NAME

Math::Float128 - perl interface to C's __float128 operations

BUGS

  1) exp() segfaults with Strawberry Perl's 32-bit and 64-bit MinGW
     compilers.
  2) Needs quadmath.h in order to build.

DESCRIPTION

   use Math::Float128 qw(:all);

   my $arg = 32.1;
   my $f1 = Math::Float128->new($arg);# Stringify $arg, then assign 
                                          # using C's strtoflt128()
   my $f2 = NVtoF128($arg); # Assign the NV 32.1 to $f2.

OVERLOADING

   The following operations are overloaded:
    + - * / **
    += -= *= /= **=
    != == <= >= <=> < >
    ++ --
    =
    abs bool ! int print
    sqrt log exp
    sin cos atan2

    Arguments to the overloaded operations must be Math::Float128
    objects.

     $f = $f + 3.1; # currently an error. Do instead:

     $f = $f + Math::Float128->new('3.1');

ASSIGNMENT FUNCTIONS

   The following create and assign a new Math::Float128.

    $f = Math::Float128->new($arg);
     Returns a Math::Float128 object to which the numeric value of $arg
     has been assigned.
     If no arg is supplied then $f will be NaN.

    $f = UVtoF128($arg);
     Returns a Math::Float128 object to which the numeric (unsigned
     integer) value of $arg has been assigned.

    $f = IVtoF128($arg);
     Returns a Math::Float128 object to which the numeric (signed
     integer) value of $arg has been assigned.

    $f = NVtoF128($arg);
     Returns a Math::Float128 object to which the numeric (floating
     point) value of $arg has been assigned.

    $f2 = F128toF128($f1);
     Returns a Math::Float128 object that is a copy of the
     Math::Float128 object provided as the argument.
     Courtesy of overloading, this is in effect no different to doing:
     $f2 = $f1;

    $f = STRtoF128($str);
     Returns a Math::Float128 object that has the value of the string
     $str.

ASSIGNMENT OF INF, NAN, UNITY and ZERO

   $f = InfF128($sign);
    If $sign < 0, returns a Math::Float128 object set to
    negative infinity; else returns a Math::Float128 object set
    to positive infinity.

   $f = NaNF128($sign);
    If $sign < 0, returns a Math::Float128 object set to
    negative NaN; else returns a Math::Float128 object set to
    positive NaN. It may be problematical as to whether a NaN
    with the correct sign has been returned ... but, either way,
    it should return a NaN.

   $f = ZeroF128($sign);
    If $sign < 0, returns a Math::Float128 object set to
    negative zero; else returns a Math::Float128 object set to 
    zero.

   $f = UnityF128($sign);
    If $sign < 0, returns a Math::Float128 object set to
    negative one; else returns a Math::Float128 object set to 
    one.

   flt128_set_prec($precision);
    Sets the precision of stringified values to $precision decimal
    digits.

   $precision = flt128_get_prec();
    Returns the precision (in decimal digits) that will be used
    when stringifying values (by printing them, or calling
    F128toSTR).

RETRIEVAL FUNCTIONS

   The following functions provide ways of seeing the value of
   Math::Float128 objects.

   $nv = F128toNV($f);
    This function returns the value of the Math::Float128 object to
    a perl scalar (NV). It may not translate the value accurately.

   $string = F128toSTR($f);
    Returns the value of the Math::Float128 object as a string.
    The returned string will contain the same as is displayed by
    "print $f", except that print() will strip the trailing zeroes
    in the mantissa (significand) whereas F128toSTR won't.
    By default, provides 33 decimal digits of precision. This can be
    altered by specifying the desired precision (in decimal digits)
    in a call to flt128_set_prec.

   $string = F128toSTRP(f, $precision);
    Same as F128toSTR, but takes an additional arg that specifies the
    precision (in decimal digits) of the stringified return value.

OTHER FUNCTIONS

   $bool = is_NaNF128($f); 
    Returns 1 if $f is a Math::Float128 NaN.
    Else returns 0

   $int = is_InfF128($f)
    If the Math::Float128 object $f is -inf, returns -1.
    If it is +inf, returns 1.
    Otherwise returns 0.

   $int = is_ZeroF128($f);
    If the Math::Float128 object $f is -0, returns -1.
    If it is zero, returns 1.
    Otherwise returns 0.

   $int = cmp2NV($f, $nv);
    $nv can be any perl number - ie NV, UV or IV.
    If the Math::Float128 object $f < $nv returns -1.
    If it is > $nv, returns 1.
    Otherwise returns 0.

BUGS

   The mingw64 compilers have a buggy expq() function; therefore the
   overloaded exp function doesn't return expq($arg) when a mingw64
   compiler is in use - instead it returns e**$arg.

LICENSE

   This program is free software; you may redistribute it and/or modify
   it under the same terms as Perl itself.
   Copyright 2013 Sisyphus

AUTHOR

   Sisyphus <sisyphus at(@) cpan dot (.) org>