lib/libm/src/s_nearbyint.c

   1 /*      $NetBSD: s_nearbyint.c,v 1.3 2013/02/11 02:45:27 christos Exp $ */
   2
   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 #if 0
  31 __FBSDID("$FreeBSD: src/lib/msun/src/s_nearbyint.c,v 1.2 2008/01/14 02:12:06 das Exp $");
  32 #else
  33 __RCSID("$NetBSD: s_nearbyint.c,v 1.3 2013/02/11 02:45:27 christos Exp $");
  34 #endif
  35
  36 #include <machine/ieee.h>
  37 #include <fenv.h>
  38 #include <math.h>
  39
  40 /*
  41  * We save and restore the floating-point environment to avoid raising
  42  * an inexact exception.  We can get away with using fesetenv()
  43  * instead of feclearexcept()/feupdateenv() to restore the environment
  44  * because the only exception defined for rint() is overflow, and
  45  * rounding can't overflow as long as emax >= p.
  46  */
  47 #define DECL(type, fn, rint)    \
  48 type                            \
  49 fn(type x)                      \
  50 {                               \
  51         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)
  62 #ifdef __HAVE_LONG_DOUBLE
  63 DECL(long double, nearbyintl, rintl)
  64 #endif