90 lines
2.8 KiB
C
90 lines
2.8 KiB
C
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/*
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(c) Copyright 2017 Michael R. Neilly
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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are met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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* Neither the names of the copyright holders nor the names of their
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contributors may be used to endorse or promote products derived from
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this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <fenv.h>
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/* This implementation is intended to comply with the following
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* specification:
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*
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* http://pubs.opengroup.org/onlinepubs/9699919799/functions/feupdateenv.html
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*
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* "The feupdateenv() function shall attempt to save the currently
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* raised floating-point exceptions in its automatic storage, attempt
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* to install the floating-point environment represented by the object
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* pointed to by envp, and then attempt to raise the saved
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* floating-point exceptions. The argument envp shall point to an
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* object set by a call to feholdexcept() or fegetenv(), or equal a
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* floating-point environment macro."
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*/
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int feupdateenv(const fenv_t *envp)
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{
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#if __riscv_flen
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/* Get current exception flags */
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fexcept_t flags;
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asm volatile("frflags %0" : "=r"(flags));
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/* Set the environment as requested */
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fenv_t fcsr = *envp; /* Environment to install */
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asm volatile("fscsr %0" : : "r"(fcsr)); /* Install environment */
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/* OR in the saved exception flags */
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asm volatile("csrs fflags, %0" : : "r"(flags));
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/* "The feupdateenv() function shall return a zero value if and only
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* if all the required actions were successfully carried out."
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*/
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return 0;
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#else
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/* For soft float */
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#if defined FE_NOMASK_ENV && FE_ALL_EXCEPT != 0
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if (envp == FE_NOMASK_ENV)
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return 1;
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#endif
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return 0;
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#endif
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}
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