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 * $FreeBSD$
38 */
39
40 #ifndef _MACHINE_IEEEFP_H_
41 #define _MACHINE_IEEEFP_H_
42
43 /*
44 * Deprecated historical FPU control interface
45 *
46 * IEEE floating point type, constant and function definitions.
47 * XXX: FP*FLD and FP*OFF are undocumented pollution.
48 */
49
50 #ifndef _SYS_CDEFS_H_
51 #error this file needs sys/cdefs.h as a prerequisite
52 #endif
53
54 /*
55 * Rounding modes.
56 */
57 typedef enum {
58 FP_RN=0, /* round to nearest */
59 FP_RM, /* round down towards minus infinity */
60 FP_RP, /* round up towards plus infinity */
61 FP_RZ /* truncate */
62 } fp_rnd_t;
63
64 /*
65 * Precision (i.e., rounding precision) modes.
66 */
67 typedef enum {
68 FP_PS=0, /* 24 bit (single-precision) */
69 FP_PRS, /* reserved */
70 FP_PD, /* 53 bit (double-precision) */
71 FP_PE /* 64 bit (extended-precision) */
72 } fp_prec_t;
73
74 #define fp_except_t int
75
76 /*
77 * Exception bit masks.
78 */
79 #define FP_X_INV 0x01 /* invalid operation */
80 #define FP_X_DNML 0x02 /* denormal */
81 #define FP_X_DZ 0x04 /* zero divide */
82 #define FP_X_OFL 0x08 /* overflow */
83 #define FP_X_UFL 0x10 /* underflow */
84 #define FP_X_IMP 0x20 /* (im)precision */
85 #define FP_X_STK 0x40 /* stack fault */
86
87 /*
88 * FPU control word bit-field masks.
89 */
90 #define FP_MSKS_FLD 0x3f /* exception masks field */
91 #define FP_PRC_FLD 0x300 /* precision control field */
92 #define FP_RND_FLD 0xc00 /* rounding control field */
93
94 /*
95 * FPU status word bit-field masks.
96 */
97 #define FP_STKY_FLD 0x3f /* sticky flags field */
98
99 /*
100 * FPU control word bit-field offsets (shift counts).
101 */
102 #define FP_MSKS_OFF 0 /* exception masks offset */
103 #define FP_PRC_OFF 8 /* precision control offset */
104 #define FP_RND_OFF 10 /* rounding control offset */
105
106 /*
107 * FPU status word bit-field offsets (shift counts).
108 */
109 #define FP_STKY_OFF 0 /* sticky flags offset */
110
111 #ifdef __GNUCLIKE_ASM
112
113 #define __fldcw(addr) __asm __volatile("fldcw %0" : : "m" (*(addr)))
114 #define __fldenv(addr) __asm __volatile("fldenv %0" : : "m" (*(addr)))
115 #define __fnclex() __asm __volatile("fnclex")
116 #define __fnstcw(addr) __asm __volatile("fnstcw %0" : "=m" (*(addr)))
117 #define __fnstenv(addr) __asm __volatile("fnstenv %0" : "=m" (*(addr)))
118 #define __fnstsw(addr) __asm __volatile("fnstsw %0" : "=m" (*(addr)))
119 #define __ldmxcsr(addr) __asm __volatile("ldmxcsr %0" : : "m" (*(addr)))
120 #define __stmxcsr(addr) __asm __volatile("stmxcsr %0" : "=m" (*(addr)))
121
122 /*
123 * Load the control word. Be careful not to trap if there is a currently
124 * unmasked exception (ones that will become freshly unmasked are not a
125 * problem). This case must be handled by a save/restore of the
126 * environment or even of the full x87 state. Accessing the environment
127 * is very inefficient, so only do it when necessary.
