1 /*-
2 * Copyright (c) 2003 Peter Wemm.
3 * Copyright (c) 1990 Andrew Moore, Talke Studio
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. All advertising materials mentioning features or use of this software
15 * must display the following acknowledgement:
16 * This product includes software developed by the University of
17 * California, Berkeley and its contributors.
18 * 4. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 * from: @(#) ieeefp.h 1.0 (Berkeley) 9/23/93
35 * $FreeBSD: releng/10.1/sys/i386/include/ieeefp.h 226607 2011-10-21 06:41:46Z das $
36 */
37
38 #ifndef _MACHINE_IEEEFP_H_
39 #define _MACHINE_IEEEFP_H_
40
41 /*
42 * Deprecated historical FPU control interface
43 *
44 * IEEE floating point type, constant and function definitions.
45 * XXX: FP*FLD and FP*OFF are undocumented pollution.
46 */
47
48 #ifndef _SYS_CDEFS_H_
49 #error this file needs sys/cdefs.h as a prerequisite
50 #endif
51
52 /*
53 * Rounding modes.
54 */
55 typedef enum {
56 FP_RN=0, /* round to nearest */
57 FP_RM, /* round down towards minus infinity */
58 FP_RP, /* round up towards plus infinity */
59 FP_RZ /* truncate */
60 } fp_rnd_t;
61
62 /*
63 * Precision (i.e., rounding precision) modes.
64 */
65 typedef enum {
66 FP_PS=0, /* 24 bit (single-precision) */
67 FP_PRS, /* reserved */
68 FP_PD, /* 53 bit (double-precision) */
69 FP_PE /* 64 bit (extended-precision) */
70 } fp_prec_t;
71
72 #define fp_except_t int
73
74 /*
75 * Exception bit masks.
76 */
77 #define FP_X_INV 0x01 /* invalid operation */
78 #define FP_X_DNML 0x02 /* denormal */
79 #define FP_X_DZ 0x04 /* zero divide */
80 #define FP_X_OFL 0x08 /* overflow */
81 #define FP_X_UFL 0x10 /* underflow */
82 #define FP_X_IMP 0x20 /* (im)precision */
83 #define FP_X_STK 0x40 /* stack fault */
84
85 /*
86 * FPU control word bit-field masks.
87 */
88 #define FP_MSKS_FLD 0x3f /* exception masks field */
89 #define FP_PRC_FLD 0x300 /* precision control field */
90 #define FP_RND_FLD 0xc00 /* rounding control field */
91
92 /*
93 * FPU status word bit-field masks.
94 */
95 #define FP_STKY_FLD 0x3f /* sticky flags field */
96
97 /*
98 * FPU control word bit-field offsets (shift counts).
99 */
100 #define FP_MSKS_OFF 0 /* exception masks offset */
101 #define FP_PRC_OFF 8 /* precision control offset */
102 #define FP_RND_OFF 10 /* rounding control offset */
103
104 /*
105 * FPU status word bit-field offsets (shift counts).
106 */
107 #define FP_STKY_OFF 0 /* sticky flags offset */
108
109 #ifdef __GNUCLIKE_ASM
110
111 #define __fldcw(addr) __asm __volatile("fldcw %0" : : "m" (*(addr)))
112 #define __fldenv(addr) __asm __volatile("fldenv %0" : : "m" (*(addr)))
113 #define __fnclex() __asm __volatile("fnclex")
114 #define __fnstcw(addr) __asm __volatile("fnstcw %0" : "=m" (*(addr)))
115 #define __fnstenv(addr) __asm __volatile("fnstenv %0" : "=m" (*(addr)))
116 #define __fnstsw(addr) __asm __volatile("fnstsw %0" : "=m" (*(addr)))
117
118 /*
119 * Load the control word. Be careful not to trap if there is a currently
120 * unmasked exception (ones that will become freshly unmasked are not a
121 * problem). This case must be handled by a save/restore of the
122 * environment or even of the full x87 state. Accessing the environment
123 * is very inefficient, so only do it when necessary.
