From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Subject: Re: Fixed point constants issue
Date: Mon, 13 Sep 2010 20:04:32 +0200
Date: 2010-09-13T20:04:31+02:00 [thread overview]
Message-ID: <1f0l0baynq1x7$.phl9cqpwcr37.dlg@40tude.net> (raw)
In-Reply-To: op.vizer4qnd20q5n@jellix.jlfencey.com
On Mon, 13 Sep 2010 19:27:30 +0200, Vinzent Hoefler wrote:
> Is this a GNAT bug or am I just stupid?
>
> Suppose we have a fixed point type (with a rather large delta):
>
> -- 8< --
> with Ada.Text_IO; use Ada.Text_IO;
>
> procedure Fixed_Point
> is
> FEET_PER_METER : constant := 0.3048;
> HEIGHT : constant := 10; -- Feet
>
> type Altitude is delta (2.0**15 / 50_000.0) range 0.0 .. 50_000.0;
[...]
> Can anyone shed some light on this? This has driven us crazy for weeks now.
>
> [1] Of course, "Altitude'(HEIGHT * FEET_PER_METER)" yields "0.0" again.
> At least this is consistent with my understanding so far.
Hmm, what did you expect? 0.3048 (FEET_PER_METER) is 0 when Altitude. That
is because 2.0**15/50_000.0=0.65536 > 0.3048.
--
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de
next prev parent reply other threads:[~2010-09-13 18:04 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-13 17:27 Fixed point constants issue Vinzent Hoefler
2010-09-13 18:04 ` Dmitry A. Kazakov [this message]
2010-09-13 18:25 ` Vinzent Hoefler
2010-09-13 19:05 ` Niklas Holsti
2010-09-13 20:35 ` Vinzent Hoefler
2010-09-13 20:35 ` Jeffrey Carter
2010-09-13 21:06 ` Vinzent Hoefler
2010-09-14 5:39 ` Niklas Holsti
2010-09-24 14:43 ` Markus Schöpflin
2010-09-24 20:05 ` Vinzent Hoefler
2010-09-24 21:38 ` Jeffrey Carter
2010-09-24 22:42 ` Vinzent Hoefler
2010-09-25 0:16 ` Jeffrey Carter
2010-09-27 10:33 ` Markus Schöpflin
2010-09-27 18:57 ` Jeffrey Carter
2010-09-28 8:16 ` Markus Schöpflin
2010-09-28 17:28 ` Jeffrey Carter
2010-10-05 6:27 ` Randy Brukardt
2010-10-05 18:40 ` Jeffrey Carter
2010-09-27 17:58 ` Adam Beneschan
2010-09-13 20:32 ` Dmitry A. Kazakov
2010-09-13 21:08 ` Vinzent Hoefler
2010-09-14 6:54 ` J-P. Rosen
2010-09-14 18:28 ` Vinzent Hoefler
2010-09-14 7:47 ` Dmitry A. Kazakov
2010-09-14 17:42 ` Vinzent Hoefler
2010-09-15 8:35 ` Dmitry A. Kazakov
2010-09-15 17:24 ` Vinzent Hoefler
2010-09-15 20:11 ` Dmitry A. Kazakov
2010-09-14 19:44 ` Keith Thompson
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