xref: /freebsd/sys/i386/include/ieeefp.h (revision 2ff63af9b88c7413b7d71715b5532625752a248e)
1 /*-
2  * SPDX-License-Identifier: BSD-4-Clause
3  *
4  * Copyright (c) 2003 Peter Wemm.
5  * Copyright (c) 1990 Andrew Moore, Talke Studio
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. All advertising materials mentioning features or use of this software
17  *    must display the following acknowledgement:
18  *	This product includes software developed by the University of
19  *	California, Berkeley and its contributors.
20  * 4. Neither the name of the University nor the names of its contributors
21  *    may be used to endorse or promote products derived from this software
22  *    without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  *
36  * 	from: @(#) ieeefp.h 	1.0 (Berkeley) 9/23/93
37  */
38 
39 #ifndef _MACHINE_IEEEFP_H_
40 #define _MACHINE_IEEEFP_H_
41 
42 /* Deprecated historical FPU control interface */
43 
44 #include <x86/x86_ieeefp.h>
45 
46 static __inline fp_rnd_t
47 fpgetround(void)
48 {
49 	unsigned short _cw;
50 
51 	__fnstcw(&_cw);
52 	return ((fp_rnd_t)((_cw & FP_RND_FLD) >> FP_RND_OFF));
53 }
54 
55 static __inline fp_rnd_t
56 fpsetround(fp_rnd_t _m)
57 {
58 	fp_rnd_t _p;
59 	unsigned short _cw, _newcw;
60 
61 	__fnstcw(&_cw);
62 	_p = (fp_rnd_t)((_cw & FP_RND_FLD) >> FP_RND_OFF);
63 	_newcw = _cw & ~FP_RND_FLD;
64 	_newcw |= (_m << FP_RND_OFF) & FP_RND_FLD;
65 	__fnldcw(_cw, _newcw);
66 	return (_p);
67 }
68 
69 static __inline fp_prec_t
70 fpgetprec(void)
71 {
72 	unsigned short _cw;
73 
74 	__fnstcw(&_cw);
75 	return ((fp_prec_t)((_cw & FP_PRC_FLD) >> FP_PRC_OFF));
76 }
77 
78 static __inline fp_prec_t
79 fpsetprec(fp_prec_t _m)
80 {
81 	fp_prec_t _p;
82 	unsigned short _cw, _newcw;
83 
84 	__fnstcw(&_cw);
85 	_p = (fp_prec_t)((_cw & FP_PRC_FLD) >> FP_PRC_OFF);
86 	_newcw = _cw & ~FP_PRC_FLD;
87 	_newcw |= (_m << FP_PRC_OFF) & FP_PRC_FLD;
88 	__fnldcw(_cw, _newcw);
89 	return (_p);
90 }
91 
92 /*
93  * Get or set the exception mask.
94  * Note that the x87 mask bits are inverted by the API -- a mask bit of 1
95  * means disable for x87 and SSE, but for fp*mask() it means enable.
96  */
97 
98 static __inline fp_except_t
99 fpgetmask(void)
100 {
101 	unsigned short _cw;
102 
103 	__fnstcw(&_cw);
104 	return ((~_cw & FP_MSKS_FLD) >> FP_MSKS_OFF);
105 }
106 
107 static __inline fp_except_t
108 fpsetmask(fp_except_t _m)
109 {
110 	fp_except_t _p;
111 	unsigned short _cw, _newcw;
112 
113 	__fnstcw(&_cw);
114 	_p = (~_cw & FP_MSKS_FLD) >> FP_MSKS_OFF;
115 	_newcw = _cw & ~FP_MSKS_FLD;
116 	_newcw |= (~_m << FP_MSKS_OFF) & FP_MSKS_FLD;
117 	__fnldcw(_cw, _newcw);
118 	return (_p);
119 }
120 
121 static __inline fp_except_t
122 fpgetsticky(void)
123 {
124 	unsigned _ex;
125 	unsigned short _sw;
126 
127 	__fnstsw(&_sw);
128 	_ex = (_sw & FP_STKY_FLD) >> FP_STKY_OFF;
129 	return ((fp_except_t)_ex);
130 }
131 
132 static __inline fp_except_t
133 fpresetsticky(fp_except_t _m)
134 {
135 	struct {
136 		unsigned _cw;
137 		unsigned _sw;
138 		unsigned _other[5];
139 	} _env;
140 	fp_except_t _p;
141 
142 	_m &= FP_STKY_FLD >> FP_STKY_OFF;
143 	_p = fpgetsticky();
144 	if ((_p & ~_m) == _p)
145 		return (_p);
146 	if ((_p & ~_m) == 0) {
147 		__fnclex();
148 		return (_p);
149 	}
150 	__fnstenv(&_env);
151 	_env._sw &= ~_m;
152 	__fldenv(&_env);
153 	return (_p);
154 }
155 
156 #endif /* !_MACHINE_IEEEFP_H_ */
157