modules/fdlibm/src/s_nearbyint.cpp

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
   3  *
   4  * Copyright (c) 2004 David Schultz <das@FreeBSD.ORG>
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. 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  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  */
  28
  29 //#include <sys/cdefs.h>
  30 //__FBSDID("$FreeBSD$");
  31
  32 #include <fenv.h>
  33
  34 #include "math_private.h"
  35
  36 /*
  37  * We save and restore the floating-point environment to avoid raising
  38  * an inexact exception.  We can get away with using fesetenv()
  39  * instead of feclearexcept()/feupdateenv() to restore the environment
  40  * because the only exception defined for rint() is overflow, and
  41  * rounding can't overflow as long as emax >= p.
  42  *
  43  * The volatile keyword is needed below because clang incorrectly assumes
  44  * that rint won't raise any floating-point exceptions. Declaring ret volatile
  45  * is sufficient to trick the compiler into doing the right thing.
  46  */
  47 #define DECL(type, fn, rint)    \
  48 type                            \
  49 fn(type x)                      \
  50 {                               \
  51         volatile type ret;      \
  52         fenv_t env;             \
  53                                 \
  54         fegetenv(&env);         \
  55         ret = rint(x);          \
  56         fesetenv(&env);         \
  57         return (ret);           \
  58 }
  59
  60 DECL(double, nearbyint, rint)
  61 DECL(float, nearbyintf, rintf)