fenv.c revision 1.2.2.2
1 1.2.2.2 snj /* $NetBSD: fenv.c,v 1.2.2.2 2015/01/20 20:57:24 snj Exp $ */ 2 1.2.2.2 snj 3 1.2.2.2 snj /*- 4 1.2.2.2 snj * Copyright (c) 2004-2005 David Schultz <das (at) FreeBSD.ORG> 5 1.2.2.2 snj * All rights reserved. 6 1.2.2.2 snj * 7 1.2.2.2 snj * Redistribution and use in source and binary forms, with or without 8 1.2.2.2 snj * modification, are permitted provided that the following conditions 9 1.2.2.2 snj * are met: 10 1.2.2.2 snj * 1. Redistributions of source code must retain the above copyright 11 1.2.2.2 snj * notice, this list of conditions and the following disclaimer. 12 1.2.2.2 snj * 2. Redistributions in binary form must reproduce the above copyright 13 1.2.2.2 snj * notice, this list of conditions and the following disclaimer in the 14 1.2.2.2 snj * documentation and/or other materials provided with the distribution. 15 1.2.2.2 snj * 16 1.2.2.2 snj * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 1.2.2.2 snj * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 1.2.2.2 snj * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 1.2.2.2 snj * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 1.2.2.2 snj * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 1.2.2.2 snj * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 1.2.2.2 snj * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 1.2.2.2 snj * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 1.2.2.2 snj * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 1.2.2.2 snj */ 26 1.2.2.2 snj #include <sys/cdefs.h> 27 1.2.2.2 snj __RCSID("$NetBSD: fenv.c,v 1.2.2.2 2015/01/20 20:57:24 snj Exp $"); 28 1.2.2.2 snj 29 1.2.2.2 snj #include <assert.h> 30 1.2.2.2 snj #include <fenv.h> 31 1.2.2.2 snj 32 1.2.2.2 snj /* 33 1.2.2.2 snj * Convert from exception flags (__BITS(27,32)) to exception enable bits 34 1.2.2.2 snj * (__BITS(5,0)) by right-shifting this much: 35 1.2.2.2 snj */ 36 1.2.2.2 snj #define FE_FLAGS_SHIFT 27 37 1.2.2.2 snj 38 1.2.2.2 snj /* 39 1.2.2.2 snj * Mask all rounding mode bits 40 1.2.2.2 snj */ 41 1.2.2.2 snj #define FE_ROUND_MASK (FE_TONEAREST | FE_DOWNWARD | \ 42 1.2.2.2 snj FE_UPWARD | FE_TOWARDZERO) 43 1.2.2.2 snj 44 1.2.2.2 snj /* Load lower 32 bits from floating-point state register */ 45 1.2.2.2 snj static inline uint32_t 46 1.2.2.2 snj readfpsr(void) 47 1.2.2.2 snj { 48 1.2.2.2 snj uint32_t rv; 49 1.2.2.2 snj 50 1.2.2.2 snj __asm__ __volatile__ ("fstws %%fr0, %0" : "=m"(rv)); 51 1.2.2.2 snj return rv; 52 1.2.2.2 snj } 53 1.2.2.2 snj 54 1.2.2.2 snj /* Save floating-point state register */ 55 1.2.2.2 snj static inline void 56 1.2.2.2 snj writefpsr(uint32_t val) 57 1.2.2.2 snj { 58 1.2.2.2 snj __asm__ __volatile__("fldws %0,%%fr0" : : "m"(val)); 59 1.2.2.2 snj } 60 1.2.2.2 snj 61 1.2.2.2 snj /* 62 1.2.2.2 snj * The feclearexcept() function clears the supported floating-point exceptions 63 1.2.2.2 snj * represented by `excepts'. 