determining the next model number >= any arbitrary number

determining the next model number >= any arbitrary number

[Terry J. Westley]

Given the following:

	type PERCENTAGE is digits 6 range 0.0..110.0;

Since 100.0 cannot be exactly expressed in a binary floating point
representation (available on most modern machines), then the following
must yield a model number less than or greater than 100.0, never exactly
100.0.

	Complete : PERCENTAGE := 100.0;

I don't believe the RM says anything about which an implementation must
pick.

So, how can I guarantee that this assignment will always yield a value
greater than or equal to 100.0?

Maybe:

	Complete : PERCENTAGE := 100.0 + PERCENTAGE'small;

But, since 'small is so "small," I can't depend on this for any
arbitrary assignment, especially when the assigned value is
significantly larger than 'small.

What I really want is something more like the following:

	Complete : PERCENTAGE := 100.0 + PERCENTAGE'epsilon(100.0);

if only epsilon were defined to accept a parameter instead of simply
returning the size of the model number interval around 1.0.

Any ideas on how can this could be done?

--
-- 
Terry J. Westley
Arvin/Calspan Advanced Technology Center
P.O. Box 400, Buffalo, NY 14225
westley%planck.uucp@acsu.buffalo.edu

Re: determining the next model number >= any arbitrary number

[Robert Firth]

In article <1991Jan2.152418.11783@planck.uucp> westley%planck.uucp@acsu.buffalo.edu (Terry J. Westley) writes:

>Since 100.0 cannot be exactly expressed in a binary floating point
>representation

Sure can.  (sign => 0, exponent => 2#111#, mantissa => 2#0.11001#)