compiler/stdc/math/s_ccoshf.c

   1 /*-
   2  * Copyright (c) 2005 Bruce D. Evans and Steven G. Kargl
   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  * Float version of ccosh().  See s_ccosh.c for details.
  29  */
  30
  31 //__FBSDID("$FreeBSD: src/lib/msun/src/s_ccoshf.c,v 1.2 2011/10/21 06:29:32 das Exp $");
  32
  33 #include <complex.h>
  34 #include "math.h"
  35
  36 #include "math_private.h"
  37
  38 static const float huge = 0x1p127;
  39
  40 float complex
  41 ccoshf(float complex z)
  42 {
  43         float x, y, h;
  44         int32_t hx, hy, ix, iy;
  45
  46         x = crealf(z);
  47         y = cimagf(z);
  48
  49         GET_FLOAT_WORD(hx, x);
  50         GET_FLOAT_WORD(hy, y);
  51
  52         ix = 0x7fffffff & hx;
  53         iy = 0x7fffffff & hy;
  54
  55         if (ix < 0x7f800000 && iy < 0x7f800000) {
  56                 if (iy == 0)
  57                         return (CMPLXF(coshf(x), x * y));
  58                 if (ix < 0x41100000)    /* |x| < 9: normal case */
  59                         return (CMPLXF(coshf(x) * cosf(y), sinhf(x) * sinf(y)));
  60
  61                 /* |x| >= 9, so cosh(x) ~= exp(|x|) */
  62                 if (ix < 0x42b17218) {
  63                         /* x < 88.7: expf(|x|) won't overflow */
  64                         h = expf(fabsf(x)) * 0.5F;
  65                         return (CMPLXF(h * cosf(y), copysignf(h, x) * sinf(y)));
  66                 } else if (ix < 0x4340b1e7) {
  67                         /* x < 192.7: scale to avoid overflow */
  68                         z = __ldexp_cexpf(CMPLXF(fabsf(x), y), -1);
  69                         return (CMPLXF(crealf(z), cimagf(z) * copysignf(1, x)));
  70                 } else {
  71                         /* x >= 192.7: the result always overflows */
  72                         h = huge * x;
  73                         return (CMPLXF(h * h * cosf(y), h * sinf(y)));
  74                 }
  75         }
  76
  77         if (ix == 0)                    /* && iy >= 0x7f800000 */
  78                 return (CMPLXF(y - y, x * copysignf(0, y)));
  79
  80         if (iy == 0)                    /* && ix >= 0x7f800000 */
  81                         return (CMPLXF(x * x, copysignf(0, x) * y));
  82
  83         if (ix < 0x7f800000)            /* && iy >= 0x7f800000 */
  84                 return (CMPLXF(y - y, x * (y - y)));
  85
  86         if (ix == 0x7f800000) {
  87                 if (iy >= 0x7f800000)
  88                         return (CMPLXF(INFINITY, x * (y - y)));
  89                 return (CMPLXF(INFINITY * cosf(y), x * sinf(y)));
  90         }
  91
  92         return (CMPLXF((x * x) * (y - y), (x + x) * (y - y)));
  93 }