64 1.2.2.2 snj */ 65 1.2.2.2 snj int 66 1.2.2.2 snj feclearexcept(int excepts) 67 1.2.2.2 snj { 68 1.2.2.2 snj fexcept_t r; 69 1.2.2.2 snj int ex; 70 1.2.2.2 snj 71 1.2.2.2 snj _DIAGASSERT((excepts & ~FE_ALL_EXCEPT) == 0); 72 1.2.2.2 snj 73 1.2.2.2 snj ex = (excepts & FE_ALL_EXCEPT) << FE_FLAGS_SHIFT; 74 1.2.2.2 snj 75 1.2.2.2 snj r = readfpsr(); 76 1.2.2.2 snj r &= ~ex; 77 1.2.2.2 snj writefpsr(r); 78 1.2.2.2 snj 79 1.2.2.2 snj /* Success */ 80 1.2.2.2 snj return 0; 81 1.2.2.2 snj } 82 1.2.2.2 snj 83 1.2.2.2 snj /* 84 1.2.2.2 snj * The fegetexceptflag() function stores an implementation-defined 85 1.2.2.2 snj * representation of the states of the floating-point status flags indicated 86 1.2.2.2 snj * by the argument excepts in the object pointed to by the argument flagp. 87 1.2.2.2 snj */ 88 1.2.2.2 snj int 89 1.2.2.2 snj fegetexceptflag(fexcept_t *flagp, int excepts) 90 1.2.2.2 snj { 91 1.2.2.2 snj fexcept_t r; 92 1.2.2.2 snj int ex; 93 1.2.2.2 snj 94 1.2.2.2 snj _DIAGASSERT(flagp != NULL); 95 1.2.2.2 snj _DIAGASSERT((excepts & ~_FE_ALL_EXCEPT) == 0); 96 1.2.2.2 snj 97 1.2.2.2 snj ex = (excepts & FE_ALL_EXCEPT) << FE_FLAGS_SHIFT; 98 1.2.2.2 snj 99 1.2.2.2 snj r = readfpsr(); 100 1.2.2.2 snj *flagp = (r & ex) >> FE_FLAGS_SHIFT; 101 1.2.2.2 snj 102 1.2.2.2 snj /* Success */ 103 1.2.2.2 snj return 0; 104 1.2.2.2 snj } 105 1.2.2.2 snj 106 1.2.2.2 snj 107 1.2.2.2 snj /* 108 1.2.2.2 snj * This function sets the floating-point status flags indicated by the argument 109 1.2.2.2 snj * `excepts' to the states stored in the object pointed to by `flagp'. It does 110 1.2.2.2 snj * NOT raise any floating-point exceptions, but only sets the state of the flags. 111 1.2.2.2 snj */ 112 1.2.2.2 snj int 113 1.2.2.2 snj fesetexceptflag(const fexcept_t *flagp, int excepts) 114 1.2.2.2 snj { 115 1.2.2.2 snj fexcept_t r; 116 1.2.2.2 snj int ex; 117 1.2.2.2 snj 118 1.2.2.2 snj _DIAGASSERT(flagp != NULL); 119 1.2.2.2 snj _DIAGASSERT((excepts & ~FE_ALL_EXCEPT) == 0); 120 1.2.2.2 snj 121 1.2.2.2 snj ex = (excepts & FE_ALL_EXCEPT) << FE_FLAGS_SHIFT; 122 1.2.2.2 snj 123 1.2.2.2 snj r = readfpsr(); 124 1.2.2.2 snj r &= ~ex; 125 1.2.2.2 snj r |= (*flagp << FE_FLAGS_SHIFT) & ex; 126 1.2.2.2 snj writefpsr(r); 127 1.2.2.2 snj 128 1.2.2.2 snj /* Success */ 129 1.2.2.2 snj return 0; 130 1.2.2.2 snj } 131 1.2.2.2 snj 132 1.2.2.2 snj /* 133 1.2.2.2 snj * The feraiseexcept() function raises the supported floating-point exceptions 134 1.2.2.2 snj * represented by the argument `excepts'. 