compiler/stdc/math/s_ctanhf.c

   1 /*-
   2  * Copyright (c) 2011 David Schultz
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice unmodified, this list of conditions, and the following
  10  *    disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  */
  26
  27 /*
  28  * Hyperbolic tangent of a complex argument z.  See s_ctanh.c for details.
  29  */
  30
  31 //__FBSDID("$FreeBSD: src/lib/msun/src/s_ctanhf.c,v 1.2 2011/10/21 06:30:16 das Exp $");
  32
  33 #include <complex.h>
  34 #include "math.h"
  35
  36 #include "math_private.h"
  37
  38 float complex
  39 ctanhf(float complex z)
  40 {
  41         float x, y;
  42         float t, beta, s, rho, denom;
  43         uint32_t hx, ix;
  44
  45         x = crealf(z);
  46         y = cimagf(z);
  47
  48         GET_FLOAT_WORD(hx, x);
  49         ix = hx & 0x7fffffff;
  50
  51         if (ix >= 0x7f800000) {
  52                 if (ix & 0x7fffff)
  53                         return (CMPLXF((x + 0) * (y + 0),
  54                             y == 0 ? y : (x + 0) * (y + 0)));
  55                 SET_FLOAT_WORD(x, hx - 0x40000000);
  56                 return (CMPLXF(x,
  57                     copysignf(0, isinf(y) ? y : sinf(y) * cosf(y))));
  58         }
  59
  60         if (!isfinite(y))
  61                 return (CMPLXF(y - y, y - y));
  62
  63         if (ix >= 0x41300000) { /* |x| >= 11 */
  64                 float exp_mx = expf(-fabsf(x));
  65                 return (CMPLXF(copysignf(1, x),
  66                     4 * sinf(y) * cosf(y) * exp_mx * exp_mx));
  67         }
  68
  69         t = tanf(y);
  70         beta = 1.0 + t * t;
  71         s = sinhf(x);
  72         rho = sqrtf(1 + s * s);
  73         denom = 1 + beta * s * s;
  74         return (CMPLXF((beta * rho * s) / denom, t / denom));
  75 }