newlib/libm/machine/riscv/fesetexceptflag.c

   1 /*
   2   (c) Copyright 2017 Michael R. Neilly
   3   All rights reserved.
   4
   5   Redistribution and use in source and binary forms, with or without
   6   modification, are permitted provided that the following conditions
   7   are met:
   8
   9   * Redistributions of source code must retain the above copyright
  10   notice, this list of conditions and the following disclaimer.
  11
  12   * Redistributions in binary form must reproduce the above copyright
  13   notice, this list of conditions and the following disclaimer in the
  14   documentation and/or other materials provided with the distribution.
  15
  16   * Neither the names of the copyright holders nor the names of their
  17   contributors may be used to endorse or promote products derived from
  18   this software without specific prior written permission.
  19
  20   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  21   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  22   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  23   FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  24   COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  25   INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
  26   BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  27   LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  28   CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29   LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
  30   ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  31   POSSIBILITY OF SUCH DAMAGE.
  32 */
  33
  34 #include <fenv.h>
  35 #include "riscv_math.h"
  36
  37 /* This implementation is intended to comply with the following
  38  * specification:
  39  *
  40  * http://pubs.opengroup.org/onlinepubs/009695399/functions/fesetexceptflag.html
  41  * Referred to as 'fesetexceptflag.html below.
  42  *
  43  * "The fesetexceptflag() function shall attempt to set the
  44  * floating-point status flags indicated by the argument excepts to
  45  * the states stored in the object pointed to by flagp. The value
  46  * pointed to by flagp shall have been set by a previous call to
  47  * fegetexceptflag() whose second argument represented at least those
  48  * floating-point exceptions represented by the argument excepts. This
  49  * function does not raise floating-point exceptions, but only sets
  50  * the state of the flags."
  51  *
  52  */
  53
  54 int fesetexceptflag(const fexcept_t *flagp, int excepts)
  55 {
  56
  57 #ifdef __RISCV_HARD_FLOAT
  58
  59   /* Mask excepts to be sure only supported flag bits are set */
  60
  61   excepts &= FE_ALL_EXCEPT;
  62
  63   /* Set the requested flags */
  64
  65   fexcept_t fflags = (excepts & *flagp);
  66
  67   /* Set new the flags */
  68
  69   asm volatile("csrs fflags, %0" : : "r"(fflags));
  70
  71   /* Per 'fesetexceptflag.html:
  72    *
  73    * "If the excepts argument is zero or if all the specified
  74    * exceptions were successfully set, fesetexceptflag() shall return
  75    * zero. Otherwise, it shall return a non-zero value."
  76    */
  77
  78 #endif
  79
  80   return 0;
  81 }