135 1.2.2.2 snj * 136 1.2.2.2 snj * The order in which these floating-point exceptions are raised is unspecified 137 1.2.2.2 snj * (by the standard). 138 1.2.2.2 snj */ 139 1.2.2.2 snj int 140 1.2.2.2 snj feraiseexcept(int excepts) 141 1.2.2.2 snj { 142 1.2.2.2 snj volatile double d; 143 1.2.2.2 snj int ex; 144 1.2.2.2 snj 145 1.2.2.2 snj _DIAGASSERT((excepts & ~FE_ALL_EXCEPT) == 0); 146 1.2.2.2 snj 147 1.2.2.2 snj ex = excepts & FE_ALL_EXCEPT; 148 1.2.2.2 snj 149 1.2.2.2 snj /* 150 1.2.2.2 snj * With a compiler that supports the FENV_ACCESS pragma properly, simple 151 1.2.2.2 snj * expressions like '0.0 / 0.0' should be sufficient to generate traps. 152 1.2.2.2 snj * Unfortunately, we need to bring a volatile variable into the equation 153 1.2.2.2 snj * to prevent incorrect optimizations. 154 1.2.2.2 snj */ 155 1.2.2.2 snj if (ex & FE_INVALID) { 156 1.2.2.2 snj d = 0.0; 157 1.2.2.2 snj d = 0.0 / d; 158 1.2.2.2 snj } 159 1.2.2.2 snj if (ex & FE_DIVBYZERO) { 160 1.2.2.2 snj d = 0.0; 161 1.2.2.2 snj d = 1.0 / d; 162 1.2.2.2 snj } 163 1.2.2.2 snj if (ex & FE_OVERFLOW) { 164 1.2.2.2 snj d = 0x1.ffp1023; 165 1.2.2.2 snj d *= 2.0; 166 1.2.2.2 snj } 167 1.2.2.2 snj if (ex & FE_UNDERFLOW) { 168 1.2.2.2 snj d = 0x1p-1022; 169 1.2.2.2 snj d /= 0x1p1023; 170 1.2.2.2 snj } 171 1.2.2.2 snj if (ex & FE_INEXACT) { 172 1.2.2.2 snj d = 0x1p-1022; 173 1.2.2.2 snj d += 1.0; 174 1.2.2.2 snj } 175 1.2.2.2 snj 176 1.2.2.2 snj /* Success */ 177 1.2.2.2 snj return 0; 178 1.2.2.2 snj } 179 1.2.2.2 snj 180 1.2.2.2 snj /* 181 1.2.2.2 snj * The fetestexcept() function determines which of a specified subset of the 182 1.2.2.2 snj * floating-point exception flags are currently set. The `excepts' argument 183 1.2.2.2 snj * specifies the floating-point status flags to be queried. 184 1.2.2.2 snj */ 185 1.2.2.2 snj int 186 1.2.2.2 snj fetestexcept(int excepts) 187 1.2.2.2 snj { 188 1.2.2.2 snj fexcept_t r; 189 1.2.2.2 snj 190 1.2.2.2 snj _DIAGASSERT((excepts & ~FE_ALL_EXCEPT) == 0); 191 1.2.2.2 snj 192 1.2.2.2 snj r = readfpsr(); 193 1.2.2.2 snj 194 1.2.2.2 snj return (r >> FE_FLAGS_SHIFT) & (excepts & FE_ALL_EXCEPT); 195 1.2.2.2 snj } 196 1.2.2.2 snj 197 1.2.2.2 snj /* 198 1.2.2.2 snj * The fegetround() function gets the current rounding direction. 