1 /*-
2 * Copyright (c) 2004-2005 David Schultz <das@FreeBSD.ORG>
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 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD$
27 */
28
29 #ifndef _FENV_H_
30 #define _FENV_H_
31
32 #include <sys/cdefs.h>
33 #include <sys/_types.h>
34
35 #ifndef __fenv_static
36 #define __fenv_static static
37 #endif
38
39 typedef __uint16_t fexcept_t;
40
41 /* Exception flags */
42 #define FE_INVALID 0x01
43 #define FE_DENORMAL 0x02
44 #define FE_DIVBYZERO 0x04
45 #define FE_OVERFLOW 0x08
46 #define FE_UNDERFLOW 0x10
47 #define FE_INEXACT 0x20
48 #define FE_ALL_EXCEPT (FE_DIVBYZERO | FE_DENORMAL | FE_INEXACT | \
49 FE_INVALID | FE_OVERFLOW | FE_UNDERFLOW)
50
51 /* Rounding modes */
52 #define FE_TONEAREST 0x0000
53 #define FE_DOWNWARD 0x0400
54 #define FE_UPWARD 0x0800
55 #define FE_TOWARDZERO 0x0c00
56 #define _ROUND_MASK (FE_TONEAREST | FE_DOWNWARD | \
57 FE_UPWARD | FE_TOWARDZERO)
58
59 /*
60 * As compared to the x87 control word, the SSE unit's control word
61 * has the rounding control bits offset by 3 and the exception mask
62 * bits offset by 7.
63 */
64 #define _SSE_ROUND_SHIFT 3
65 #define _SSE_EMASK_SHIFT 7
66
67 #ifdef __i386__
68 /*
69 * To preserve binary compatibility with FreeBSD 5.3, we pack the
70 * mxcsr into some reserved fields, rather than changing sizeof(fenv_t).
71 */
72 typedef struct {
73 __uint16_t __control;
74 __uint16_t __mxcsr_hi;
75 __uint16_t __status;
76 __uint16_t __mxcsr_lo;
77 __uint32_t __tag;
78 char __other[16];
79 } fenv_t;
80 #else /* __amd64__ */
81 typedef struct {
82 struct {
83 __uint32_t __control;
84 __uint32_t __status;
85 __uint32_t __tag;
86 char __other[16];
87 } __x87;
88 __uint32_t __mxcsr;
89 } fenv_t;
90 #endif /* __i386__ */
91
92 __BEGIN_DECLS
93
94 /* Default floating-point environment */
95 extern const fenv_t __fe_dfl_env;
96 #define FE_DFL_ENV (&__fe_dfl_env)
97
98 #define __fldcw(__cw) __asm __volatile("fldcw %0" : : "m" (__cw))
99 #define __fldenv(__env) __asm __volatile("fldenv %0" : : "m" (__env))
100 #define __fldenvx(__env) __asm __volatile("fldenv %0" : : "m" (__env) \
101 : "st", "st(1)", "st(2)", "st(3)", "st(4)", \
102 "st(5)", "st(6)", "st(7)")
103 #define __fnclex() __asm __volatile("fnclex")
104 #define __fnstenv(__env) __asm __volatile("fnstenv %0" : "=m" (*(__env)))
105 #define __fnstcw(__cw) __asm __volatile("fnstcw %0" : "=m" (*(__cw)))
106 #define __fnstsw(__sw) __asm __volatile("fnstsw %0" : "=am" (*(__sw)))
107 #define __fwait() __asm __volatile("fwait")
108 #define __ldmxcsr(__csr) __asm __volatile("ldmxcsr %0" : : "m" (__csr))
109 #define __stmxcsr(__csr) __asm __volatile("stmxcsr %0" : "=m" (*(__csr)))
110
111 int fegetenv(fenv_t *__envp);
112 int feholdexcept(fenv_t *__envp);
113 int fesetexceptflag(const fexcept_t *__flagp, int __excepts);
114 int feraiseexcept(int __excepts);
115 int feupdateenv(const fenv_t *__envp);
116
117 __fenv_static inline int
fegetround(void)118 fegetround(void)
119 {
120 __uint16_t __control;
121
122 /*
123 * We assume that the x87 and the SSE unit agree on the
124 * rounding mode. Reading the control word on the x87 turns
125 * out to be about 5 times faster than reading it on the SSE
126 * unit on an Opteron 244.
