From: Dirk Herrmann <fight_spam@invalid.invalid>
Subject: Re: conversions between fixed-point types
Date: Sat, 19 Sep 2009 14:41:49 +0200
Date: 2009-09-19T14:41:49+02:00 [thread overview]
Message-ID: <h92jie$q4g$1@news.albasani.net> (raw)
In-Reply-To: <h90uf3$bdo$2@news.albasani.net>
Dirk Herrmann wrote:
> I am currently trying to learn about Ada's fixed-point types, and there
> are some points that I couldn't find any statement about, or which I
> simply could not understand.
And, while experimenting and trying out Adam Beneschan's solution for
rounding (thanks for your answer, Alan) I got totally confused because
of the following code (I am using GNAT 4.3.4 with the following
command line options: gnatmake -f -gnatVa -gnata -gnatwadhl.o
-save-temps conversion.adb): (For your convenience, I added the results
as comments within the code.)
with Ada.Text_IO;
procedure Conversion is
package TIO renames Ada.Text_IO;
package FIO is new Ada.Text_IO.Float_IO(Float);
type FpA is delta 0.5 range -10.0 .. +10.0; for FpA'Small use 0.5;
type FpB is delta 0.4 range -10.0 .. +10.0; for FpB'Small use 0.4;
function MakeB(F: in Float) return FpB is
begin
return FpB(F);
end MakeB;
function MakeBFromA(F: in FpA) return FpB is
begin
return FpB(F);
end MakeBFromA;
function MakeBViaA(F: in Float) return FpB is
begin
return FpB(FpA(F));
end MakeBViaA;
begin
FIO.Put(Float(FpA(-1.5))); TIO.Put(" "); --> -1.50000E+00
FIO.Put(Float(FpB(-1.5))); TIO.Put(" "); --> -1.20000E+00
FIO.Put(Float(FpB(Float(-1.5)))); TIO.Put(" "); --> -1.20000E+00
FIO.Put(Float(MakeB(-1.5))); TIO.Put(" "); --> -1.60000E+00
FIO.Put(Float(FpB(FpA(-1.5)))); TIO.Put(" "); --> -1.20000E+00
FIO.Put(Float(FpB(FpA(Float(-1.5))))); TIO.Put(" "); --> -1.20000E+00
FIO.Put(Float(MakeBFromA(FpA(-1.5)))); TIO.Put(" "); --> -1.60000E+00
FIO.Put(Float(MakeBViaA(-1.5))); TIO.Put(" "); --> -1.60000E+00
end Conversion;
Is this confusing behaviour allowed? I will submit a bug report if some
expert confirms it is a GNAT bug.
Thanks in advance,
Dirk Herrmann
(email address gladly given on request)
next prev parent reply other threads:[~2009-09-19 12:41 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-09-18 21:35 conversions between fixed-point types Dirk Herrmann
2009-09-18 22:42 ` Adam Beneschan
2009-09-19 12:41 ` Dirk Herrmann [this message]
2009-09-19 14:48 ` John B. Matthews
2009-09-20 8:15 ` Dirk Herrmann
2009-09-20 14:22 ` Robert A Duff
2009-09-20 18:55 ` Dirk Herrmann
2009-09-20 20:34 ` Simon Clubley
2009-09-23 20:46 ` Dirk Herrmann
2009-09-27 17:15 ` Simon Clubley
2009-09-27 19:22 ` sjw
2009-09-28 20:18 ` Dirk Herrmann
2009-09-28 18:37 ` Robert A Duff
2009-09-28 20:50 ` Dirk Herrmann
2009-09-20 15:18 ` John B. Matthews
2009-09-20 19:13 ` Dirk Herrmann
2009-09-20 20:09 ` tmoran
2009-09-21 17:24 ` Jeffrey R. Carter
2009-09-23 20:57 ` Dirk Herrmann
2009-09-23 22:28 ` Jeffrey R. Carter
2009-09-24 1:05 ` Adam Beneschan
2009-09-24 3:57 ` Jeffrey R. Carter
2009-09-25 8:47 ` Stuart
2009-09-25 20:41 ` sjw
2009-09-25 21:58 ` Jeffrey R. Carter
2009-09-28 13:40 ` Stuart
2009-09-26 14:43 ` Dirk Herrmann
2009-09-28 15:15 ` Adam Beneschan
2009-09-26 14:31 ` Dirk Herrmann
2009-09-19 18:38 ` tmoran
2009-09-20 8:22 ` sjw
replies disabled
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox