lib/fenv-except-tracking-clear.c

   1 /* Functions for tracking which floating-point exceptions have occurred.
   2    Copyright (C) 1997-2025 Free Software Foundation, Inc.
   3
   4    This file is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU Lesser General Public License as
   6    published by the Free Software Foundation; either version 2.1 of the
   7    License, or (at your option) any later version.
   8
   9    This file is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 /* Based on glibc/sysdeps/<cpu>/{fclrexcpt.c,fraiseexcpt.c,ftestexcept.c}
  18    together with glibc/sysdeps/<cpu>/{fpu_control.h,fenv_private.h,fenv_libc.h}.  */
  19
  20 #include <config.h>
  21
  22 /* Specification.  */
  23 #include <fenv.h>
  24
  25 #include "fenv-private.h"
  26
  27 #if defined __GNUC__ || defined __clang__ || defined _MSC_VER
  28
  29 # if (defined __x86_64__ || defined _M_X64) || (defined __i386 || defined _M_IX86)
  30
  31 int
  32 feclearexcept (int exceptions)
  33 {
  34   exceptions &= FE_ALL_EXCEPT;
  35
  36 #  if defined _MSC_VER
  37
  38   exceptions = exceptions_to_x86hardware (exceptions);
  39
  40   /* Clear the bits only in the SSE unit.  */
  41   unsigned int mxcsr, orig_mxcsr;
  42   _FPU_GETSSECW (orig_mxcsr);
  43   mxcsr = orig_mxcsr & ~exceptions;
  44   if (mxcsr != orig_mxcsr)
  45     _FPU_SETSSECW (mxcsr);
  46
  47 #  else
  48
  49   /* Clear the bits in the 387 unit.  */
  50   x86_387_fenv_t env;
  51   __asm__ __volatile__ ("fnstenv %0" : "=m" (*&env));
  52   /* Note: fnstenv masks all floating-point exceptions until the fldenv
  53      below.  */
  54   env.__status_word &= ~exceptions;
  55   __asm__ __volatile__ ("fldenv %0" : : "m" (*&env));
  56
  57   if (CPU_HAS_SSE ())
  58     {
  59       /* Clear the bits in the SSE unit as well.  */
  60       unsigned int mxcsr, orig_mxcsr;
  61       _FPU_GETSSECW (orig_mxcsr);
  62       mxcsr = orig_mxcsr & ~exceptions;
  63       if (mxcsr != orig_mxcsr)
  64         _FPU_SETSSECW (mxcsr);
  65     }
  66
  67 #  endif
  68
  69   return 0;
  70 }
  71
  72 # elif defined __aarch64__ /* arm64 */
  73
  74 int
  75 feclearexcept (int exceptions)
  76 {
  77   exceptions &= FE_ALL_EXCEPT;
  78
  79   unsigned long fpsr, orig_fpsr;
  80   _FPU_GETFPSR (orig_fpsr);
  81   fpsr = orig_fpsr & ~exceptions;
  82   if (fpsr != orig_fpsr)
  83     _FPU_SETFPSR (fpsr);
  84
  85   return 0;
  86 }
  87
  88 # elif defined __arm__
  89
  90 int
  91 feclearexcept (int exceptions)
  92 {
  93   exceptions &= FE_ALL_EXCEPT;
  94
  95 #  ifdef __SOFTFP__
  96   if (exceptions != 0)
  97     return -1;
  98 #  else
  99   unsigned int fpscr, orig_fpscr;
 100   _FPU_GETCW (orig_fpscr);
 101   fpscr = orig_fpscr & ~exceptions;
 102   if (fpscr != orig_fpscr)
 103     _FPU_SETCW (fpscr);
 104 #  endif
 105   return 0;
 106 }
 107
 108 # elif defined __alpha
 109
 110 int
 111 feclearexcept (int exceptions)
 112 {
 113   exceptions &= FE_ALL_EXCEPT;
 114
 115   unsigned long swcr, orig_swcr;
 116   orig_swcr = __ieee_get_fp_control ();
 117   swcr = orig_swcr & ~exceptions;
 118   if (swcr != orig_swcr)
 119     __ieee_set_fp_control (swcr);
 120
 121   return 0;
 122 }
 123
 124 # elif defined __hppa
 125
 126 int
 127 feclearexcept (int exceptions)
 128 {
 129   exceptions &= FE_ALL_EXCEPT;
 130