199 1.2.2.2 snj */ 200 1.2.2.2 snj int 201 1.2.2.2 snj fegetround(void) 202 1.2.2.2 snj { 203 1.2.2.2 snj fenv_t r; 204 1.2.2.2 snj 205 1.2.2.2 snj r = readfpsr(); 206 1.2.2.2 snj 207 1.2.2.2 snj return r & FE_ROUND_MASK; 208 1.2.2.2 snj } 209 1.2.2.2 snj 210 1.2.2.2 snj /* 211 1.2.2.2 snj * The fesetround() function establishes the rounding direction represented by 212 1.2.2.2 snj * its argument `round'. If the argument is not equal to the value of a rounding 213 1.2.2.2 snj * direction macro, the rounding direction is not changed. 214 1.2.2.2 snj */ 215 1.2.2.2 snj int 216 1.2.2.2 snj fesetround(int round) 217 1.2.2.2 snj { 218 1.2.2.2 snj fenv_t r; 219 1.2.2.2 snj 220 1.2.2.2 snj _DIAGASSERT((round & ~FE_ROUND_MASK) == 0); 221 1.2.2.2 snj if (round & ~FE_ROUND_MASK) 222 1.2.2.2 snj return -1; 223 1.2.2.2 snj 224 1.2.2.2 snj r = readfpsr(); 225 1.2.2.2 snj r &= ~FE_ROUND_MASK; 226 1.2.2.2 snj r |= round; 227 1.2.2.2 snj writefpsr(r); 228 1.2.2.2 snj 229 1.2.2.2 snj /* Success */ 230 1.2.2.2 snj return 0; 231 1.2.2.2 snj } 232 1.2.2.2 snj 233 1.2.2.2 snj /* 234 1.2.2.2 snj * The fegetenv() function attempts to store the current floating-point 235 1.2.2.2 snj * environment in the object pointed to by envp. 236 1.2.2.2 snj */ 237 1.2.2.2 snj int 238 1.2.2.2 snj fegetenv(fenv_t *envp) 239 1.2.2.2 snj { 240 1.2.2.2 snj _DIAGASSERT(envp != NULL); 241 1.2.2.2 snj 242 1.2.2.2 snj *envp = readfpsr(); 243 1.2.2.2 snj 244 1.2.2.2 snj /* Success */ 245 1.2.2.2 snj return 0; 246 1.2.2.2 snj } 247 1.2.2.2 snj 248 1.2.2.2 snj 249 1.2.2.2 snj /* 250 1.2.2.2 snj * The feholdexcept() function saves the current floating-point environment 251 1.2.2.2 snj * in the object pointed to by envp, clears the floating-point status flags, and 252 1.2.2.2 snj * then installs a non-stop (continue on floating-point exceptions) mode, if 253 1.2.2.2 snj * available, for all floating-point exceptions. 254 1.2.2.2 snj */ 255 1.2.2.2 snj int 256 1.2.2.2 snj feholdexcept(fenv_t *envp) 257 1.2.2.2 snj { 258 1.2.2.2 snj fenv_t r; 259 1.2.2.2 snj 260 1.2.2.2 snj _DIAGASSERT(envp != NULL); 261 1.2.2.2 snj 262 1.2.2.2 snj r = readfpsr(); 263 1.2.2.2 snj *envp = r; 264 1.2.2.2 snj r &= ~FE_ALL_EXCEPT; 265 1.2.2.2 snj writefpsr(r); 266 1.2.2.2 snj 267 1.2.2.2 snj /* Success */ 268 1.2.2.2 snj return 0; 269 1.2.2.2 snj } 270 1.2.2.2 snj 271 1.2.2.2 snj /* 272 1.2.2.2 snj * The fesetenv() function attempts to establish the floating-point environment 273 1.2.2.2 snj * represented by the object pointed to by envp. The argument `envp' points 274 1.2.2.2 snj * to an object set by a call to fegetenv() or feholdexcept(), or equal a 275 1.2.2.2 snj * floating-point environment macro. The fesetenv() function does not raise 276 1.2.2.2 snj * floating-point exceptions, but only installs the state of the floating-point 277 1.2.2.2 snj * status flags represented through its argument. 