s_isnan.cpp

来自「这是整套横扫千军3D版游戏的源码」· C++ 代码 · 共 48 行

/* See the import.pl script for potential modifications */
/* @(#)s_isnan.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.
 * ====================================================
 */

#if defined(LIBM_SCCS) && !defined(lint)
static char rcsid[] = "$NetBSD: s_isnan.c,v 1.8 1995/05/10 20:47:36 jtc Exp $";
#endif

/*
 * isnan(x) returns 1 is x is nan, else 0;
 * no branching!
 */

#include "math.h"
#include "math_private.h"

namespace streflop_libm {
#ifdef __STDC__
	int __isnan(Double x)
#else
	int __isnan(x)
	Double x;
#endif
{
	int32_t hx,lx;
	EXTRACT_WORDS(hx,lx,x);
	hx &= 0x7fffffff;
	hx |= (u_int32_t)(lx|(-lx))>>31;
	hx = 0x7ff00000 - hx;
	return (int)(((u_int32_t)hx)>>31);
}
hidden_def (__isnan)
weak_alias (__isnan, isnan)
#ifdef NO_LONG_DOUBLE
strong_alias (__isnan, __isnanl)
weak_alias (__isnan, isnanl)
#endif
}