summaryrefslogtreecommitdiffstats
path: root/sys/i386/include/ieeefp.h
blob: c676c4541831dddbec259dd310c9affb0ee9447f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
/*-
 * Copyright (c) 2003 Peter Wemm.
 * Copyright (c) 1990 Andrew Moore, Talke Studio
 * 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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 *
 * 	from: @(#) ieeefp.h 	1.0 (Berkeley) 9/23/93
 * $FreeBSD$
 */

#ifndef _MACHINE_IEEEFP_H_
#define _MACHINE_IEEEFP_H_

/*
 * Deprecated historical FPU control interface
 *
 * IEEE floating point type, constant and function definitions.
 * XXX: FP*FLD and FP*OFF are undocumented pollution.
 */

#ifndef _SYS_CDEFS_H_
#error this file needs sys/cdefs.h as a prerequisite
#endif

/*
 * Rounding modes.
 */
typedef enum {
	FP_RN=0,	/* round to nearest */
	FP_RM,		/* round down towards minus infinity */
	FP_RP,		/* round up towards plus infinity */
	FP_RZ		/* truncate */
} fp_rnd_t;

/*
 * Precision (i.e., rounding precision) modes.
 */
typedef enum {
	FP_PS=0,	/* 24 bit (single-precision) */
	FP_PRS,		/* reserved */
	FP_PD,		/* 53 bit (double-precision) */
	FP_PE		/* 64 bit (extended-precision) */
} fp_prec_t;

#define fp_except_t	int

/*
 * Exception bit masks.
 */
#define FP_X_INV	0x01	/* invalid operation */
#define FP_X_DNML	0x02	/* denormal */
#define FP_X_DZ		0x04	/* zero divide */
#define FP_X_OFL	0x08	/* overflow */
#define FP_X_UFL	0x10	/* underflow */
#define FP_X_IMP	0x20	/* (im)precision */
#define FP_X_STK	0x40	/* stack fault */

/*
 * FPU control word bit-field masks.
 */
#define FP_MSKS_FLD	0x3f	/* exception masks field */
#define FP_PRC_FLD	0x300	/* precision control field */
#define	FP_RND_FLD	0xc00	/* rounding control field */

/*
 * FPU status word bit-field masks.
 */
#define FP_STKY_FLD	0x3f	/* sticky flags field */

/*
 * FPU control word bit-field offsets (shift counts).
 */
#define FP_MSKS_OFF	0	/* exception masks offset */
#define FP_PRC_OFF	8	/* precision control offset */
#define	FP_RND_OFF	10	/* rounding control offset */

/*
 * FPU status word bit-field offsets (shift counts).
 */
#define FP_STKY_OFF	0	/* sticky flags offset */

#ifdef __GNUCLIKE_ASM

#define	__fldcw(addr)	__asm __volatile("fldcw %0" : : "m" (*(addr)))
#define	__fldenv(addr)	__asm __volatile("fldenv %0" : : "m" (*(addr)))
#define	__fnclex()	__asm __volatile("fnclex")
#define	__fnstcw(addr)	__asm __volatile("fnstcw %0" : "=m" (*(addr)))
#define	__fnstenv(addr)	__asm __volatile("fnstenv %0" : "=m" (*(addr)))
#define	__fnstsw(addr)	__asm __volatile("fnstsw %0" : "=m" (*(addr)))

/*
 * Load the control word.  Be careful not to trap if there is a currently
 * unmasked exception (ones that will become freshly unmasked are not a
 * problem).  This case must be handled by a save/restore of the
 * environment or even of the full x87 state.  Accessing the environment
 * is very inefficient, so only do it when necessary.
 */
static __inline void
__fnldcw(unsigned short _cw, unsigned short _newcw)
{
	struct {
		unsigned _cw;
		unsigned _other[6];
	} _env;
	unsigned short _sw;

	if ((_cw & FP_MSKS_FLD) != FP_MSKS_FLD) {
		__fnstsw(&_sw);
		if (((_sw & ~_cw) & FP_STKY_FLD) != 0) {
			__fnstenv(&_env);
			_env._cw = _newcw;
			__fldenv(&_env);
			return;
		}
	}
	__fldcw(&_newcw);
}

static __inline fp_rnd_t
fpgetround(void)
{
	unsigned short _cw;

	__fnstcw(&_cw);
	return ((fp_rnd_t)((_cw & FP_RND_FLD) >> FP_RND_OFF));
}

static __inline fp_rnd_t
fpsetround(fp_rnd_t _m)
{
	fp_rnd_t _p;
	unsigned short _cw, _newcw;

	__fnstcw(&_cw);
	_p = (fp_rnd_t)((_cw & FP_RND_FLD) >> FP_RND_OFF);
	_newcw = _cw & ~FP_RND_FLD;
	_newcw |= (_m << FP_RND_OFF) & FP_RND_FLD;
	__fnldcw(_cw, _newcw);
	return (_p);
}

static __inline fp_prec_t
fpgetprec(void)
{
	unsigned short _cw;

	__fnstcw(&_cw);
	return ((fp_prec_t)((_cw & FP_PRC_FLD) >> FP_PRC_OFF));
}

static __inline fp_prec_t
fpsetprec(fp_prec_t _m)
{
	fp_prec_t _p;
	unsigned short _cw, _newcw;

	__fnstcw(&_cw);
	_p = (fp_prec_t)((_cw & FP_PRC_FLD) >> FP_PRC_OFF);
	_newcw = _cw & ~FP_PRC_FLD;
	_newcw |= (_m << FP_PRC_OFF) & FP_PRC_FLD;
	__fnldcw(_cw, _newcw);
	return (_p);
}

/*
 * Get or set the exception mask.
 * Note that the x87 mask bits are inverted by the API -- a mask bit of 1
 * means disable for x87 and SSE, but for fp*mask() it means enable.
 */

static __inline fp_except_t
fpgetmask(void)
{
	unsigned short _cw;

	__fnstcw(&_cw);
	return ((~_cw & FP_MSKS_FLD) >> FP_MSKS_OFF);
}

static __inline fp_except_t
fpsetmask(fp_except_t _m)
{
	fp_except_t _p;
	unsigned short _cw, _newcw;

	__fnstcw(&_cw);
	_p = (~_cw & FP_MSKS_FLD) >> FP_MSKS_OFF;
	_newcw = _cw & ~FP_MSKS_FLD;
	_newcw |= (~_m << FP_MSKS_OFF) & FP_MSKS_FLD;
	__fnldcw(_cw, _newcw);
	return (_p);
}

static __inline fp_except_t
fpgetsticky(void)
{
	unsigned _ex;
	unsigned short _sw;

	__fnstsw(&_sw);
	_ex = (_sw & FP_STKY_FLD) >> FP_STKY_OFF;
	return ((fp_except_t)_ex);
}

static __inline fp_except_t
fpresetsticky(fp_except_t _m)
{
	struct {
		unsigned _cw;
		unsigned _sw;
		unsigned _other[5];
	} _env;
	fp_except_t _p;

	_m &= FP_STKY_FLD >> FP_STKY_OFF;
	_p = fpgetsticky();
	if ((_p & ~_m) == _p)
		return (_p);
	if ((_p & ~_m) == 0) {
		__fnclex();
		return (_p);
	}
	__fnstenv(&_env);
	_env._sw &= ~_m;
	__fldenv(&_env);
	return (_p);
}

#endif /* __GNUCLIKE_ASM */

#endif /* !_MACHINE_IEEEFP_H_ */
OpenPOWER on IntegriCloud