278 1.2.2.2 snj */ 279 1.2.2.2 snj int 280 1.2.2.2 snj fesetenv(const fenv_t *envp) 281 1.2.2.2 snj { 282 1.2.2.2 snj _DIAGASSERT(envp != NULL); 283 1.2.2.2 snj 284 1.2.2.2 snj writefpsr(*envp); 285 1.2.2.2 snj 286 1.2.2.2 snj /* Success */ 287 1.2.2.2 snj return 0; 288 1.2.2.2 snj } 289 1.2.2.2 snj 290 1.2.2.2 snj 291 1.2.2.2 snj /* 292 1.2.2.2 snj * The feupdateenv() function saves the currently raised floating-point 293 1.2.2.2 snj * exceptions in its automatic storage, installs the floating-point environment 294 1.2.2.2 snj * represented by the object pointed to by `envp', and then raises the saved 295 1.2.2.2 snj * floating-point exceptions. The argument `envp' shall point to an object set 296 1.2.2.2 snj * by a call to feholdexcept() or fegetenv(), or equal a floating-point 297 1.2.2.2 snj * environment macro. 298 1.2.2.2 snj */ 299 1.2.2.2 snj int 300 1.2.2.2 snj feupdateenv(const fenv_t *envp) 301 1.2.2.2 snj { 302 1.2.2.2 snj fexcept_t r; 303 1.2.2.2 snj 304 1.2.2.2 snj _DIAGASSERT(envp != NULL); 305 1.2.2.2 snj 306 1.2.2.2 snj r = readfpsr(); 307 1.2.2.2 snj writefpsr(*envp); 308 1.2.2.2 snj 309 1.2.2.2 snj _DIAGASSERT((r & ~FE_ALL_EXCEPT) == 0); 310 1.2.2.2 snj feraiseexcept(r & FE_ALL_EXCEPT); 311 1.2.2.2 snj 312 1.2.2.2 snj /* Success */ 313 1.2.2.2 snj return 0; 314 1.2.2.2 snj } 315 1.2.2.2 snj 316 1.2.2.2 snj /* 317 1.2.2.2 snj * The following functions are extentions to the standard 318 1.2.2.2 snj */ 319 1.2.2.2 snj int 320 1.2.2.2 snj feenableexcept(int mask) 321 1.2.2.2 snj { 322 1.2.2.2 snj fenv_t old_r, new_r; 323 1.2.2.2 snj 324 1.2.2.2 snj old_r = readfpsr(); 325 1.2.2.2 snj new_r = old_r | (mask & FE_ALL_EXCEPT); 326 1.2.2.2 snj writefpsr(new_r); 327 1.2.2.2 snj 328 1.2.2.2 snj return old_r & FE_ALL_EXCEPT; 329 1.2.2.2 snj } 330 1.2.2.2 snj 331 1.2.2.2 snj int 332 1.2.2.2 snj fedisableexcept(int mask) 333 1.2.2.2 snj { 334 1.2.2.2 snj fenv_t old_r, new_r; 335 1.2.2.2 snj 336 1.2.2.2 snj old_r = readfpsr(); 337 1.2.2.2 snj new_r = old_r & ~(mask & FE_ALL_EXCEPT); 338 1.2.2.2 snj writefpsr(new_r); 339 1.2.2.2 snj 340 1.2.2.2 snj return old_r & FE_ALL_EXCEPT; 341 1.2.2.2 snj } 342 1.2.2.2 snj 343 1.2.2.2 snj int 344 1.2.2.2 snj fegetexcept(void) 345 1.2.2.2 snj { 346 1.2.2.2 snj fenv_t r; 347 1.2.2.2 snj 348 1.2.2.2 snj r = readfpsr(); 349 1.2.2.2 snj return r & FE_ALL_EXCEPT; 350 1.2.2.2 snj } 351
Indexes created Thu Oct 02 10:09:58 GMT 2025