src/complex/csinhf.c

   1 /* origin: FreeBSD /usr/src/lib/msun/src/s_csinhf.c */
   2 /*-
   3  * Copyright (c) 2005 Bruce D. Evans and Steven G. Kargl
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice unmodified, this list of conditions, and the following
  11  *    disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26  */
  27 /*
  28  * Hyperbolic sine of a complex argument z.  See s_csinh.c for details.
  29  */
  30
  31 #include "complex_impl.h"
  32
  33 static const float huge = 0x1p127;
  34
  35 float complex csinhf(float complex z)
  36 {
  37         float x, y, h;
  38         int32_t hx, hy, ix, iy;
  39
  40         x = crealf(z);
  41         y = cimagf(z);
  42
  43         GET_FLOAT_WORD(hx, x);
  44         GET_FLOAT_WORD(hy, y);
  45
  46         ix = 0x7fffffff & hx;
  47         iy = 0x7fffffff & hy;
  48
  49         if (ix < 0x7f800000 && iy < 0x7f800000) {
  50                 if (iy == 0)
  51                         return CMPLXF(sinhf(x), y);
  52                 if (ix < 0x41100000)    /* small x: normal case */
  53                         return CMPLXF(sinhf(x) * cosf(y), coshf(x) * sinf(y));
  54
  55                 /* |x| >= 9, so cosh(x) ~= exp(|x|) */
  56                 if (ix < 0x42b17218) {
  57                         /* x < 88.7: expf(|x|) won't overflow */
  58                         h = expf(fabsf(x)) * 0.5f;
  59                         return CMPLXF(copysignf(h, x) * cosf(y), h * sinf(y));
  60                 } else if (ix < 0x4340b1e7) {
  61                         /* x < 192.7: scale to avoid overflow */
  62                         z = __ldexp_cexpf(CMPLXF(fabsf(x), y), -1);
  63                         return CMPLXF(crealf(z) * copysignf(1, x), cimagf(z));
  64                 } else {
  65                         /* x >= 192.7: the result always overflows */
  66                         h = huge * x;
  67                         return CMPLXF(h * cosf(y), h * h * sinf(y));
  68                 }
  69         }
  70
  71         if (ix == 0 && iy >= 0x7f800000)
  72                 return CMPLXF(copysignf(0, x * (y - y)), y - y);
  73
  74         if (iy == 0 && ix >= 0x7f800000) {
  75                 if ((hx & 0x7fffff) == 0)
  76                         return CMPLXF(x, y);
  77                 return CMPLXF(x, copysignf(0, y));
  78         }
  79
  80         if (ix < 0x7f800000 && iy >= 0x7f800000)
  81                 return CMPLXF(y - y, x * (y - y));
  82
  83         if (ix >= 0x7f800000 && (hx & 0x7fffff) == 0) {
  84                 if (iy >= 0x7f800000)
  85                         return CMPLXF(x * x, x * (y - y));
  86                 return CMPLXF(x * cosf(y), INFINITY * sinf(y));
  87         }
  88
  89         return CMPLXF((x * x) * (y - y), (x + x) * (y - y));
  90 }