Re: Question about ordinary fixed point types.

[Robert A Duff <bobduff@shell01.TheWorld.com>]

"Peter C. Chapin" <chapinp@acm.org> writes:

> I don't think I'm too concerned about the actual value of Small used. In
> fact, I'd like to let the compiler choose so that it can optimize the
> code better. Isn't it the case that using a power of two allows for more
> efficient code generation for certain mathematical operations? I'm not
> sure, but I seem to recall reading that somewhere. If that is true, then
> I want that. My machine isn't very fast.

I'd expect "*" and "/" to be faster for binary smalls,
but I don't think it makes any difference for "+" and "-".
Multiplying angles by angles doesn't make much sense...

> My original question wasn't about how to force the type to use a Small
> that I want, rather it was about how can I be sure to visit every value
> of the type in a loop for test purposes.

You can test your test.  That is, write the loop using the
advice elsewhere in this thread, and unchecked-convert
each value to an integer of the same size, and see if
you get the integer representations you are expecting.

By the way, Ada.Numerics.Pi has at least 51 digits.

- Bob