compiler/stdc/math/s_lrint.c

   1 /*-
   2  * Copyright (c) 2005 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 #include <fenv.h>
  28 #include <math.h>
  29
  30 #ifndef type
  31 __FBSDID("$FreeBSD: src/lib/msun/src/s_lrint.c,v 1.1 2005/01/11 23:12:55 das Exp $");
  32 #define type            double
  33 #define roundit         rint
  34 #define dtype           long
  35 #define fn              lrint
  36 #endif
  37
  38 /*
  39  * C99 says we should not raise a spurious inexact exception when an
  40  * invalid exception is raised.  Unfortunately, the set of inputs
  41  * that overflows depends on the rounding mode when 'dtype' has more
  42  * significant bits than 'type'.  Hence, we bend over backwards for the
  43  * sake of correctness; an MD implementation could be more efficient.
  44  */
  45 dtype
  46 fn(type x)
  47 {
  48         fenv_t env;
  49         dtype d;
  50
  51         feholdexcept(&env);
  52         d = (dtype)roundit(x);
  53         if (fetestexcept(FE_INVALID))
  54                 feclearexcept(FE_INEXACT);
  55         feupdateenv(&env);
  56         return (d);
  57 }