Re: precise floats

[radke@dsdl.ee.iastate.edu (Kevin Radke)]

In article <dewar.902579704@merv>, Robert Dewar <dewar@merv.cs.nyu.edu> wrote:
>Paul said
...
>This type then is most definitely covered by the requirement in B.2(10),
>and for an x86 implementation, must be defined in Interfaces. The relevant
>definitions from the GNAT version of Interfaces are
>
>   type IEEE_Float_32       is new Short_Float;
>   pragma Float_Representation (IEEE_Float, IEEE_Float_32);
>
>   type IEEE_Float_64       is new Long_Float;
>   pragma Float_Representation (IEEE_Float, IEEE_Float_64);
>
>   type IEEE_Extended_Float is new Long_Long_Float;
>   pragma Float_Representation (IEEE_Float, IEEE_Extended_Float);
...
>Note that I have no idea what other Ada compilers do here. All I know is
>that the standard mandates the inclusion of the 80-bit format in the
>Interfaces definition for a conforming Ada 95 compiler for the x86.
>We have already seen that people can get confused when they tell us
>what is and what is not in some particular compiler. So you should check
>for yourself to make sure that your compiler meets this requirement. It
>is indeed a requirement that should be checked by the validation suite,
>but in practice this kind of checking is hard. You can parametrize the
>validation suite by specifying the maximum fpt precision, but it is 
>difficult to check that this parametrization is done correctly when
>it is machine dependent.

It appears Apex 1.0.2b and Green Hills AdaMulti 1.8.8e (both
Windows NT native targets) fail to provide an IEEE_Extended_Float
as well. (I don't think this Apex version claims validation,
however I could be wrong.)

Kevin