sysdeps/ieee754/flt-32/e_sinhf.c

   1 /* e_sinhf.c -- float version of e_sinh.c.
   2  */
   3
   4 /*
   5  * ====================================================
   6  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
   7  *
   8  * Developed at SunPro, a Sun Microsystems, Inc. business.
   9  * Permission to use, copy, modify, and distribute this
  10  * software is freely granted, provided that this notice
  11  * is preserved.
  12  * ====================================================
  13  */
  14
  15 #include <float.h>
  16 #include <math.h>
  17 #include <math-narrow-eval.h>
  18 #include <math_private.h>
  19 #include <math-underflow.h>
  20 #include <libm-alias-finite.h>
  21
  22 static const float one = 1.0, shuge = 1.0e37;
  23
  24 float
  25 __ieee754_sinhf(float x)
  26 {
  27         float t,w,h;
  28         int32_t ix,jx;
  29
  30         GET_FLOAT_WORD(jx,x);
  31         ix = jx&0x7fffffff;
  32
  33     /* x is INF or NaN */
  34         if(__builtin_expect(ix>=0x7f800000, 0)) return x+x;
  35
  36         h = 0.5;
  37         if (jx<0) h = -h;
  38     /* |x| in [0,22], return sign(x)*0.5*(E+E/(E+1))) */
  39         if (ix < 0x41b00000) {          /* |x|<22 */
  40             if (__builtin_expect(ix<0x31800000, 0)) {   /* |x|<2**-28 */
  41                 math_check_force_underflow (x);
  42                 if(shuge+x>one) return x;/* sinh(tiny) = tiny with inexact */
  43             }
  44             t = __expm1f(fabsf(x));
  45             if(ix<0x3f800000) return h*((float)2.0*t-t*t/(t+one));
  46             return h*(t+t/(t+one));
  47         }
  48
  49     /* |x| in [22, log(maxdouble)] return 0.5*exp(|x|) */
  50         if (ix < 0x42b17180)  return h*__ieee754_expf(fabsf(x));
  51
  52     /* |x| in [log(maxdouble), overflowthresold] */
  53         if (ix<=0x42b2d4fc) {
  54             w = __ieee754_expf((float)0.5*fabsf(x));
  55             t = h*w;
  56             return t*w;
  57         }
  58
  59     /* |x| > overflowthresold, sinh(x) overflow */
  60         return math_narrow_eval (x*shuge);
  61 }
  62 libm_alias_finite (__ieee754_sinhf, __sinhf)