127 */
128 __fnstcw(&__control);
129 return (__control & _ROUND_MASK);
130 }
131
132 #if __BSD_VISIBLE
133
134 int feenableexcept(int __mask);
135 int fedisableexcept(int __mask);
136
137 /* We currently provide no external definition of fegetexcept(). */
138 static inline int
fegetexcept(void)139 fegetexcept(void)
140 {
141 __uint16_t __control;
142
143 /*
144 * We assume that the masks for the x87 and the SSE unit are
145 * the same.
146 */
147 __fnstcw(&__control);
148 return (~__control & FE_ALL_EXCEPT);
149 }
150
151 #endif /* __BSD_VISIBLE */
152
153 #ifdef __i386__
154
155 /* After testing for SSE support once, we cache the result in __has_sse. */
156 enum __sse_support { __SSE_YES, __SSE_NO, __SSE_UNK };
157 extern enum __sse_support __has_sse;
158 int __test_sse(void);
159 #ifdef __SSE__
160 #define __HAS_SSE() 1
161 #else
162 #define __HAS_SSE() (__has_sse == __SSE_YES || \
163 (__has_sse == __SSE_UNK && __test_sse()))
164 #endif
165
166 #define __get_mxcsr(env) (((env).__mxcsr_hi << 16) | \
167 ((env).__mxcsr_lo))
168 #define __set_mxcsr(env, x) do { \
169 (env).__mxcsr_hi = (__uint32_t)(x) >> 16; \
170 (env).__mxcsr_lo = (__uint16_t)(x); \
171 } while (0)
172
173 __fenv_static inline int
feclearexcept(int __excepts)174 feclearexcept(int __excepts)
175 {
176 fenv_t __env;
177 __uint32_t __mxcsr;
178
179 if (__excepts == FE_ALL_EXCEPT) {
180 __fnclex();
181 } else {
182 __fnstenv(&__env);
183 __env.__status &= ~__excepts;
184 __fldenv(__env);
185 }
186 if (__HAS_SSE()) {
187 __stmxcsr(&__mxcsr);
188 __mxcsr &= ~__excepts;
189 __ldmxcsr(__mxcsr);
190 }
191 return (0);
192 }
193
194 __fenv_static inline int
fegetexceptflag(fexcept_t * __flagp,int __excepts)195 fegetexceptflag(fexcept_t *__flagp, int __excepts)
196 {
197 __uint32_t __mxcsr;
198 __uint16_t __status;
199
200 __fnstsw(&__status);
201 if (__HAS_SSE())
202 __stmxcsr(&__mxcsr);
203 else
204 __mxcsr = 0;
205 *__flagp = (__mxcsr | __status) & __excepts;
206 return (0);
207 }
208
209 __fenv_static inline int
fetestexcept(int __excepts)210 fetestexcept(int __excepts)
211 {
212 __uint32_t __mxcsr;
213 __uint16_t __status;
214
215 __fnstsw(&__status);
216 if (__HAS_SSE())
217 __stmxcsr(&__mxcsr);
218 else
219 __mxcsr = 0;
220 return ((__status | __mxcsr) & __excepts);
221 }
222
223 __fenv_static inline int
fesetround(int __round)224 fesetround(int __round)
225 {
226 __uint32_t __mxcsr;
227 __uint16_t __control;
228
229 if (__round & ~_ROUND_MASK)
230 return (-1);
231
232 __fnstcw(&__control);
233 __control &= ~_ROUND_MASK;
234 __control |= __round;
235 __fldcw(__control);
236
237 if (__HAS_SSE()) {
238 __stmxcsr(&__mxcsr);
239 __mxcsr &= ~(_ROUND_MASK << _SSE_ROUND_SHIFT);
240 __mxcsr |= __round << _SSE_ROUND_SHIFT;
241 __ldmxcsr(__mxcsr);
242 }
243
244 return (0);
245 }
246
247 __fenv_static inline int
fesetenv(const fenv_t * __envp)248 fesetenv(const fenv_t *__envp)
249 {
250 fenv_t __env = *__envp;
251 __uint32_t __mxcsr;
252
253 __mxcsr = __get_mxcsr(__env);
254 __set_mxcsr(__env, 0xffffffff);
255 /*
256 * XXX Using fldenvx() instead of fldenv() tells the compiler that this
257 * instruction clobbers the i387 register stack. This happens because
258 * we restore the tag word from the saved environment. Normally, this
259 * would happen anyway and we wouldn't care, because the ABI allows
260 * function calls to clobber the i387 regs. However, fesetenv() is
261 * inlined, so we need to be more careful.
