usr/src/lib/libc/port/fp/finite.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 /*      Copyright (c) 1988 AT&T */
  28 /*        All Rights Reserved   */
  29
  30 #pragma ident   "%Z%%M% %I%     %E% SMI"
  31
  32 /*      IEEE recommended functions */
  33
  34 #pragma weak _finite = finite
  35 #pragma weak _fpclass = fpclass
  36 #pragma weak _unordered = unordered
  37
  38 #include "lint.h"
  39 #include <values.h>
  40 #include "fpparts.h"
  41
  42 #define P754_NOFAULT 1          /* avoid generating extra code */
  43 #include <ieeefp.h>
  44
  45 /*
  46  * FINITE(X)
  47  * finite(x) returns 1 if x > -inf and x < +inf and 0 otherwise
  48  * NaN returns 0
  49  */
  50
  51 int
  52 finite(double x)
  53 {
  54         return ((EXPONENT(x) != MAXEXP));
  55 }
  56
  57 /*
  58  * UNORDERED(x,y)
  59  * unordered(x,y) returns 1 if x is unordered with y, otherwise
  60  * it returns 0; x is unordered with y if either x or y is NAN
  61  */
  62
  63 int
  64 unordered(double x, double y)
  65 {
  66         if ((EXPONENT(x) == MAXEXP) && (HIFRACTION(x) || LOFRACTION(x)))
  67                 return (1);
  68         if ((EXPONENT(y) == MAXEXP) && (HIFRACTION(y) || LOFRACTION(y)))
  69                 return (1);
  70         return (0);
  71 }
  72
  73 /*
  74  * FPCLASS(X)
  75  * fpclass(x) returns the floating point class x belongs to
  76  */
  77
  78 fpclass_t
  79 fpclass(double x)
  80 {
  81         int     sign, exp;
  82
  83         exp = EXPONENT(x);
  84         sign = SIGNBIT(x);
  85         if (exp == 0) { /* de-normal or zero */
  86                 if (HIFRACTION(x) || LOFRACTION(x)) /* de-normal */
  87                         return (sign ? FP_NDENORM : FP_PDENORM);
  88                 else
  89                         return (sign ? FP_NZERO : FP_PZERO);
  90         }
  91         if (exp == MAXEXP) { /* infinity or NaN */
  92                 if ((HIFRACTION(x) == 0) && (LOFRACTION(x) == 0)) /* infinity */
  93                         return (sign ? FP_NINF : FP_PINF);
  94                 else
  95                         if (QNANBIT(x))
  96                         /* hi-bit of mantissa set - quiet nan */
  97                                 return (FP_QNAN);
  98                         else    return (FP_SNAN);
  99         }
 100         /* if we reach here we have non-zero normalized number */
 101         return (sign ? FP_NNORM : FP_PNORM);
 102 }