toolchain/gcc/newlib/libm/math/w_sqrt.c

   1
   2 /* @(#)w_sqrt.c 5.1 93/09/24 */
   3 /*
   4  * ====================================================
   5  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
   6  *
   7  * Developed at SunPro, a Sun Microsystems, Inc. business.
   8  * Permission to use, copy, modify, and distribute this
   9  * software is freely granted, provided that this notice
  10  * is preserved.
  11  * ====================================================
  12  */
  13
  14 /*
  15 FUNCTION
  16         <<sqrt>>, <<sqrtf>>---positive square root
  17
  18 INDEX
  19         sqrt
  20 INDEX
  21         sqrtf
  22
  23 ANSI_SYNOPSIS
  24         #include <math.h>
  25         double sqrt(double <[x]>);
  26         float  sqrtf(float <[x]>);
  27
  28 TRAD_SYNOPSIS
  29         #include <math.h>
  30         double sqrt(<[x]>);
  31         float  sqrtf(<[x]>);
  32
  33 DESCRIPTION
  34         <<sqrt>> computes the positive square root of the argument.
  35         You can modify error handling for this function with
  36         <<matherr>>.
  37
  38 RETURNS
  39         On success, the square root is returned. If <[x]> is real and
  40         positive, then the result is positive.  If <[x]> is real and
  41         negative, the global value <<errno>> is set to <<EDOM>> (domain error).
  42
  43
  44 PORTABILITY
  45         <<sqrt>> is ANSI C.  <<sqrtf>> is an extension.
  46 */
  47
  48 /*
  49  * wrapper sqrt(x)
  50  */
  51
  52 #include "fdlibm.h"
  53 #include <errno.h>
  54
  55 #ifndef _DOUBLE_IS_32BITS
  56
  57 #ifdef __STDC__
  58         double sqrt(double x)           /* wrapper sqrt */
  59 #else
  60         double sqrt(x)                  /* wrapper sqrt */
  61         double x;
  62 #endif
  63 {
  64 #ifdef _IEEE_LIBM
  65         return __ieee754_sqrt(x);
  66 #else
  67         struct exception exc;
  68         double z;
  69         z = __ieee754_sqrt(x);
  70         if(_LIB_VERSION == _IEEE_ || isnan(x)) return z;
  71         if(x<0.0) {
  72           exc.type = DOMAIN;
  73           exc.name = "sqrt";
  74           exc.err = 0;
  75           exc.arg1 = exc.arg2 = x;
  76           if (_LIB_VERSION == _SVID_)
  77             exc.retval = 0.0;
  78           else
  79             exc.retval = 0.0/0.0;
  80           if (_LIB_VERSION == _POSIX_)
  81             errno = EDOM;
  82           else if (!matherr(&exc)) {
  83             errno = EDOM;
  84           }
  85           if (exc.err != 0)
  86             errno = exc.err;
  87           return exc.retval;
  88         } else
  89             return z;
  90 #endif
  91 }
  92
  93 #endif /* defined(_DOUBLE_IS_32BITS) */