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      1 /* e_sinhf.c -- float version of e_sinh.c.
      2  * Conversion to float by Ian Lance Taylor, Cygnus Support, ian (at) 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 <sys/cdefs.h>
     17 #if defined(LIBM_SCCS) && !defined(lint)
     18 __RCSID("$NetBSD: e_sinhf.c,v 1.7 2002/05/26 22:01:52 wiz Exp $");
     19 #endif
     20 
     21 #include "math.h"
     22 #include "math_private.h"
     23 
     24 static const float one = 1.0, shuge = 1.0e37;
     25 
     26 float
     27 __ieee754_sinhf(float x)
     28 {
     29 	float t,w,h;
     30 	int32_t ix,jx;
     31 
     32 	GET_FLOAT_WORD(jx,x);
     33 	ix = jx&0x7fffffff;
     34 
     35     /* x is INF or NaN */
     36 	if(ix>=0x7f800000) return x+x;
     37 
     38 	h = 0.5;
     39 	if (jx<0) h = -h;
     40     /* |x| in [0,22], return sign(x)*0.5*(E+E/(E+1))) */
     41 	if (ix < 0x41b00000) {		/* |x|<22 */
     42 	    if (ix<0x31800000) 		/* |x|<2**-28 */
     43 		if(shuge+x>one) return x;/* sinh(tiny) = tiny with inexact */
     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 x*shuge;
     61 }
     62