text: 
  /* @(#)e_sinh.c 1.3 95/01/18 */
  /*
   * ====================================================
   * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
   *
   * Developed at SunSoft, a Sun Microsystems, Inc. business.
   * Permission to use, copy, modify, and distribute this
   * software is freely granted, provided that this notice 
   * is preserved.
   * ====================================================
   */
  
  /* __ieee754_sinh(x)
   * Method : 
   * mathematically sinh(x) if defined to be (exp(x)-exp(-x))/2
   *	1. Replace x by |x| (sinh(-x) = -sinh(x)). 
   *	2. 
   *		                                    E + E/(E+1)
   *	    0        <= x <= 22     :  sinh(x) := --------------, E=expm1(x)
   *			       			        2
   *
   *	    22       <= x <= lnovft :  sinh(x) := exp(x)/2 
   *	    lnovft   <= x <= ln2ovft:  sinh(x) := exp(x/2)/2 * exp(x/2)
   *	    ln2ovft  <  x	    :  sinh(x) := x*shuge (overflow)
   *
   * Special cases:
   *	sinh(x) is |x| if x is +INF, -INF, or NaN.
   *	only sinh(0)=0 is exact for finite x.
   */
  
  #include "fdlibm.h"
  
  #ifndef _DOUBLE_IS_32BITS  
  
  #ifdef __STDC__
  static const double one = 1.0, shuge = 1.0e307;
  #else
  static double one = 1.0, shuge = 1.0e307;
  #endif
  
  #ifdef __STDC__
  	double __ieee754_sinh(double x)
  #else
  	double __ieee754_sinh(x)
  	double x;
  #endif
  {	
  	double t,w,h;
  	int32_t ix,jx;
  	uint32_t lx;
  
      /* High word of |x|. */
  	GET_HIGH_WORD(jx,x);
  	ix = jx&0x7fffffff;
  
      /* x is INF or NaN */
  	if(ix>=0x7ff00000) return x+x;	
  
  	h = 0.5;
  	if (jx<0) h = -h;
      /* |x| in [0,22], return sign(x)*0.5*(E+E/(E+1))) */
  	if (ix < 0x40360000) {		/* |x|<22 */
  	    if (ix<0x3e300000) 		/* |x|<2**-28 */
  		if(shuge+x>one) return x;/* sinh(tiny) = tiny with inexact */
  	    t = expm1(fabs(x));
  	    if(ix<0x3ff00000) return h*(2.0*t-t*t/(t+one));
  	    return h*(t+t/(t+one));
  	}
  
      /* |x| in [22, log(maxdouble)] return 0.5*exp(|x|) */
  	if (ix < 0x40862E42)  return h*__ieee754_exp(fabs(x));
  
      /* |x| in [log(maxdouble), overflowthresold] */
  	lx = *( (((*(uint32_t*)&one)>>29)) + (uint32_t*)&x);
  	if (ix<0x408633CE || (ix==0x408633ce)&&(lx<=(uint32_t)0x8fb9f87d)) {
  	    w = __ieee754_exp(0.5*fabs(x));
  	    t = h*w;
  	    return t*w;
  	}
  
      /* |x| > overflowthresold, sinh(x) overflow */
  	return x*shuge;
  }
  #endif /* defined(_DOUBLE_IS_32BITS) */
  