Home | History | Annotate | Download | only in src
      1 /*-
      2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
      3  *
      4  * Copyright (c) 2011 David Schultz
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice unmodified, this list of conditions, and the following
     12  *    disclaimer.
     13  * 2. Redistributions in binary form must reproduce the above copyright
     14  *    notice, this list of conditions and the following disclaimer in the
     15  *    documentation and/or other materials provided with the distribution.
     16  *
     17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     27  */
     28 
     29 /*
     30  * Hyperbolic tangent of a complex argument z.  See s_ctanh.c for details.
     31  */
     32 
     33 #include <sys/cdefs.h>
     34 __FBSDID("$FreeBSD: head/lib/msun/src/s_ctanhf.c 336362 2018-07-17 07:42:14Z bde $");
     35 
     36 #include <complex.h>
     37 #include <math.h>
     38 
     39 #include "math_private.h"
     40 
     41 float complex
     42 ctanhf(float complex z)
     43 {
     44 	float x, y;
     45 	float t, beta, s, rho, denom;
     46 	uint32_t hx, ix;
     47 
     48 	x = crealf(z);
     49 	y = cimagf(z);
     50 
     51 	GET_FLOAT_WORD(hx, x);
     52 	ix = hx & 0x7fffffff;
     53 
     54 	if (ix >= 0x7f800000) {
     55 		if (ix & 0x7fffff)
     56 			return (CMPLXF(nan_mix(x, y),
     57 			    y == 0 ? y : nan_mix(x, y)));
     58 		SET_FLOAT_WORD(x, hx - 0x40000000);
     59 		return (CMPLXF(x,
     60 		    copysignf(0, isinf(y) ? y : sinf(y) * cosf(y))));
     61 	}
     62 
     63 	if (!isfinite(y))
     64 		return (CMPLXF(y - y, y - y));
     65 
     66 	if (ix >= 0x41300000) {	/* |x| >= 11 */
     67 		float exp_mx = expf(-fabsf(x));
     68 		return (CMPLXF(copysignf(1, x),
     69 		    4 * sinf(y) * cosf(y) * exp_mx * exp_mx));
     70 	}
     71 
     72 	t = tanf(y);
     73 	beta = 1.0 + t * t;
     74 	s = sinhf(x);
     75 	rho = sqrtf(1 + s * s);
     76 	denom = 1 + beta * s * s;
     77 	return (CMPLXF((beta * rho * s) / denom, t / denom));
     78 }
     79 
     80 float complex
     81 ctanf(float complex z)
     82 {
     83 
     84 	z = ctanhf(CMPLXF(cimagf(z), crealf(z)));
     85 	return (CMPLXF(cimagf(z), crealf(z)));
     86 }
     87 
     88