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/* ef_cosh.c -- float version of e_cosh.c.

 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.

 */

/*

 * ====================================================

 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.

 *

 * Developed at SunPro, a Sun Microsystems, Inc. business.

 * Permission to use, copy, modify, and distribute this

 * software is freely granted, provided that this notice

 * is preserved.

 * ====================================================

 */

#include "fdlibm.h"

#ifdef __v810__

#define const

#endif

#ifdef __STDC__

static const float one = 1.0, half=0.5, huge = 1.0e30;

#else

static float one = 1.0, half=0.5, huge = 1.0e30;

#endif

#ifdef __STDC__

        float __ieee754_coshf(float x)

#else

        float __ieee754_coshf(x)

        float x;

#endif

{

        float t,w;

        __int32_t ix;

        GET_FLOAT_WORD(ix,x);

        ix &= 0x7fffffff;

    /* x is INF or NaN */

        if(ix>=0x7f800000) return x*x;

    /* |x| in [0,0.5*ln2], return 1+expm1(|x|)^2/(2*exp(|x|)) */

        if(ix<0x3eb17218) {

            t = expm1f(fabsf(x));

            w = one+t;

            if (ix<0x24000000) return w;        /* cosh(tiny) = 1 */

            return one+(t*t)/(w+w);

        }

    /* |x| in [0.5*ln2,22], return (exp(|x|)+1/exp(|x|)/2; */

        if (ix < 0x41b00000) {

                t = __ieee754_expf(fabsf(x));

                return half*t+half/t;

        }

    /* |x| in [22, log(maxdouble)] return half*exp(|x|) */

        if (ix < 0x42b17180)  return half*__ieee754_expf(fabsf(x));

    /* |x| in [log(maxdouble), overflowthresold] */

        if (ix<=0x42b2d4fc) {

            w = __ieee754_expf(half*fabsf(x));

            t = half*w;

            return t*w;

        }

    /* |x| > overflowthresold, cosh(x) overflow */

        return huge*huge;

}