128 */
129 static __inline void
130 __fnldcw(unsigned short _cw, unsigned short _newcw)
131 {
132 struct {
133 unsigned _cw;
134 unsigned _other[6];
135 } _env;
136 unsigned short _sw;
137
138 if ((_cw & FP_MSKS_FLD) != FP_MSKS_FLD) {
139 __fnstsw(&_sw);
140 if (((_sw & ~_cw) & FP_STKY_FLD) != 0) {
141 __fnstenv(&_env);
142 _env._cw = _newcw;
143 __fldenv(&_env);
144 return;
145 }
146 }
147 __fldcw(&_newcw);
148 }
149
150 static __inline fp_rnd_t
151 fpgetround(void)
152 {
153 unsigned short _cw;
154
155 __fnstcw(&_cw);
156 return ((fp_rnd_t)((_cw & FP_RND_FLD) >> FP_RND_OFF));
157 }
158
159 static __inline fp_rnd_t
160 fpsetround(fp_rnd_t _m)
161 {
162 fp_rnd_t _p;
163 unsigned short _cw, _newcw;
164
165 __fnstcw(&_cw);
166 _p = (fp_rnd_t)((_cw & FP_RND_FLD) >> FP_RND_OFF);
167 _newcw = _cw & ~FP_RND_FLD;
168 _newcw |= (_m << FP_RND_OFF) & FP_RND_FLD;
169 __fnldcw(_cw, _newcw);
170 return (_p);
171 }
172
173 static __inline fp_prec_t
174 fpgetprec(void)
175 {
176 unsigned short _cw;
177
178 __fnstcw(&_cw);
179 return ((fp_prec_t)((_cw & FP_PRC_FLD) >> FP_PRC_OFF));
180 }
181
182 static __inline fp_prec_t
183 fpsetprec(fp_prec_t _m)
184 {
185 fp_prec_t _p;
186 unsigned short _cw, _newcw;
187
188 __fnstcw(&_cw);
189 _p = (fp_prec_t)((_cw & FP_PRC_FLD) >> FP_PRC_OFF);
190 _newcw = _cw & ~FP_PRC_FLD;
191 _newcw |= (_m << FP_PRC_OFF) & FP_PRC_FLD;
192 __fnldcw(_cw, _newcw);
193 return (_p);
194 }
195
196 /*
197 * Get or set the exception mask.
198 * Note that the x87 mask bits are inverted by the API -- a mask bit of 1
199 * means disable for x87 and SSE, but for fp*mask() it means enable.
200 */
201
202 static __inline fp_except_t
203 fpgetmask(void)
204 {
205 unsigned short _cw;
206
207 __fnstcw(&_cw);
208 return ((~_cw & FP_MSKS_FLD) >> FP_MSKS_OFF);
209 }
210
211 static __inline fp_except_t
212 fpsetmask(fp_except_t _m)
213 {
214 fp_except_t _p;
215 unsigned short _cw, _newcw;
216
217 __fnstcw(&_cw);
218 _p = (~_cw & FP_MSKS_FLD) >> FP_MSKS_OFF;
219 _newcw = _cw & ~FP_MSKS_FLD;
220 _newcw |= (~_m << FP_MSKS_OFF) & FP_MSKS_FLD;
221 __fnldcw(_cw, _newcw);
222 return (_p);
223 }
224
225 static __inline fp_except_t
226 fpgetsticky(void)
227 {
228 unsigned _ex;
229 unsigned short _sw;
230
231 __fnstsw(&_sw);
232 _ex = (_sw & FP_STKY_FLD) >> FP_STKY_OFF;
233 return ((fp_except_t)_ex);
234 }
235
236 static __inline fp_except_t
237 fpresetsticky(fp_except_t _m)
238 {
239 struct {
240 unsigned _cw;
241 unsigned _sw;
242 unsigned _other[5];
243 } _env;
244 fp_except_t _p;
245
246 _m &= FP_STKY_FLD >> FP_STKY_OFF;
247 _p = fpgetsticky();
248 if ((_p & ~_m) == _p)
249 return (_p);
250 if ((_p & ~_m) == 0) {
251 __fnclex();
252 return (_p);
253 }
254 __fnstenv(&_env);
255 _env._sw &= ~_m;
256 __fldenv(&_env);
257 return (_p);
258 }
259
260 #endif /* __GNUCLIKE_ASM */
261
262 #endif /* !_MACHINE_IEEEFP_H_ */
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