get_hw_float.c

来自「基于组件方式开发操作系统的OSKIT源代码」· C语言 代码 · 共 51 行

/*-
 * Copyright (c) 1997 Bruce D. Evans
 * 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.
 *
 *	$Id: get_hw_float.c,v 1.2 1997/02/22 15:10:42 peter Exp $
 */

#include <sys/types.h>
#include <sys/sysctl.h>

int	__get_hw_float __P((void));

static int	hw_float = -1;

int
__get_hw_float()
{
	size_t len;
	int mib[2];

	if (hw_float == -1) {
		len = sizeof(hw_float);
		mib[0] = CTL_HW;
		mib[1] = HW_FLOATINGPT;
		if (__sysctl(mib, 2, &hw_float, &len, (void *)0, 0) == -1)
			hw_float = 0;	/* shouldn't happen; assume the worst */
	}
	return (hw_float);
}