 131   union { unsigned long long fpreg; unsigned int halfreg[2]; } s;
 132   /* Get the current status word. */
 133   __asm__ __volatile__ ("fstd %%fr0,0(%1)" : "=m" (s.fpreg) : "r" (&s.fpreg) : "%r0");
 134   unsigned int old_halfreg0 = s.halfreg[0];
 135   /* Clear all the relevant bits. */
 136   s.halfreg[0] &= ~ ((unsigned int) exceptions << 27);
 137   if (s.halfreg[0] != old_halfreg0)
 138     {
 139       /* Store the new status word.  */
 140       __asm__ __volatile__ ("fldd 0(%0),%%fr0" : : "r" (&s.fpreg), "m" (s.fpreg) : "%r0");
 141     }
 142
 143   return 0;
 144 }
 145
 146 # elif defined __ia64__
 147
 148 int
 149 feclearexcept (int exceptions)
 150 {
 151   exceptions &= FE_ALL_EXCEPT;
 152
 153   unsigned long fpsr, orig_fpsr;
 154   _FPU_GETCW (orig_fpsr);
 155   fpsr = orig_fpsr & ~ (unsigned long) (exceptions << 13);
 156   if (fpsr != orig_fpsr)
 157     _FPU_SETCW (fpsr);
 158
 159   return 0;
 160 }
 161
 162 # elif defined __m68k__
 163
 164 int
 165 feclearexcept (int exceptions)
 166 {
 167   exceptions &= FE_ALL_EXCEPT;
 168
 169   unsigned int fpsr, orig_fpsr;
 170   _FPU_GETFPSR (orig_fpsr);
 171   fpsr = orig_fpsr & ~ exceptions;
 172   if (fpsr != orig_fpsr)
 173     _FPU_SETFPSR (fpsr);
 174
 175   return 0;
 176 }
 177
 178 # elif defined __mips__
 179
 180 int
 181 feclearexcept (int exceptions)
 182 {
 183   exceptions &= FE_ALL_EXCEPT;
 184
 185   /* Clear also the cause bits.  If the cause bit is not cleared, the next
 186      CTC instruction (just below) will re-generate the exception.  */
 187   unsigned int fcsr, orig_fcsr;
 188   _FPU_GETCW (orig_fcsr);
 189   fcsr = orig_fcsr & ~ ((exceptions << 10) | exceptions);
 190   if (fcsr != orig_fcsr)
 191     _FPU_SETCW (fcsr);
 192
 193   return 0;
 194 }
 195
 196 # elif defined __loongarch__
 197
 198 int
 199 feclearexcept (int exceptions)
 200 {
 201   exceptions &= FE_ALL_EXCEPT;
 202
 203   /* Clear also the cause bits.  If the cause bit is not cleared, the next
 204      CTC instruction (just below) will re-generate the exception.  */
 205   unsigned int fcsr, orig_fcsr;
 206   _FPU_GETCW (orig_fcsr);
 207   fcsr = orig_fcsr & ~ ((exceptions << 8) | exceptions);
 208   if (fcsr != orig_fcsr)
 209     _FPU_SETCW (fcsr);
 210
 211   return 0;
 212 }
 213
 214 # elif defined __powerpc__
 215
 216 int
 217 feclearexcept (int exceptions)
 218 {
 219   exceptions &= FE_ALL_EXCEPT;
 220
 221   union { unsigned long long u; double f; } memenv, orig_memenv;
 222   _FPU_GETCW_AS_DOUBLE (memenv.f);
 223   orig_memenv = memenv;
 224
 225   /* Instead of clearing FE_INVALID (= bit 29), we need to clear the
 226      individual bits.  */
 227   memenv.u &= ~ (exceptions & FE_INVALID
 228                  ? (exceptions & ~FE_INVALID) | 0x01F80700U
 229                  : exceptions);
 230
 231   if (!(memenv.u == orig_memenv.u))
 232     _FPU_SETCW_AS_DOUBLE (memenv.f);
 233
 234   return 0;
 235 }
 236
 237 # elif defined __riscv
 238
 239 int
 240 feclearexcept (int exceptions)
 241 {
 242   exceptions &= FE_ALL_EXCEPT;
 243   __asm__ __volatile__ ("csrc fflags, %0" : : "r" (exceptions));
 244   return 0;
 245 }
 246
 247 # elif defined __s390__ || defined __s390x__
 248
 249 int
 250 feclearexcept (int exceptions)
 251 {
 252   exceptions &= FE_ALL_EXCEPT;
 253
 254   unsigned int fpc, orig_fpc;
