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 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 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 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 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 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 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 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 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 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 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 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 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