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)