_ftou.c

来自「操作系统SunOS 4.1.3版本的源码」· C语言 代码 · 共 52 行

#ifndef lint
static	char sccsid[] = "@(#)_ftou.c 1.1 92/07/30 SMI";
#endif

/*
 * Copyright (c) 1987 by Sun Microsystems, Inc.
 */

unsigned 
_dtou(d)
	double          d;
{
	/* Convert double to unsigned.     */

	int             id;

	/*
	 * id = d is correct if 0 <= d < 2**31, and good enough if d is NaN
	 * or d < 0 or d >= 2**32.  Otherwise, since the result (int) d of
	 * converting 2**31 <= d < 2**32 is unknown, adjust d before the
	 * conversion. 
	 */

	if (d >= 2147483648.0)
		id = 0x80000000 | (int) (d - 2147483648.0);
	else
		id = (int) d;
	return (unsigned) id;
}

unsigned 
_ftou(dd)
	int          dd;		/* really float */
{
	/* Convert float to unsigned.     */

	int             id;
	double		d = (double) *((float *)(&dd));
	/*
	 * id = d is correct if 0 <= d < 2**31, and good enough if d is NaN
	 * or d < 0 or d >= 2**32.  Otherwise, since the result (int) d of
	 * converting 2**31 <= d < 2**32 is unknown, adjust d before the
	 * conversion. 
	 */

	if (d >= 2147483648.0)
		id = 0x80000000 | (int) (d - 2147483648.0);
	else
		id = (int) d;
	return (unsigned) id;
}