freebsd-nq/lib/msun/src/e_scalb.c
David Schultz 7a773faadc Fix a problem where libm compiled under 5.X would depend on features
that are only in libc.so.5.  This broke some 4.X applications linked
to libm and run under 5.X.

Background:
In C99, isinf() and isnan() cannot be implemented as regular
functions.  We use macros that call libc functions in 5.X, but for
libm-internal use, we need to use the old versions until the next
time libm's major version number is bumped.

Submitted by:	bde
Reported by:	imp, kris
2003-10-27 01:28:07 +00:00

51 lines
1.2 KiB
C

/* @(#)e_scalb.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.
* ====================================================
*/
#ifndef lint
static char rcsid[] = "$FreeBSD$";
#endif
/*
* __ieee754_scalb(x, fn) is provide for
* passing various standard test suite. One
* should use scalbn() instead.
*/
#include "math.h"
#include "math_private.h"
/* XXX lost declaration of this and isinf() in math.h but still have funcs. */
int (isnan)(float x);
#ifdef _SCALB_INT
double
__ieee754_scalb(double x, int fn)
#else
double
__ieee754_scalb(double x, double fn)
#endif
{
#ifdef _SCALB_INT
return scalbn(x,fn);
#else
if ((isnan)(x)||(isnan)(fn)) return x*fn;
if (!finite(fn)) {
if(fn>0.0) return x*fn;
else return x/(-fn);
}
if (rint(fn)!=fn) return (fn-fn)/(fn-fn);
if ( fn > 65000.0) return scalbn(x, 65000);
if (-fn > 65000.0) return scalbn(x,-65000);
return scalbn(x,(int)fn);
#endif
}