newlib-cygwin/newlib/libm/math/w_sqrt.c

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2000-02-18 03:39:52 +08:00
/* @(#)w_sqrt.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
<<sqrt>>, <<sqrtf>>---positive square root
INDEX
sqrt
INDEX
sqrtf
ANSI_SYNOPSIS
#include <math.h>
double sqrt(double <[x]>);
float sqrtf(float <[x]>);
TRAD_SYNOPSIS
#include <math.h>
double sqrt(<[x]>);
float sqrtf(<[x]>);
DESCRIPTION
<<sqrt>> computes the positive square root of the argument.
You can modify error handling for this function with
<<matherr>>.
RETURNS
On success, the square root is returned. If <[x]> is real and
positive, then the result is positive. If <[x]> is real and
negative, the global value <<errno>> is set to <<EDOM>> (domain error).
PORTABILITY
<<sqrt>> is ANSI C. <<sqrtf>> is an extension.
*/
/*
* wrapper sqrt(x)
*/
#include "fdlibm.h"
#include <errno.h>
#ifndef _DOUBLE_IS_32BITS
#ifdef __STDC__
double sqrt(double x) /* wrapper sqrt */
#else
double sqrt(x) /* wrapper sqrt */
double x;
#endif
{
#ifdef _IEEE_LIBM
return __ieee754_sqrt(x);
#else
struct exception exc;
double z;
z = __ieee754_sqrt(x);
if(_LIB_VERSION == _IEEE_ || isnan(x)) return z;
if(x<0.0) {
exc.type = DOMAIN;
exc.name = "sqrt";
exc.err = 0;
exc.arg1 = exc.arg2 = x;
if (_LIB_VERSION == _SVID_)
exc.retval = 0.0;
else
exc.retval = 0.0/0.0;
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) */