freebsd-src/lib/libc/gen/isnan.c
Dimitry Andric 34a4971299 Add an explanatory comment to lib/libc/gen/isnan.c about the fix to make
static linking with libc and libm work.

Requested by:	jilles
MFC after:	1 week
X-MFC-With:	242879
2012-11-11 13:28:04 +00:00

65 lines
2.1 KiB
C

/*-
* Copyright (c) 2004 David Schultz <das@FreeBSD.ORG>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#include <math.h>
#include "fpmath.h"
/*
* XXX These routines belong in libm, but they must remain in libc for
* binary compat until we can bump libm's major version number.
*
* Note this only applies to the dynamic versions of libm and libc, so
* for the static and profiled versions we stub out the definitions.
* Otherwise you cannot link statically to libm and libc at the same
* time, when calling both functions.
*/
#ifdef PIC
__weak_reference(__isnan, isnan);
__weak_reference(__isnanf, isnanf);
int
__isnan(double d)
{
union IEEEd2bits u;
u.d = d;
return (u.bits.exp == 2047 && (u.bits.manl != 0 || u.bits.manh != 0));
}
int
__isnanf(float f)
{
union IEEEf2bits u;
u.f = f;
return (u.bits.exp == 255 && u.bits.man != 0);
}
#endif /* PIC */