test_float

<B>Digital的Unix操作系统VAX 4.2源码</B>

#ifndef lint
static char	"sccs = @(#)Test_float	4.1	(ULTRIX)	7/3/90";
#endif lint

/************************************************************************
 *									*
 *			Copyright (c) 1983 by				*
 *		Digital Equipment Corporation, Maynard, MA		*
 *			All rights reserved.				*
 *									*
 *   This software is furnished under a license and may be used and	*
 *   copied  only  in accordance with the terms of such license and	*
 *   with the  inclusion  of  the  above  copyright  notice.   This	*
 *   software  or  any  other copies thereof may not be provided or	*
 *   otherwise made available to any other person.  No title to and	*
 *   ownership of the software is hereby transferred.			*
 *									*
 *   This software is  derived  from  software  received  from  the	*
 *   University    of   California,   Berkeley,   and   from   Bell	*
 *   Laboratories.  Use, duplication, or disclosure is  subject  to	*
 *   restrictions  under  license  agreements  with  University  of	*
 *   California and with AT&T.						*
 *									*
 *   The information in this software is subject to change  without	*
 *   notice  and should not be construed as a commitment by Digital	*
 *   Equipment Corporation.						*
 *									*
 *   Digital assumes no responsibility for the use  or  reliability	*
 *   of its software on equipment which is not supplied by Digital.	*
 *									*
 ************************************************************************/

/************************************************************************
*
*			Modification History
*
*	David Metsky		13-Jan-86
*
* 001	Added from BSD 4.3 version as part of upgrade.
*
*************************************************************************/

#!	/bin/csh -f 
#
#	this tests if C rounds the return value to single precision in
#	functions of type float. (see sec. 9.10 of C ref. manual).
#
cat << 'EOT' >! /tmp/test_fltc.c
float temp;

float f1_(arg1,arg2)
float *arg1, *arg2;
{
	/* force float by storing in global */
	temp =  *arg1 / *arg2;
	return temp;
}

float f2_(arg1,arg2)
float *arg1, *arg2;
{
	/* should round since function is type float */
	return  *arg1 / *arg2;
}


float f3_(arg1,arg2)
float *arg1, *arg2;
{
	/* use a cast to try to force rounding */
	return ((float) (*arg1 / *arg2));
}

'EOT'
cat << 'EOT' >! /tmp/test_fltf.f
	integer f2ok, f3ok
	data f2ok/0/, f3ok/0/

	do 20 i = 1,10
	do 10 j = 1,10
	x = 0.1d0*i
	y = 0.1d0*j
	temp = f1(x,y)
	if( f2(x,y).eq.temp) f2ok = f2ok + 1
	if( f3(x,y).eq.temp) f3ok = f3ok + 1
10	continue
20	continue
	print *, "out of 100 tries, f2 was ok", f2ok, "times"
	print *, "out of 100 tries, f3 was ok", f3ok, "times"
	end
'EOT'
pushd /tmp
f77 test_fltc.c test_fltf.f -o test_flt
test_flt