From: Christoph Grein <christoph.grein@eurocopter.com>
Subject: Re: Confused about Attribute Size?
Date: Tue, 22 Jan 2002 09:00:43 +0100 (MET)
Date: 2002-01-22T09:00:43+01:00 [thread overview]
Message-ID: <mailman.1011686522.29401.comp.lang.ada@ada.eu.org> (raw)
>
> type My_Type is
> (startbit,
> endbit,
> timeout,
> spare,
> nextbit,
> ......
> ......
> lastbit);
This assigns _values_ (not bit positions) to the enumeration literals that shall
be used to represent them internally, i.e. startbit has the value (or is another
name for) 0, lastbit the value 15. However you have no access to the internal
values (you can't add them e.g. startbit + timeout is illegal).
> for My_Type use
> (startbit =>0,
> endbit=>1,
> timeout=>2,
> spare=>3,
> nextbit=>4,
> ......
> ......
> lastbit=>15);
>
> for My_Type'Size use 8;
Since a value of 15 = 2#00001111# can be represented in 8 bits, there is no
problem.
> type My_Type_Array is array (My_Type) of Boolean;
>
> What I don't understand is how you can assign the size to 8 bits? How will
> this work when
> there are 16 bits in the type? What will be the size of the array?
> This example was in Ada 83 could this be a clue?
In Ada95, there is no need to explicitly define this default representation, see
RM 13.4(8).
next reply other threads:[~2002-01-22 8:00 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-01-22 8:00 Christoph Grein [this message]
-- strict thread matches above, loose matches on Subject: below --
2002-01-22 7:39 Confused about Attribute Size? Zebylon
2002-01-22 19:08 ` Patrick Hohmeyer
2002-01-22 22:56 ` Mark Johnson
2002-01-23 2:20 ` Jeffrey Carter
2002-01-23 14:56 ` Mark Johnson
2002-01-23 17:06 ` Jeffrey Carter
2002-01-24 4:11 ` Robert Dewar
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