[avr-libc-dev] Thanq for giving solution

[divya kanneganti]

Thanq u i am clarified



On Mon, Jan 5, 2009 at 10:31 PM, <address@hidden> wrote:

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> Today's Topics:
>
>   1. RE: bug in rand()/random()/do_rand()/do_random( ) (Mikal Hart)
>   2. RE: bug in rand()/random()/do_rand()/do_random( )
>      (Weddington, Eric)
>   3. RE: bug in rand()/random()/do_rand()/do_random( ) (Mikal Hart)
>   4. RE: bug in rand()/random()/do_rand()/do_random( )
>      (Weddington, Eric)
>   5. RE: bug in rand()/random()/do_rand()/do_random( ) (Mikal Hart)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Sun, 4 Jan 2009 18:37:53 -0600
> From: "Mikal Hart" <address@hidden>
> Subject: RE: [avr-libc-dev] bug in
>        rand()/random()/do_rand()/do_random( )
> To: "'Weddington, Eric'" <address@hidden>,   "'Joerg Wunsch'"
>        <address@hidden>,       <address@hidden>
> Message-ID: <address@hidden>
> Content-Type: text/plain;       charset="us-ascii"
>
> Thanks much for the quick replies, Joerg and Eric,
>
> Not being a Linux user myself, I forwarded your follow up questions to the
> original thread and got some replies (see
> http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1227218077/52#52).
>
> The most informative reply came from "Veronica" who reports that she sees
> the failure with this configuration:
>
> Ubuntu 8.10 (Intrepid Ibex)
> avr-libc 1:1.6.2-1
> avr-gcc 1:4.3.0-2
> Maintainer: Ubuntu MOTU Developers
> Linux main 2.6.27-11-generic #1 SMP Fri Dec 19 16:29:35 UTC 2008 x86_64
> GNU/Linux
>
> but when she installs the following files from debian sid, it fixes the
> problem:
>
> binutils-avr_2.18-4_amd64.deb
> avr-libc_1.6.2.cvs20080610-2_all.deb
> gcc-avr_4.3.2-1_amd64.deb
>
> Answering other specific points and questions:
>
> Eric, I understand that you should ordinarily seed to get reasonable
> randomness, but I intentionally avoided doing so in this case to better
> compare the behaviors of the varying implementations of rand() and random()
>
> Joerg, I agree that it is quite interesting that the very first number
> supplied by (unseeded) random() is 0.
>
> Does it seem like it's a problem with the 4.3.0 compiler?  Would you still
> recommend I file a bug report at savannah.nongnu.org?
>
> Regards,
>
> Mikal
>
> -----Original Message-----
> From: address@hidden
> [mailto:avr-libc-dev-bounces+mhcom <avr-libc-dev-bounces%2Bmhcom>=
> address@hidden On Behalf Of
> Weddington, Eric
> Sent: Saturday, January 03, 2009 5:41 PM
> To: Joerg Wunsch; address@hidden
> Subject: RE: [avr-libc-dev] bug in rand()/random()/do_rand()/do_random( )
>
>
>
> > -----Original Message-----
> > From:
> > address@hidden
> > [mailto:avr-libc-dev-bounces+eweddington<avr-libc-dev-bounces%2Beweddington>
> address@hidden
> > org] On Behalf Of Joerg Wunsch
> > Sent: Saturday, January 03, 2009 4:22 PM
> > To: address@hidden
> > Subject: Re: [avr-libc-dev] bug in
> > rand()/random()/do_rand()/do_random( )
> >
> > As Mikal Hart wrote:
> >
> >
> > That would also be an indication that the issue has been fixed long
> > since, but the Ubuntu users are apparently using a way old version of
> > avr-libc (probably since their package maintainer lags quite a couple
> > of years behind).
> >
>
> In the arduino forum thread, a user reported using Suse with avr-libc
> 1.6.1:
> <http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1227218077/15>
>
> So it's not a terribly old version.
>
>
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>
>
>
>
> ------------------------------
>
> Message: 2
> Date: Sun, 4 Jan 2009 19:47:15 -0700
> From: "Weddington, Eric" <address@hidden>
> Subject: RE: [avr-libc-dev] bug in
>        rand()/random()/do_rand()/do_random( )
> To: "Mikal Hart" <address@hidden>,   "Joerg Wunsch"
>        <address@hidden>, <address@hidden>
> Message-ID:
>        <address@hidden>
> Content-Type: text/plain;       charset="us-ascii"
>
>
>
> > -----Original Message-----
> > From: Mikal Hart [mailto:address@hidden
> > Sent: Sunday, January 04, 2009 5:38 PM
> > To: Weddington, Eric; 'Joerg Wunsch'; address@hidden
> > Subject: RE: [avr-libc-dev] bug in
> > rand()/random()/do_rand()/do_random( )
> >
> > Does it seem like it's a problem with the 4.3.0 compiler?
