compiler/mlib/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 <sys/cdefs.h>
  28 #include <fenv.h>
  29 #include <math.h>
  30
  31 #ifndef type
  32 __FBSDID("$FreeBSD: src/lib/msun/src/s_lrint.c,v 1.1 2005/01/11 23:12:55 das Exp $");
  33 #define type            double
  34 #define roundit         rint
  35 #define dtype           long
  36 #define fn              lrint
  37 #endif
  38
  39 /*
  40  * C99 says we should not raise a spurious inexact exception when an
  41  * invalid exception is raised.  Unfortunately, the set of inputs
  42  * that overflows depends on the rounding mode when 'dtype' has more
  43  * significant bits than 'type'.  Hence, we bend over backwards for the
  44  * sake of correctness; an MD implementation could be more efficient.
  45  */
  46 dtype
  47 fn(type x)
  48 {
  49         fenv_t env;
  50         dtype d;
  51
  52         feholdexcept(&env);
  53         d = (dtype)roundit(x);
  54         if (fetestexcept(FE_INVALID))
  55                 feclearexcept(FE_INEXACT);
  56         feupdateenv(&env);
  57         return (d);
  58 }