262 */
263 __fldenvx(__env);
264 if (__HAS_SSE())
265 __ldmxcsr(__mxcsr);
266 return (0);
267 }
268
269 #else /* __amd64__ */
270
271 __fenv_static inline int
feclearexcept(int __excepts)272 feclearexcept(int __excepts)
273 {
274 fenv_t __env;
275
276 if (__excepts == FE_ALL_EXCEPT) {
277 __fnclex();
278 } else {
279 __fnstenv(&__env.__x87);
280 __env.__x87.__status &= ~__excepts;
281 __fldenv(__env.__x87);
282 }
283 __stmxcsr(&__env.__mxcsr);
284 __env.__mxcsr &= ~__excepts;
285 __ldmxcsr(__env.__mxcsr);
286 return (0);
287 }
288
289 __fenv_static inline int
fegetexceptflag(fexcept_t * __flagp,int __excepts)290 fegetexceptflag(fexcept_t *__flagp, int __excepts)
291 {
292 __uint32_t __mxcsr;
293 __uint16_t __status;
294
295 __stmxcsr(&__mxcsr);
296 __fnstsw(&__status);
297 *__flagp = (__mxcsr | __status) & __excepts;
298 return (0);
299 }
300
301 __fenv_static inline int
fetestexcept(int __excepts)302 fetestexcept(int __excepts)
303 {
304 __uint32_t __mxcsr;
305 __uint16_t __status;
306
307 __stmxcsr(&__mxcsr);
308 __fnstsw(&__status);
309 return ((__status | __mxcsr) & __excepts);
310 }
311
312 __fenv_static inline int
fesetround(int __round)313 fesetround(int __round)
314 {
315 __uint32_t __mxcsr;
316 __uint16_t __control;
317
318 if (__round & ~_ROUND_MASK)
319 return (-1);
320
321 __fnstcw(&__control);
322 __control &= ~_ROUND_MASK;
323 __control |= __round;
324 __fldcw(__control);
325
326 __stmxcsr(&__mxcsr);
327 __mxcsr &= ~(_ROUND_MASK << _SSE_ROUND_SHIFT);
328 __mxcsr |= __round << _SSE_ROUND_SHIFT;
329 __ldmxcsr(__mxcsr);
330
331 return (0);
332 }
333
334 __fenv_static inline int
fesetenv(const fenv_t * __envp)335 fesetenv(const fenv_t *__envp)
336 {
337
338 /*
339 * XXX Using fldenvx() instead of fldenv() tells the compiler that this
340 * instruction clobbers the i387 register stack. This happens because
341 * we restore the tag word from the saved environment. Normally, this
342 * would happen anyway and we wouldn't care, because the ABI allows
343 * function calls to clobber the i387 regs. However, fesetenv() is
344 * inlined, so we need to be more careful.
345 */
346 __fldenvx(__envp->__x87);
347 __ldmxcsr(__envp->__mxcsr);
348 return (0);
349 }
350
351 #endif /* __i386__ */
352
353 __END_DECLS
354
355 #endif /* !_FENV_H_ */
356