> > Would you still
> > recommend I file a bug report at savannah.nongnu.org?
>
> So far the evidence that you present points somehow to a problem with
> 4.3.0, since this user said it works with 4.3.2. There are known problems
> with 4.3.0 (for the AVR target) so I'm not totally surprised that 4.3.2
> would fix it.
>
> Because there are known problems with 4.3.0, I would not bother with filing
> a bug report with the avr-libc project, or the gcc project. But you just
> might be aware of this issue for the arduino community. Joerg and I do not
> frequent the arduino community forums or mailing lists.
>
> And perhaps in the future, it would be best if we could re-write rand(),
> random(), and do_rand() in assembly for avr-libc so this issue with the
> compiler won't happen again. ;-)
>
> Eric
>
>
>
>
> ------------------------------
>
> Message: 3
> Date: Sun, 4 Jan 2009 21:37:49 -0600
> From: "Mikal Hart" <address@hidden>
> Subject: RE: [avr-libc-dev] bug in
>        rand()/random()/do_rand()/do_random( )
> To: "'Weddington, Eric'" <address@hidden>,   "'Joerg Wunsch'"
>        <address@hidden>,       <address@hidden>
> Message-ID: <address@hidden>
> Content-Type: text/plain;       charset="us-ascii"
>
> > So far the evidence that you present points somehow to a problem with
> 4.3.0, since this user said it works with 4.3.2. There are known problems
> with 4.3.0 (for the AVR target) so I'm not totally surprised that 4.3.2
> would fix it.
>
> The only thing that makes me uneasy is that I don't see exactly where the
> defective compiler comes into play.  Perhaps it is just my lack of
> understanding of how things work in the Linux domain, but it seems to me
> that the bug must surely be in the avr-libc binary.  Is that binary being
> created with the system compiler?  My understanding (likely incorrect) was
> that Arduino users install a package that includes a precompiled avr-libc,
> in which case it would seem that the local compiler version would not come
> into direct play.  If, however, the avr-libc is indeed compiled as a part
> of
> the install process, then I see clearly how a problem compiler could be the
> culprit.
>
> Thanks for the guidance and keep up the good work! :)
>
> Regards,
>
> Mikal
>
> -----Original Message-----
> From: Weddington, Eric [mailto:address@hidden
> Sent: Sunday, January 04, 2009 8:47 PM
> To: Mikal Hart; Joerg Wunsch; address@hidden
> Subject: RE: [avr-libc-dev] bug in rand()/random()/do_rand()/do_random( )
>
>
>
> > -----Original Message-----
> > From: Mikal Hart [mailto:address@hidden
> > Sent: Sunday, January 04, 2009 5:38 PM
> > To: Weddington, Eric; 'Joerg Wunsch'; address@hidden
> > Subject: RE: [avr-libc-dev] bug in
> > rand()/random()/do_rand()/do_random( )
> >
> > Does it seem like it's a problem with the 4.3.0 compiler?
> > Would you still
> > recommend I file a bug report at savannah.nongnu.org?
>
> So far the evidence that you present points somehow to a problem with
> 4.3.0,
> since this user said it works with 4.3.2. There are known problems with
> 4.3.0 (for the AVR target) so I'm not totally surprised that 4.3.2 would
> fix
> it.
>
> Because there are known problems with 4.3.0, I would not bother with filing
> a bug report with the avr-libc project, or the gcc project. But you just
> might be aware of this issue for the arduino community. Joerg and I do not
> frequent the arduino community forums or mailing lists.
