lib/libm/src/s_fmax.c

   1 /*      $OpenBSD: s_fmax.c,v 1.8 2013/03/28 18:09:38 martynas Exp $     */
   2 /*-
   3  * Copyright (c) 2004 David Schultz <das@FreeBSD.ORG>
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  25  * SUCH DAMAGE.
  26  */
  27
  28 #include <float.h>
  29 #include <math.h>
  30
  31 double
  32 fmax(double x, double y)
  33 {
  34         /* Check for NaNs to avoid raising spurious exceptions. */
  35         if (isnan(x))
  36                 return (y);
  37         if (isnan(y))
  38                 return (x);
  39
  40         /* Handle comparisons of signed zeroes. */
  41         if (signbit(x) != signbit(y)) {
  42                 if (signbit(x))
  43                         return (y);
  44                 else
  45                         return (x);
  46         }
  47
  48         return (x > y ? x : y);
  49 }
  50
  51 #if     LDBL_MANT_DIG == 53
  52 __strong_alias(fmaxl, fmax);
  53 #endif  /* LDBL_MANT_DIG == 53 */