contrib/openbsd_libm/src/e_sinhf.c

   1 /* e_sinhf.c -- float version of e_sinh.c.
   2  * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
   3  */
   4
   5 /*
   6  * ====================================================
   7  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
   8  *
   9  * Developed at SunPro, a Sun Microsystems, Inc. business.
  10  * Permission to use, copy, modify, and distribute this
  11  * software is freely granted, provided that this notice
  12  * is preserved.
  13  * ====================================================
  14  */
  15
  16 #include "math.h"
  17 #include "math_private.h"
  18
  19 static const float one = 1.0, shuge = 1.0e37;
  20
  21 float
  22 sinhf(float x)
  23 {
  24         float t,w,h;
  25         int32_t ix,jx;
  26
  27         GET_FLOAT_WORD(jx,x);
  28         ix = jx&0x7fffffff;
  29
  30     /* x is INF or NaN */
  31         if(ix>=0x7f800000) return x+x;
  32
  33         h = 0.5;
  34         if (jx<0) h = -h;
  35     /* |x| in [0,22], return sign(x)*0.5*(E+E/(E+1))) */
  36         if (ix < 0x41b00000) {          /* |x|<22 */
  37             if (ix<0x31800000)          /* |x|<2**-28 */
  38                 if(shuge+x>one) return x;/* sinh(tiny) = tiny with inexact */
  39             t = expm1f(fabsf(x));
  40             if(ix<0x3f800000) return h*((float)2.0*t-t*t/(t+one));
  41             return h*(t+t/(t+one));
  42         }
  43
  44     /* |x| in [22, log(maxdouble)] return 0.5*exp(|x|) */
  45         if (ix < 0x42b17180)  return h*expf(fabsf(x));
  46
  47     /* |x| in [log(maxdouble), overflowthresold] */
  48         if (ix<=0x42b2d4fc) {
  49             w = expf((float)0.5*fabsf(x));
  50             t = h*w;
  51             return t*w;
  52         }
  53
  54     /* |x| > overflowthresold, sinh(x) overflow */
  55         return x*shuge;
  56 }