>
> And perhaps in the future, it would be best if we could re-write rand(),
> random(), and do_rand() in assembly for avr-libc so this issue with the
> compiler won't happen again. ;-)
>
> Eric
>
>
>
>
>
> ------------------------------
>
> Message: 4
> Date: Sun, 4 Jan 2009 21:00:43 -0700
> From: "Weddington, Eric" <address@hidden>
> Subject: RE: [avr-libc-dev] bug in
>        rand()/random()/do_rand()/do_random( )
> To: "Mikal Hart" <address@hidden>,   "Joerg Wunsch"
>        <address@hidden>, <address@hidden>
> Message-ID:
>        <address@hidden>
> Content-Type: text/plain;       charset="us-ascii"
>
>
>
> > -----Original Message-----
> > From: Mikal Hart [mailto:address@hidden
> > Sent: Sunday, January 04, 2009 8:38 PM
> > To: Weddington, Eric; 'Joerg Wunsch'; address@hidden
> > Subject: RE: [avr-libc-dev] bug in
> > rand()/random()/do_rand()/do_random( )
> >
> > > So far the evidence that you present points somehow to a
> > problem with
> > 4.3.0, since this user said it works with 4.3.2. There are
> > known problems
> > with 4.3.0 (for the AVR target) so I'm not totally surprised
> > that 4.3.2
> > would fix it.
> >
> > The only thing that makes me uneasy is that I don't see
> > exactly where the
> > defective compiler comes into play.
>
> Avr-libc is compiled with avr-gcc. The random functions in avr-libc are
> written in C, hence the generated code is dependent on the avr-gcc compiler.
> Avr-gcc 4.3.0 has code generation problems that are known. Avr-gcc 4.3.2
> fixes those code generation problems. So it is a matter of what version of
> avr-gcc was used to compile avr-libc.
>
> Is that any clearer?
>
>
>
>
> ------------------------------
>
> Message: 5
> Date: Sun, 4 Jan 2009 23:46:56 -0600
> From: "Mikal Hart" <address@hidden>
> Subject: RE: [avr-libc-dev] bug in
>        rand()/random()/do_rand()/do_random( )
> To: "'Weddington, Eric'" <address@hidden>,   "'Joerg Wunsch'"
>        <address@hidden>,       <address@hidden>
> Message-ID: <address@hidden>
> Content-Type: text/plain;       charset="us-ascii"
>
> I understand that avr-libc is compiled by avr-gcc and that a defective
> avr-gcc could possibly lead to a flawed copy of the library binary -- at
> least the stuff written in C like random().  But here's the thing.  When I
> install my Arduino package for Windows, I get a precompiled copy of
> avr-libc, so it (presumably) doesn't matter that the package also contains
> the bad compiler -- and in fact it does include the "bad" 4.3.0 version --
> I'm still getting the "good" library.  This is just speculation here, but
> I'm guessing that that means the Windows avr-libc must have been compiled
> with a different compiler (4.3.2?) than the one distributed alongside it
> (4.3.0) in the Arduino package.
>
> In Linux-land, the paradigm is different.  Unlike Windows, the Arduino
> Linux
> package doesn't supply either avr-gcc or avr-libc.  Instead, it requires
> the
> user to procure these from "elsewhere", and this leads to the problem we
> have been discussing.  Perhaps we need to change this to match Windows for
> consistency's sake if nothing else.
>
> Many thanks again for your replies and clear explanation.
>
> Mikal
>
>
>
> -----Original Message-----
> From: Weddington, Eric [mailto:address@hidden
> Sent: Sunday, January 04, 2009 10:01 PM
> To: Mikal Hart; Joerg Wunsch; address@hidden
> Subject: RE: [avr-libc-dev] bug in rand()/random()/do_rand()/do_random( )
>
>
>
> > -----Original Message-----
> > From: Mikal Hart [mailto:address@hidden
> > Sent: Sunday, January 04, 2009 8:38 PM
> > To: Weddington, Eric; 'Joerg Wunsch'; address@hidden
> > Subject: RE: [avr-libc-dev] bug in
> > rand()/random()/do_rand()/do_random( )
> >
> > > So far the evidence that you present points somehow to a
> > problem with
> > 4.3.0, since this user said it works with 4.3.2. There are
> > known problems
> > with 4.3.0 (for the AVR target) so I'm not totally surprised
> > that 4.3.2
> > would fix it.
> >
> > The only thing that makes me uneasy is that I don't see
> > exactly where the
> > defective compiler comes into play.
>
> Avr-libc is compiled with avr-gcc. The random functions in avr-libc are
> written in C, hence the generated code is dependent on the avr-gcc
> compiler.
> Avr-gcc 4.3.0 has code generation problems that are known. Avr-gcc 4.3.2
> fixes those code generation problems. So it is a matter of what version of
> avr-gcc was used to compile avr-libc.
>
> Is that any clearer?
>
>
>
>
>
> ------------------------------
>
> _______________________________________________
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> address@hidden
> http://lists.nongnu.org/mailman/listinfo/avr-libc-dev
>
>
> End of AVR-libc-dev Digest, Vol 74, Issue 2
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