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5d1ccdda7b
The divss instruction clobbers its first argument, and the constraints need to reflect that. Fortunately, with GCC 12, generated code does not actually change, so there is no externally visible bug. Suggested-by: Jakub Jelinek <jakub@redhat.com> Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
122 lines
3.7 KiB
C
122 lines
3.7 KiB
C
/* Raise given exceptions.
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Copyright (C) 2001-2023 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <fenv.h>
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#include <math.h>
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int
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__feraiseexcept (int excepts)
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{
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/* Raise exceptions represented by EXPECTS. But we must raise only
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one signal at a time. It is important that if the overflow/underflow
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exception and the inexact exception are given at the same time,
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the overflow/underflow exception follows the inexact exception. */
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/* First: invalid exception. */
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if ((FE_INVALID & excepts) != 0)
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{
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/* One example of an invalid operation is 0.0 / 0.0. */
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float f = 0.0;
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__asm__ __volatile__ ("divss %0, %0 " : "+x" (f));
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(void) &f;
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}
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/* Next: division by zero. */
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if ((FE_DIVBYZERO & excepts) != 0)
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{
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float f = 1.0;
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float g = 0.0;
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__asm__ __volatile__ ("divss %1, %0" : "+x" (f) : "x" (g));
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(void) &f;
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}
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/* Next: overflow. */
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if ((FE_OVERFLOW & excepts) != 0)
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{
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/* XXX: Is it ok to only set the x87 FPU? */
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/* There is no way to raise only the overflow flag. Do it the
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hard way. */
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fenv_t temp;
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/* Bah, we have to clear selected exceptions. Since there is no
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`fldsw' instruction we have to do it the hard way. */
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__asm__ __volatile__ ("fnstenv %0" : "=m" (*&temp));
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/* Set the relevant bits. */
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temp.__status_word |= FE_OVERFLOW;
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/* Put the new data in effect. */
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__asm__ __volatile__ ("fldenv %0" : : "m" (*&temp));
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/* And raise the exception. */
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__asm__ __volatile__ ("fwait");
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}
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/* Next: underflow. */
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if ((FE_UNDERFLOW & excepts) != 0)
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{
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/* XXX: Is it ok to only set the x87 FPU? */
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/* There is no way to raise only the underflow flag. Do it the
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hard way. */
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fenv_t temp;
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/* Bah, we have to clear selected exceptions. Since there is no
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`fldsw' instruction we have to do it the hard way. */
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__asm__ __volatile__ ("fnstenv %0" : "=m" (*&temp));
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/* Set the relevant bits. */
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temp.__status_word |= FE_UNDERFLOW;
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/* Put the new data in effect. */
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__asm__ __volatile__ ("fldenv %0" : : "m" (*&temp));
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/* And raise the exception. */
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__asm__ __volatile__ ("fwait");
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}
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/* Last: inexact. */
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if ((FE_INEXACT & excepts) != 0)
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{
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/* XXX: Is it ok to only set the x87 FPU? */
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/* There is no way to raise only the inexact flag. Do it the
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hard way. */
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fenv_t temp;
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/* Bah, we have to clear selected exceptions. Since there is no
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`fldsw' instruction we have to do it the hard way. */
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__asm__ __volatile__ ("fnstenv %0" : "=m" (*&temp));
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/* Set the relevant bits. */
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temp.__status_word |= FE_INEXACT;
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/* Put the new data in effect. */
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__asm__ __volatile__ ("fldenv %0" : : "m" (*&temp));
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/* And raise the exception. */
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__asm__ __volatile__ ("fwait");
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}
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/* Success. */
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return 0;
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}
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libm_hidden_def (__feraiseexcept)
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weak_alias (__feraiseexcept, feraiseexcept)
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libm_hidden_weak (feraiseexcept)
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