floatingpoint.h revision 719 
1/*-
2 * Copyright (c) 1993 Andrew Moore, Talke Studio
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 *	from: @(#) floatingpoint.h	1.0 (Berkeley) 9/23/93
34 *	$Id: floatingpoint.h,v 1.3 1993/10/16 14:39:18 rgrimes Exp $
35 */
36
37/*
38 *	IEEE floating point structure and function definitions
39 */
40
41#ifndef _FLOATINGPOINT_H_
42#define _FLOATINGPOINT_H_
43
44#include <sys/cdefs.h>
45#include <sys/ieeefp.h>
46
47#ifdef __GNUC__
48
49#ifdef __i386__
50
51#define fnstcw(addr)	__asm("fnstcw %0" : "=m" (*addr) : "0" (*addr))
52#define fnstsw(addr)	__asm("fnstsw %0" : "=m" (*addr) : "0" (*addr))
53#define fnstenv(addr)	__asm("fnstenv %0" : "=m" (*addr) : "0" (*addr))
54#define fldenv(addr)	__asm("fldenv %0" : : "m" (*addr))
55
56
57/*
58 * return the contents of a FP register
59 */
60static __inline__ int
61__fpgetreg(int _reg)
62{
63	unsigned short _mem;
64
65	switch(_reg) {
66	default:
67		fnstcw(&_mem);
68		break;
69	case FP_STKY_REG:
70		fnstsw(&_mem);
71		break;
72	}
73	return _mem;
74}
75
76/*
77 * set a FP mode; return previous mode
78 */
79static __inline__ int
80__fpsetreg(int _m, int _reg, int _fld, int _off)
81{
82	unsigned _env[7];
83	unsigned _p;
84
85	fnstenv(_env);
86	_p =  (_env[_reg] & _fld) >> _off;
87	_env[_reg] = (_env[_reg] & ~_fld) | (_m << _off & _fld);
88	fldenv(_env);
89	return _p;
90}
91
92#endif /* __i386__ */
93
94#endif /* __GNUC__ */
95
96/*
97 * SysV/386 FP control interface
98 */
99#define fpgetround()	((__fpgetreg(FP_RND_REG) & FP_RND_FLD) >> FP_RND_OFF)
100#define fpsetround(m)	__fpsetreg((m), FP_RND_REG, FP_RND_FLD, FP_RND_OFF)
101#define fpgetprec()	((__fpgetreg(FP_PRC_REG) & FP_PRC_FLD) >> FP_PRC_OFF)
102#define fpsetprec(m)	__fpsetreg((m), FP_PRC_REG, FP_PRC_FLD, FP_PRC_OFF)
103#define fpgetmask()	((~__fpgetreg(FP_MSKS_REG) & FP_MSKS_FLD) >> FP_MSKS_OFF)
104#define fpsetmask(m)	__fpsetreg(~(m), FP_MSKS_REG, FP_MSKS_FLD, FP_MSKS_OFF)
105#define fpgetsticky()	((__fpgetreg(FP_STKY_REG) & FP_STKY_FLD) >> FP_STKY_OFF)
106#define fpresetsticky(m)	__fpsetreg(0, FP_STKY_REG, (m), FP_STKY_OFF)
107#define fpsetsticky(m)	fpresetsticky(m)
108
109#endif /* !_FLOATINGPOINT_H_ */
110