sysdeps/ieee754/flt-32/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 <float.h>
  17 #include <math.h>
  18 #include <math_private.h>
  19
  20 static const float one = 1.0, shuge = 1.0e37;
  21
  22 float
  23 __ieee754_sinhf(float x)
  24 {
  25         float t,w,h;
  26         int32_t ix,jx;
  27
  28         GET_FLOAT_WORD(jx,x);
  29         ix = jx&0x7fffffff;
  30
  31     /* x is INF or NaN */
  32         if(__builtin_expect(ix>=0x7f800000, 0)) return x+x;
  33
  34         h = 0.5;
  35         if (jx<0) h = -h;
  36     /* |x| in [0,22], return sign(x)*0.5*(E+E/(E+1))) */
  37         if (ix < 0x41b00000) {          /* |x|<22 */
  38             if (__builtin_expect(ix<0x31800000, 0)) {   /* |x|<2**-28 */
  39                 math_check_force_underflow (x);
  40                 if(shuge+x>one) return x;/* sinh(tiny) = tiny with inexact */
  41             }
  42             t = __expm1f(fabsf(x));
  43             if(ix<0x3f800000) return h*((float)2.0*t-t*t/(t+one));
  44             return h*(t+t/(t+one));
  45         }
  46
  47     /* |x| in [22, log(maxdouble)] return 0.5*exp(|x|) */
  48         if (ix < 0x42b17180)  return h*__ieee754_expf(fabsf(x));
  49
  50     /* |x| in [log(maxdouble), overflowthresold] */
  51         if (ix<=0x42b2d4fc) {
  52             w = __ieee754_expf((float)0.5*fabsf(x));
  53             t = h*w;
  54             return t*w;
  55         }
  56
  57     /* |x| > overflowthresold, sinh(x) overflow */
  58         return math_narrow_eval (x*shuge);
  59 }
  60 strong_alias (__ieee754_sinhf, __sinhf_finite)