newlib/libm/common/s_isnand.c

   1 /*
   2  * ====================================================
   3  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
   4  *
   5  * Developed at SunPro, a Sun Microsystems, Inc. business.
   6  * Permission to use, copy, modify, and distribute this
   7  * software is freely granted, provided that this notice
   8  * is preserved.
   9  * ====================================================
  10  */
  11
  12 /*
  13 FUNCTION
  14         <<isnan>>, <<isnanf>>, <<isinf>>, <<isinff>>, <<finite>>, <<finitef>>---test for exceptional numbers
  15
  16 INDEX
  17         isnan
  18 INDEX
  19         isinf
  20 INDEX
  21         finite
  22
  23 INDEX
  24         isnanf
  25 INDEX
  26         isinff
  27 INDEX
  28         finitef
  29
  30 SYNOPSIS
  31         #include <math.h>
  32         int isnan(double <[arg]>);
  33         int isinf(double <[arg]>);
  34         int finite(double <[arg]>);
  35         int isnanf(float <[arg]>);
  36         int isinff(float <[arg]>);
  37         int finitef(float <[arg]>);
  38
  39
  40 DESCRIPTION
  41         These functions provide information on the floating-point
  42         argument supplied.
  43
  44         There are five major number formats:
  45         o+
  46         o zero
  47           A number which contains all zero bits.
  48         o subnormal
  49           A number with a zero exponent but a nonzero fraction.
  50         o normal
  51           A number with an exponent and a fraction.
  52         o infinity
  53           A number with an all 1's exponent and a zero fraction.
  54         o NAN
  55           A number with an all 1's exponent and a nonzero fraction.
  56
  57         o-
  58
  59         <<isnan>> returns 1 if the argument is a nan. <<isinf>>
  60         returns 1 if the argument is infinity.  <<finite>> returns 1 if the
  61         argument is zero, subnormal or normal.
  62
  63         Note that by the C99 standard, <<isnan>> and <<isinf>> are macros
  64         taking any type of floating-point and are declared in
  65         <<math.h>>.  Newlib has chosen to declare these both as functions
  66         and as macros in <<math.h>>.
  67
  68         The <<isnanf>>, <<isinff>> and <<finitef>> functions perform the same
  69         operations as their <<isnan>>, <<isinf>> and <<finite>>
  70         counterparts, but on single-precision floating-point numbers.
  71
  72 QUICKREF
  73         isnan - pure
  74 QUICKREF
  75         isinf - pure
  76 QUICKREF
  77         finite - pure
  78 QUICKREF
  79         isnan - pure
  80 QUICKREF
  81         isinf - pure
  82 QUICKREF
  83         finite - pure
  84 */
  85
  86 /*
  87  * __isnand(x) returns 1 is x is nan, else 0;
  88  * no branching!
  89  */
  90
  91 #include "fdlibm.h"
  92
  93 #ifndef _DOUBLE_IS_32BITS
  94
  95 int
  96 __isnand (double x)
  97 {
  98         __int32_t hx,lx;
  99         EXTRACT_WORDS(hx,lx,x);
 100         hx &= 0x7fffffff;
 101         hx |= (__uint32_t)(lx|(-lx))>>31;
 102         hx = 0x7ff00000 - hx;
 103         return (int)(((__uint32_t)(hx))>>31);
 104 }
 105
 106 #endif /* _DOUBLE_IS_32BITS */