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