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/* @(#)w_asin.c 5.1 93/09/24 */

/*

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

 * 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.

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

 *

 */

/*

FUNCTION

        <<asin>>, <<asinf>>---arc sine

INDEX

   asin

INDEX

   asinf

ANSI_SYNOPSIS

        #include <math.h>

        double asin(double <[x]>);

        float asinf(float <[x]>);

TRAD_SYNOPSIS

        #include <math.h>

        double asin(<[x]>)

        double <[x]>;

        float asinf(<[x]>)

        float <[x]>;

DESCRIPTION

<<asin>> computes the inverse sine (arc sine) of the argument <[x]>.

Arguments to <<asin>> must be in the range @minus{}1 to 1.

<<asinf>> is identical to <<asin>>, other than taking and

returning floats.

You can modify error handling for these routines using <<matherr>>.

RETURNS

@ifinfo

<<asin>> returns values in radians, in the range of -pi/2 to pi/2.

@end ifinfo

@tex

<<asin>> returns values in radians, in the range of $-\pi/2$ to $\pi/2$.

@end tex

If <[x]> is not in the range @minus{}1 to 1, <<asin>> and <<asinf>>

return NaN (not a number), set the global variable <<errno>> to

<<EDOM>>, and issue a <<DOMAIN error>> message.

You can change this error treatment using <<matherr>>.

QUICKREF ANSI SVID POSIX RENTRANT

 asin    y,y,y,m

 asinf   n,n,n,m

MATHREF

 asin,  -1<=arg<=1, asin(arg),,,

 asin,  NAN,  arg,EDOM, DOMAIN

MATHREF

 asinf,  -1<=arg<=1, asin(arg),,,

 asinf,  NAN,  arg,EDOM, DOMAIN

*/

/*

 * wrapper asin(x)

 */

#include "fdlibm.h"

#include <errno.h>

#ifndef _DOUBLE_IS_32BITS

#ifdef __STDC__

        double asin(double x)           /* wrapper asin */

#else

        double asin(x)                  /* wrapper asin */

        double x;

#endif

{

#ifdef _IEEE_LIBM

        return __ieee754_asin(x);

#else

        double z;

        struct exception exc;

        z = __ieee754_asin(x);

        if(_LIB_VERSION == _IEEE_ || isnan(x)) return z;

        if(fabs(x)>1.0) {

            /* asin(|x|>1) */

            exc.type = DOMAIN;

            exc.name = "asin";

            exc.err = 0;

            exc.arg1 = exc.arg2 = x;

            exc.retval = 0.0;

            if(_LIB_VERSION == _POSIX_)

              errno = EDOM;

            else if (!matherr(&exc)) {

              errno = EDOM;

            }

            if (exc.err != 0)

              errno = exc.err;

            return exc.retval;

        } else

            return z;

#endif

}

#endif /* defined(_DOUBLE_IS_32BITS) */