Re: Another question about fixed point types.

["Yannick Duchêne (Hibou57)" <yannick_duchene@yahoo.fr>]

Le Sun, 29 Aug 2010 00:45:16 +0200, Peter C. Chapin <chapinp@acm.org> a  
écrit:
> That range does not include zero. However, the
> code above compiles and runs fine using GNAT GPL 2010.
I have never used fixed point type in Ada (nor floats by the way, but will  
do in the future for sound synthesis).
However, I had a look at the reference, and here is what it says which may  
be relevant in your area:

ARM 2005 - 3.5.9 Fixed Point Types - says:

    12{base range (of a fixed point type) [partial]} The base range (see  
3.5)
    of a fixed point type is symmetric around zero, except possibly for an  
extra
    negative value in some implementations.

If it is symmetric around zero, that should explain your observations, as  
I would be very surprised if there would be provision for a hole  
somewhere. If it is symmetric around zero, and there is no two disjoint  
range, then this is include zero.

A tiny test program which would write first and last of the base type may  
tell more.

Hint: note the “possibly for an extra negative value in some  
implementations”, which may be important for you as you seems to require  
deep understanding of what's going on.

> P.S. The code above is a simplification of the real code, but I believe
> it illustrates the question I have.
Yes, it seems it illustrates fine.

-- 
“Dual licensing is the Perl's way to disinfect the GNU General Public  
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