1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2004-2005 David Schultz <das@FreeBSD.ORG> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 * 28 * $FreeBSD$ 29 */ 30 31 #ifndef _FENV_H_ 32 #define _FENV_H_ 33 34 #include <sys/cdefs.h> 35 #include <sys/_types.h> 36 #include <ieeefp.h> 37 38 #ifndef __fenv_static 39 #define __fenv_static static 40 #endif 41 42 typedef __uint16_t fexcept_t; 43 44 /* Exception flags */ 45 #define FE_INVALID 0x01 46 #define FE_DENORMAL 0x02 47 #define FE_DIVBYZERO 0x04 48 #define FE_OVERFLOW 0x08 49 #define FE_UNDERFLOW 0x10 50 #define FE_INEXACT 0x20 51 #define FE_ALL_EXCEPT (FE_DIVBYZERO | FE_DENORMAL | FE_INEXACT | \ 52 FE_INVALID | FE_OVERFLOW | FE_UNDERFLOW) 53 54 /* Rounding modes */ 55 #define FE_TONEAREST 0x0000 56 #define FE_DOWNWARD 0x0400 57 #define FE_UPWARD 0x0800 58 #define FE_TOWARDZERO 0x0c00 59 #define _ROUND_MASK (FE_TONEAREST | FE_DOWNWARD | \ 60 FE_UPWARD | FE_TOWARDZERO) 61 62 /* 63 * As compared to the x87 control word, the SSE unit's control word 64 * has the rounding control bits offset by 3 and the exception mask 65 * bits offset by 7. 66 */ 67 #define _SSE_ROUND_SHIFT 3 68 #define _SSE_EMASK_SHIFT 7 69 70 #ifdef __i386__ 71 /* 72 * To preserve binary compatibility with FreeBSD 5.3, we pack the 73 * mxcsr into some reserved fields, rather than changing sizeof(fenv_t). 74 */ 75 typedef struct { 76 __uint16_t __control; 77 __uint16_t __mxcsr_hi; 78 __uint16_t __status; 79 __uint16_t __mxcsr_lo; 80 __uint32_t __tag; 81 char __other[16]; 82 } fenv_t; 83 #else /* __amd64__ */ 84 typedef struct { 85 struct { 86 __uint32_t __control; 87 __uint32_t __status; 88 __uint32_t __tag; 89 char __other[16]; 90 } __x87; 91 __uint32_t __mxcsr; 92 } fenv_t; 93 #endif /* __i386__ */ 94 95 __BEGIN_DECLS 96 97 /* Default floating-point environment */ 98 extern const fenv_t __fe_dfl_env; 99 #define FE_DFL_ENV (&__fe_dfl_env) 100 101 #define __fldenvx(__env) __asm __volatile("fldenv %0" : : "m" (__env) \ 102 : "st", "st(1)", "st(2)", "st(3)", "st(4)", \ 103 "st(5)", "st(6)", "st(7)") 104 #define __fwait() __asm __volatile("fwait") 105 106 int fegetenv(fenv_t *__envp); 107 int feholdexcept(fenv_t *__envp); 108 int fesetexceptflag(const fexcept_t *__flagp, int __excepts); 109 int feraiseexcept(int __excepts); 110 int feupdateenv(const fenv_t *__envp); 111 112 __fenv_static inline int 113 fegetround(void) 114 { 115 __uint16_t __control; 116 117 /* 118 * We assume that the x87 and the SSE unit agree on the 119 * rounding mode. Reading the control word on the x87 turns 120 * out to be about 5 times faster than reading it on the SSE 121 * unit on an Opteron 244. 122 */ 123 __fnstcw(&__control); 124 return (__control & _ROUND_MASK); 125 } 126 127 #if __BSD_VISIBLE 128 129 int feenableexcept(int __mask); 130 int fedisableexcept(int __mask); 131 132 /* We currently provide no external definition of fegetexcept(). */ 133 static inline int 134 fegetexcept(void) 135 { 136 __uint16_t __control; 137 138 /* 139 * We assume that the masks for the x87 and the SSE unit are 140 * the same. 141 */ 142 __fnstcw(&__control); 143 return (~__control & FE_ALL_EXCEPT); 144 } 145 146 #endif /* __BSD_VISIBLE */ 147 148 #ifdef __i386__ 149 150 /* After testing for SSE support once, we cache the result in __has_sse. */ 151 enum __sse_support { __SSE_YES, __SSE_NO, __SSE_UNK }; 152 extern enum __sse_support __has_sse; 153 int __test_sse(void); 154 #ifdef __SSE__ 155 #define __HAS_SSE() 1 156 #else 157 #define __HAS_SSE() (__has_sse == __SSE_YES || \ 158 (__has_sse == __SSE_UNK && __test_sse())) 159 #endif 160 161 #define __get_mxcsr(env) (((env).__mxcsr_hi << 16) | \ 162 ((env).__mxcsr_lo)) 163 #define __set_mxcsr(env, x) do { \ 164 (env).__mxcsr_hi = (__uint32_t)(x) >> 16; \ 165 (env).__mxcsr_lo = (__uint16_t)(x); \ 166 } while (0) 167 168 __fenv_static inline int 169 feclearexcept(int __excepts) 170 { 171 fenv_t __env; 172 __uint32_t __mxcsr; 173 174 if (__excepts == FE_ALL_EXCEPT) { 175 __fnclex(); 176 } else { 177 __fnstenv(&__env); 178 __env.