w_scalb.c

来自「This is a resource based on j2me embedde」· C语言 代码 · 共 70 行

/*
 * @(#)w_scalb.c	1.11 06/10/10
 *
 * Copyright  1990-2008 Sun Microsystems, Inc. All Rights Reserved.  
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER  
 *   
 * This program is free software; you can redistribute it and/or  
 * modify it under the terms of the GNU General Public License version  
 * 2 only, as published by the Free Software Foundation.   
 *   
 * This program is distributed in the hope that it will be useful, but  
 * WITHOUT ANY WARRANTY; without even the implied warranty of  
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU  
 * General Public License version 2 for more details (a copy is  
 * included at /legal/license.txt).   
 *   
 * You should have received a copy of the GNU General Public License  
 * version 2 along with this work; if not, write to the Free Software  
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  
 * 02110-1301 USA   
 *   
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa  
 * Clara, CA 95054 or visit www.sun.com if you need additional  
 * information or have any questions. 
 *
 */

/*
 * wrapper scalb(double x, double fn) is provide for
 * passing various standard test suite. One
 * should use scalbn() instead.
 */

#include "javavm/include/porting/ansi/errno.h"
#include "fdlibm.h"

#ifdef __STDC__
#ifdef _SCALB_INT
	double scalb(double x, int fn)		/* wrapper scalb */
#else
	double scalb(double x, double fn)	/* wrapper scalb */
#endif
#else
	double scalb(x,fn)			/* wrapper scalb */
#ifdef _SCALB_INT
	double x; int fn;
#else
	double x,fn;
#endif
#endif
{
#ifdef _IEEE_LIBM
	return __ieee754_scalb(x,fn);
#else
	double z;
	z = __ieee754_scalb(x,fn);
	if(_LIB_VERSION == _IEEE_) return z;
	if(!(finite(z)||isnan(z))&&finite(x)) {
	    return __kernel_standard(x,(double)fn,32); /* scalb overflow */
	}
	if(z==0.0&&z!=x) {
	    return __kernel_standard(x,(double)fn,33); /* scalb underflow */
	}
#ifndef _SCALB_INT
	if(!finite(fn)) errno = ERANGE;
#endif
	return z;
#endif
}