124 */
125 static __inline void
126 __fnldcw(unsigned short _cw, unsigned short _newcw)
127 {
128 struct {
129 unsigned _cw;
130 unsigned _other[6];
131 } _env;
132 unsigned short _sw;
133
134 if ((_cw & FP_MSKS_FLD) != FP_MSKS_FLD) {
135 __fnstsw(&_sw);
136 if (((_sw & ~_cw) & FP_STKY_FLD) != 0) {
137 __fnstenv(&_env);
138 _env._cw = _newcw;
139 __fldenv(&_env);
140 return;
141 }
142 }
143 __fldcw(&_newcw);
144 }
145
146 static __inline fp_rnd_t
147 fpgetround(void)
148 {
149 unsigned short _cw;
150
151 __fnstcw(&_cw);
152 return ((fp_rnd_t)((_cw & FP_RND_FLD) >> FP_RND_OFF));
153 }
154
155 static __inline fp_rnd_t
156 fpsetround(fp_rnd_t _m)
157 {
158 fp_rnd_t _p;
159 unsigned short _cw, _newcw;
160
161 __fnstcw(&_cw);
162 _p = (fp_rnd_t)((_cw & FP_RND_FLD) >> FP_RND_OFF);
163 _newcw = _cw & ~FP_RND_FLD;
164 _newcw |= (_m << FP_RND_OFF) & FP_RND_FLD;
165 __fnldcw(_cw, _newcw);
166 return (_p);
167 }
168
169 static __inline fp_prec_t
170 fpgetprec(void)
171 {
172 unsigned short _cw;
173
174 __fnstcw(&_cw);
175 return ((fp_prec_t)((_cw & FP_PRC_FLD) >> FP_PRC_OFF));
176 }
177
178 static __inline fp_prec_t
179 fpsetprec(fp_prec_t _m)
180 {
181 fp_prec_t _p;
182 unsigned short _cw, _newcw;
183
184 __fnstcw(&_cw);
185 _p = (fp_prec_t)((_cw & FP_PRC_FLD) >> FP_PRC_OFF);
186 _newcw = _cw & ~FP_PRC_FLD;
187 _newcw |= (_m << FP_PRC_OFF) & FP_PRC_FLD;
188 __fnldcw(_cw, _newcw);
189 return (_p);
190 }
191
192 /*
193 * Get or set the exception mask.
194 * Note that the x87 mask bits are inverted by the API -- a mask bit of 1
195 * means disable for x87 and SSE, but for fp*mask() it means enable.
196 */
197
198 static __inline fp_except_t
199 fpgetmask(void)
200 {
201 unsigned short _cw;
202
203 __fnstcw(&_cw);
204 return ((~_cw & FP_MSKS_FLD) >> FP_MSKS_OFF);
205 }
206
207 static __inline fp_except_t
208 fpsetmask(fp_except_t _m)
209 {
210 fp_except_t _p;
211 unsigned short _cw, _newcw;
212
213 __fnstcw(&_cw);
214 _p = (~_cw & FP_MSKS_FLD) >> FP_MSKS_OFF;
215 _newcw = _cw & ~FP_MSKS_FLD;
216 _newcw |= (~_m << FP_MSKS_OFF) & FP_MSKS_FLD;
217 __fnldcw(_cw, _newcw);
218 return (_p);
219 }
220
221 static __inline fp_except_t
222 fpgetsticky(void)
223 {
224 unsigned _ex;
225 unsigned short _sw;
226
227 __fnstsw(&_sw);
228 _ex = (_sw & FP_STKY_FLD) >> FP_STKY_OFF;
229 return ((fp_except_t)_ex);
230 }
231
232 static __inline fp_except_t
233 fpresetsticky(fp_except_t _m)
234 {
235 struct {
236 unsigned _cw;
237 unsigned _sw;
238 unsigned _other[5];
239 } _env;
240 fp_except_t _p;
241
242 _m &= FP_STKY_FLD >> FP_STKY_OFF;
243 _p = fpgetsticky();
244 if ((_p & ~_m) == _p)
245 return (_p);
246 if ((_p & ~_m) == 0) {
247 __fnclex();
248 return (_p);
249 }
250 __fnstenv(&_env);
251 _env._sw &= ~_m;
252 __fldenv(&_env);
253 return (_p);
254 }
255
256 #endif /* __GNUCLIKE_ASM */
257
258 #endif /* !_MACHINE_IEEEFP_H_ */
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