 255   _FPU_GETCW (orig_fpc);
 256 #  if FE_INEXACT == 8 /* glibc compatible FE_* values */
 257   fpc = orig_fpc & ~(exceptions << 16);
 258   if ((fpc & 0x00000300) == 0)
 259     fpc &= ~(exceptions << 8);
 260 #  else /* musl libc compatible FE_* values */
 261   fpc = orig_fpc & ~exceptions;
 262   if ((fpc & 0x00000300) == 0)
 263     fpc &= ~(exceptions >> 8);
 264 #  endif
 265   if (fpc != orig_fpc)
 266     _FPU_SETCW (fpc);
 267
 268   return 0;
 269 }
 270
 271 # elif defined __sh__
 272
 273 int
 274 feclearexcept (int exceptions)
 275 {
 276   exceptions &= FE_ALL_EXCEPT;
 277
 278   unsigned int fpscr, orig_fpscr;
 279   _FPU_GETCW (orig_fpscr);
 280   fpscr = orig_fpscr & ~exceptions;
 281   if (fpscr != orig_fpscr)
 282     _FPU_SETCW (fpscr);
 283
 284   return 0;
 285 }
 286
 287 # elif defined __sparc
 288
 289 int
 290 feclearexcept (int exceptions)
 291 {
 292   exceptions &= FE_ALL_EXCEPT;
 293
 294   unsigned long fsr, orig_fsr;
 295   _FPU_GETCW (orig_fsr);
 296 #  if FE_INEXACT == 32 /* glibc compatible FE_* values */
 297   fsr = orig_fsr & ~exceptions;
 298 #  else /* Solaris compatible FE_* values */
 299   fsr = orig_fsr & ~(exceptions << 5);
 300 #  endif
 301   if (fsr != orig_fsr)
 302     _FPU_SETCW (fsr);
 303
 304   return 0;
 305 }
 306
 307 # else
 308
 309 #  if defined __GNUC__ || defined __clang__
 310 #   warning "Unknown CPU / architecture. Please report your platform and compiler to <bug-gnulib@gnu.org>."
 311 #  endif
 312 #  define NEED_FALLBACK 1
 313
 314 # endif
 315
 316 #else
 317
 318 /* The compiler does not support __asm__ statements or equivalent
 319    intrinsics.  */
 320
 321 # if HAVE_FPSETSTICKY
 322 /* FreeBSD ≥ 3.1, NetBSD ≥ 1.1, OpenBSD, IRIX, Solaris, Minix ≥ 3.2.  */
 323
 324 /* Get fpgetsticky, fpsetsticky.  */
 325 #  include <ieeefp.h>
 326 /* The type is called 'fp_except_t' on FreeBSD, but 'fp_except' on
 327    all other systems.  */
 328 #  if !defined __FreeBSD__
 329 #   define fp_except_t fp_except
 330 #  endif
 331
 332 int
 333 feclearexcept (int exceptions)
 334 {
 335   exceptions &= FE_ALL_EXCEPT;
 336
 337   fp_except_t flags, orig_flags;
 338   orig_flags = fpgetsticky ();
 339   flags = orig_flags & ~exceptions;
 340   if (flags != orig_flags)
 341     fpsetsticky (flags);
 342
 343   return 0;
 344 }
 345
 346 # elif defined _AIX && defined __powerpc__ /* AIX */
 347
 348 #  include <float.h>
 349 #  include <fpxcp.h>
 350
 351 /* Documentation:
 352    <https://www.ibm.com/docs/en/aix/7.3?topic=f-fp-clr-flag-fp-set-flag-fp-read-flag-fp-swap-flag-subroutine>  */
 353
 354 int
 355 feclearexcept (int exceptions)
 356 {
 357   exceptions &= FE_ALL_EXCEPT;
 358
 359   /* In addition to clearing FE_INVALID (= bit 29), we also need to clear the
 360      individual bits.  */
 361   fpflag_t f_to_clear =
 362     exceptions_to_fpflag (exceptions)
 363     | (exceptions & FE_INVALID ? 0x01F80700U : 0);
 364   if (f_to_clear != 0)
 365     fp_clr_flag (f_to_clear);
 366
 367   return 0;
 368 }
 369
 370 # else
 371
 372 #  define NEED_FALLBACK 1
 373
 374 # endif
 375
 376 #endif
 377
 378 #if NEED_FALLBACK
 379
 380 /* A dummy fallback.  */
 381
 382 int
 383 feclearexcept (int exceptions)
 384 {
 385   exceptions &= FE_ALL_EXCEPT;
 386   if (exceptions != 0)
 387     return -1;
 388   return 0;
 389 }
 390
 391 #endif