ctanhf.c revision 25c28e83beb90e7c80452a7c818c5e6f73a07dc8
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2011 Nexenta Systems, Inc. All rights reserved.
*/
/*
* Copyright 2006 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#pragma weak ctanhf = __ctanhf
#include "libm.h" /* expf/expm1f/fabsf/sincosf/sinf/tanhf */
#include "complex_wrapper.h"
/* INDENT OFF */
static const float four = 4.0F, two = 2.0F, one = 1.0F, zero = 0.0F;
/* INDENT ON */
fcomplex
ctanhf(fcomplex z) {
float r, u, v, t, x, y, S, C;
int hx, ix, hy, iy;
fcomplex ans;
x = F_RE(z);
y = F_IM(z);
hx = THE_WORD(x);
ix = hx & 0x7fffffff;
hy = THE_WORD(y);
iy = hy & 0x7fffffff;
x = fabsf(x);
y = fabsf(y);
if (iy == 0) { /* ctanh(x,0) = (x,0) for x = 0 or NaN */
F_RE(ans) = tanhf(x);
F_IM(ans) = zero;
} else if (iy >= 0x7f800000) { /* y is inf or NaN */
if (ix < 0x7f800000) /* catanh(finite x,inf/nan) is nan */
F_RE(ans) = F_IM(ans) = y - y;
else if (ix == 0x7f800000) { /* x is inf */
F_RE(ans) = one;
F_IM(ans) = zero;
} else {
F_RE(ans) = x + y;
F_IM(ans) = y - y;
}
} else if (ix >= 0x41600000) {
/*
* |x| > 14 = prec/2 (14,28,34,60)
* ctanh z ~ 1 + i (sin2y)/(exp(2x))
*/
F_RE(ans) = one;
if (iy < 0x7f000000) /* t = sin(2y) */
S = sinf(y + y);
else {
(void) sincosf(y, &S, &C);
S = (S + S) * C;
}
if (ix >= 0x7f000000) { /* |x| > max/2 */
if (ix >= 0x7f800000) { /* |x| is inf or NaN */
if (ix > 0x7f800000) /* x is NaN */
F_RE(ans) = F_IM(ans) = x + y;
else
F_IM(ans) = zero * S; /* x is inf */
} else
F_IM(ans) = S * expf(-x); /* underflow */
} else
F_IM(ans) = (S + S) * expf(-(x + x));
/* 2 sin 2y / exp(2x) */
} else {
/* INDENT OFF */
/*
* t*t+2t
* ctanh z = ---------------------------
* t*t+[4(t+1)(cos y)](cos y)
*
* [4(t+1)(cos y)]*(sin y)
* i --------------------------
* t*t+[4(t+1)(cos y)](cos y)
*/
/* INDENT ON */
(void) sincosf(y, &S, &C);
t = expm1f(x + x);
r = (four * C) * (t + one);
u = t * t;
v = one / (u + r * C);
F_RE(ans) = (u + two * t) * v;
F_IM(ans) = (r * S) * v;
}
if (hx < 0)
F_RE(ans) = -F_RE(ans);
if (hy < 0)
F_IM(ans) = -F_IM(ans);
return (ans);
}