compiler/stdc/math/s_lround.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 <limits.h>
  28 #include <fenv.h>
  29 #include <math.h>
  30
  31 #ifndef type
  32 __FBSDID("$FreeBSD: src/lib/msun/src/s_lround.c,v 1.2 2005/04/08 00:52:16 das Exp $");
  33 #define type            double
  34 #define roundit         round
  35 #define dtype           long
  36 #define DTYPE_MIN       LONG_MIN
  37 #define DTYPE_MAX       LONG_MAX
  38 #define fn              lround
  39 #endif
  40
  41 /*
  42  * If type has more precision than dtype, the endpoints dtype_(min|max) are
  43  * of the form xxx.5; they are "out of range" because lround() rounds away
  44  * from 0.  On the other hand, if type has less precision than dtype, then
  45  * all values that are out of range are integral, so we might as well assume
  46  * that everything is in range.  At compile time, INRANGE(x) should reduce to
  47  * two floating-point comparisons in the former case, or TRUE otherwise.
  48  */
  49 static const type dtype_min = DTYPE_MIN - 0.5;
  50 static const type dtype_max = DTYPE_MAX + 0.5;
  51 #define INRANGE(x)      (dtype_max - DTYPE_MAX != 0.5 || \
  52                          ((x) > dtype_min && (x) < dtype_max))
  53
  54 dtype
  55 fn(type x)
  56 {
  57
  58         if (INRANGE(x)) {
  59                 x = roundit(x);
  60                 return ((dtype)x);
  61         } else {
  62                 feraiseexcept(FE_INVALID);
  63                 return (DTYPE_MAX);
  64         }
  65 }