compiler/stdc/math/s_nearbyint.c

   1 /*-
   2  * Copyright (c) 2004 David Schultz <das@FreeBSD.ORG>
   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  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  */
  26
  27 __FBSDID("$FreeBSD: src/lib/msun/src/s_nearbyint.c,v 1.1 2004/07/06 04:46:08 das Exp $");
  28
  29 #include <fenv.h>
  30 #include <math.h>
  31
  32 /*
  33  * We save and restore the floating-point environment to avoid raising
  34  * an inexact exception.  We can get away with using fesetenv()
  35  * instead of feclearexcept()/feupdateenv() to restore the environment
  36  * because the only exception defined for rint() is overflow, and
  37  * rounding can't overflow as long as emax >= p.
  38  */
  39 #define DECL(type, fn, rint)    \
  40 type                            \
  41 fn(type x)                      \
  42 {                               \
  43         type ret;               \
  44         fenv_t env;             \
  45                                 \
  46         fegetenv(&env);         \
  47         ret = rint(x);          \
  48         fesetenv(&env);         \
  49         return (ret);           \
  50 }
  51
  52 DECL(double, nearbyint, rint)
  53 DECL(float, nearbyintf, rintf)