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122 lines
3.7 KiB
C
122 lines
3.7 KiB
C
/* Raise given exceptions.
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Copyright (C) 2001-2020 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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