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      1 /*-
      2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
      3  *
      4  * Copyright (c) 2005 Bruce D. Evans and Steven G. Kargl
      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  * Float version of ccosh().  See s_ccosh.c for details.
     31  */
     32 
     33 #include <sys/cdefs.h>
     34 __FBSDID("$FreeBSD: head/lib/msun/src/s_ccoshf.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 static const float huge = 0x1p127;
     42 
     43 float complex
     44 ccoshf(float complex z)
     45 {
     46 	float x, y, h;
     47 	int32_t hx, hy, ix, iy;
     48 
     49 	x = crealf(z);
     50 	y = cimagf(z);
     51 
     52 	GET_FLOAT_WORD(hx, x);
     53 	GET_FLOAT_WORD(hy, y);
     54 
     55 	ix = 0x7fffffff & hx;
     56 	iy = 0x7fffffff & hy;
     57 
     58 	if (ix < 0x7f800000 && iy < 0x7f800000) {
     59 		if (iy == 0)
     60 			return (CMPLXF(coshf(x), x * y));
     61 		if (ix < 0x41100000)	/* |x| < 9: normal case */
     62 			return (CMPLXF(coshf(x) * cosf(y), sinhf(x) * sinf(y)));
     63 
     64 		/* |x| >= 9, so cosh(x) ~= exp(|x|) */
     65 		if (ix < 0x42b17218) {
     66 			/* x < 88.7: expf(|x|) won't overflow */
     67 			h = expf(fabsf(x)) * 0.5F;
     68 			return (CMPLXF(h * cosf(y), copysignf(h, x) * sinf(y)));
     69 		} else if (ix < 0x4340b1e7) {
     70 			/* x < 192.7: scale to avoid overflow */
     71 			z = __ldexp_cexpf(CMPLXF(fabsf(x), y), -1);
     72 			return (CMPLXF(crealf(z), cimagf(z) * copysignf(1, x)));
     73 		} else {
     74 			/* x >= 192.7: the result always overflows */
     75 			h = huge * x;
     76 			return (CMPLXF(h * h * cosf(y), h * sinf(y)));
     77 		}
     78 	}
     79 
     80 	if (ix == 0)			/* && iy >= 0x7f800000 */
     81 		return (CMPLXF(y - y, x * copysignf(0, y)));
     82 
     83 	if (iy == 0)			/* && ix >= 0x7f800000 */
     84 		return (CMPLXF(x * x, copysignf(0, x) * y));
     85 
     86 	if (ix < 0x7f800000)		/* && iy >= 0x7f800000 */
     87 		return (CMPLXF(y - y, x * (y - y)));
     88 
     89 	if (ix == 0x7f800000) {
     90 		if (iy >= 0x7f800000)
     91 			return (CMPLXF(INFINITY, x * (y - y)));
     92 		return (CMPLXF(INFINITY * cosf(y), x * sinf(y)));
     93 	}
     94 
     95 	return (CMPLXF(((long double)x * x) * (y - y),
     96 	    ((long double)x + x) * (y - y)));
     97 }
     98 
     99 float complex
    100 ccosf(float complex z)
    101 {
    102 
    103 	return (ccoshf(CMPLXF(-cimagf(z), crealf(z))));
    104 }
    105