLOAT_WORD(hx, x);
ix = hx & 0x7fffffff;
if (ix >= 0x7f800000) {
if (ix & 0x7fffff)
return CMPLXF(x, (y == 0 ? y : x * y));
SET_FLOAT_WORD(x, hx - 0x40000000);
return CMPLXF(x, copysignf(0, isinf(y) ? y : sinf(y) * cosf(y)));
}
if (!isfinite(y))
return CMPLXF(y - y, y - y);
if (ix >= 0x41300000) { /* x >= 11 */
float exp_mx = expf(-fabsf(x));
return CMPLXF(copysignf(1, x), 4 * sinf(y) * cosf(y) * exp_mx * exp_mx);
}
t = tanf(y);
beta = 1.0 + t * t;
s = sinhf(x);
rho = sqrtf(1 + s * s);
denom = 1 + beta * s * s;
return CMPLXF((beta * rho * s) / denom, t / denom);
}
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