compiler/stdc/math/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 #ifndef lint
  17 static char rcsid[] = "$FreeBSD: src/lib/msun/src/e_sinhf.c,v 1.8 2005/11/13 00:41:46 bde Exp $";
  18 #endif
  19
  20 #include "math.h"
  21 #include "math_private.h"
  22
  23 static const float one = 1.0, shuge = 1.0e37;
  24
  25 float
  26 __ieee754_sinhf(float x)
  27 {
  28         float t,w,h;
  29         int32_t ix,jx;
  30
  31         GET_FLOAT_WORD(jx,x);
  32         ix = jx&0x7fffffff;
  33
  34     /* x is INF or NaN */
  35         if(ix>=0x7f800000) return x+x;
  36
  37         h = 0.5;
  38         if (jx<0) h = -h;
  39     /* |x| in [0,9], return sign(x)*0.5*(E+E/(E+1))) */
  40         if (ix < 0x41100000) {          /* |x|<9 */
  41             if (ix<0x39800000)          /* |x|<2**-12 */
  42                 if(shuge+x>one) return x;/* sinh(tiny) = tiny with inexact */
  43             t = expm1f(fabsf(x));
  44             if(ix<0x3f800000) return h*((float)2.0*t-t*t/(t+one));
  45             return h*(t+t/(t+one));
  46         }
  47
  48     /* |x| in [9, logf(maxfloat)] return 0.5*exp(|x|) */
  49         if (ix < 0x42b17217)  return h*__ieee754_expf(fabsf(x));
  50
  51     /* |x| in [logf(maxfloat), overflowthresold] */
  52         if (ix<=0x42b2d4fc) {
  53             w = __ieee754_expf((float)0.5*fabsf(x));
  54             t = h*w;
  55             return t*w;
  56         }
  57
  58     /* |x| > overflowthresold, sinh(x) overflow */
  59         return x*shuge;
  60 }