__status &= ~__excepts; 179 __fldenv(&__env); 180 } 181 if (__HAS_SSE()) { 182 __stmxcsr(&__mxcsr); 183 __mxcsr &= ~__excepts; 184 __ldmxcsr(&__mxcsr); 185 } 186 return (0); 187 } 188 189 __fenv_static inline int 190 fegetexceptflag(fexcept_t *__flagp, int __excepts) 191 { 192 __uint32_t __mxcsr; 193 __uint16_t __status; 194 195 __fnstsw(&__status); 196 if (__HAS_SSE()) 197 __stmxcsr(&__mxcsr); 198 else 199 __mxcsr = 0; 200 *__flagp = (__mxcsr | __status) & __excepts; 201 return (0); 202 } 203 204 __fenv_static inline int 205 fetestexcept(int __excepts) 206 { 207 __uint32_t __mxcsr; 208 __uint16_t __status; 209 210 __fnstsw(&__status); 211 if (__HAS_SSE()) 212 __stmxcsr(&__mxcsr); 213 else 214 __mxcsr = 0; 215 return ((__status | __mxcsr) & __excepts); 216 } 217 218 __fenv_static inline int 219 fesetround(int __round) 220 { 221 __uint32_t __mxcsr; 222 __uint16_t __control; 223 224 if (__round & ~_ROUND_MASK) 225 return (-1); 226 227 __fnstcw(&__control); 228 __control &= ~_ROUND_MASK; 229 __control |= __round; 230 __fldcw(&__control); 231 232 if (__HAS_SSE()) { 233 __stmxcsr(&__mxcsr); 234 __mxcsr &= ~(_ROUND_MASK << _SSE_ROUND_SHIFT); 235 __mxcsr |= __round << _SSE_ROUND_SHIFT; 236 __ldmxcsr(&__mxcsr); 237 } 238 239 return (0); 240 } 241 242 __fenv_static inline int 243 fesetenv(const fenv_t *__envp) 244 { 245 fenv_t __env = *__envp; 246 __uint32_t __mxcsr; 247 248 __mxcsr = __get_mxcsr(__env); 249 __set_mxcsr(__env, 0xffffffff); 250 /* 251 * XXX Using fldenvx() instead of fldenv() tells the compiler that this 252 * instruction clobbers the i387 register stack. This happens because 253 * we restore the tag word from the saved environment. Normally, this 254 * would happen anyway and we wouldn't care, because the ABI allows 255 * function calls to clobber the i387 regs. However, fesetenv() is 256 * inlined, so we need to be more careful. 257 */ 258 __fldenvx(__env); 259 if (__HAS_SSE()) 260 __ldmxcsr(&__mxcsr); 261 return (0); 262 } 263 264 #else /* __amd64__ */ 265 266 __fenv_static inline int 267 feclearexcept(int __excepts) 268 { 269 fenv_t __env; 270 271 if (__excepts == FE_ALL_EXCEPT) { 272 __fnclex(); 273 } else { 274 __fnstenv(&__env.__x87); 275 __env.__x87.__status &= ~__excepts; 276 __fldenv(&__env.__x87); 277 } 278 __stmxcsr(&__env.__mxcsr); 279 __env.__mxcsr &= ~__excepts; 280 __ldmxcsr(&__env.__mxcsr); 281 return (0); 282 } 283 284 __fenv_static inline int 285 fegetexceptflag(fexcept_t *__flagp, int __excepts) 286 { 287 __uint32_t __mxcsr; 288 __uint16_t __status; 289 290 __stmxcsr(&__mxcsr); 291 __fnstsw(&__status); 292 *__flagp = (__mxcsr | __status) & __excepts; 293 return (0); 294 } 295 296 __fenv_static inline int 297 fetestexcept(int __excepts) 298 { 299 __uint32_t __mxcsr; 300 __uint16_t __status; 301 302 __stmxcsr(&__mxcsr); 303 __fnstsw(&__status); 304 return ((__status | __mxcsr) & __excepts); 305 } 306 307 __fenv_static inline int 308 fesetround(int __round) 309 { 310 __uint32_t __mxcsr; 311 __uint16_t __control; 312 313 if (__round & ~_ROUND_MASK) 314 return (-1); 315 316 __fnstcw(&__control); 317 __control &= ~_ROUND_MASK; 318 __control |= __round; 319 __fldcw(&__control); 320 321 __stmxcsr(&__mxcsr); 322 __mxcsr &= ~(_ROUND_MASK << _SSE_ROUND_SHIFT); 323 __mxcsr |= __round << _SSE_ROUND_SHIFT; 324 __ldmxcsr(&__mxcsr); 325 326 return (0); 327 } 328 329 __fenv_static inline int 330 fesetenv(const fenv_t *__envp) 331 { 332 333 /* 334 * XXX Using fldenvx() instead of fldenv() tells the compiler that this 335 * instruction clobbers the i387 register stack. This happens because 336 * we restore the tag word from the saved environment. Normally, this 337 * would happen anyway and we wouldn't care, because the ABI allows 338 * function calls to clobber the i387 regs. However, fesetenv() is 339 * inlined, so we need to be more careful. 340 */ 341 __fldenvx(__envp->__x87); 342 __ldmxcsr(&__envp->__mxcsr); 343 return (0); 344 } 345 346 #endif /* __i386__ */ 347 348 __END_DECLS 349 350 #endif /* !_FENV_H_ */ 351