Debian Bug report logs - #212570
libsdl-net1.2-dev: bad aligned access considerations on ARM

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Message #5 received at submit@bugs.debian.org (full text, mbox, reply):

From: Sam Hocevar <sam@zoy.org>

To: Debian Bug Tracking System <submit@bugs.debian.org>

Subject: libsdl-net1.2-dev: bad aligned access considerations on ARM

Date: Wed, 24 Sep 2003 15:31:22 +0200

Package: libsdl-net1.2-dev
Version: 1.2.5-2 (not installed)
Severity: important
Tags: upstream patch

   /usr/include/SDL/SDL_net.h has the following code:

/* Warning, some systems have data access alignment restrictions */
#if defined(sparc) || defined(mips)
...

   ARM CPUs like my iPaq's fail on unaligned reads as well. See the
following code for instance:

int main(void) {
   char foo[3] = { 0, 0, 0 }; *(short *)(foo+1) = 0x1234;
   printf("%.2x %.2x %.2x\n", foo[0], foo[1], foo[2]);
}

   On an x86 CPU it outputs the following:

00 34 12

   But on my ARM iPaq I get:

34 12 00

   So the above lines in /usr/include/SDL/SDL_net.h should be changed to
this:

/* Warning, some systems have data access alignment restrictions */
#if defined(sparc) || defined(mips) || defined(__arm__)
...

   Moreover, AFAIK unaligned reads are always decomposed into two
aligned reads on modern CPUs. I think it would be wise to drop them
completely and always set SDL_DATA_ALIGNED to 1.

-- System Information:
Debian Release: testing/unstable
Architecture: i386
Kernel: Linux c18 2.4.21-rc5 #2 Wed May 28 22:10:14 CEST 2003 i686
Locale: LANG=C, LC_CTYPE=fr_FR

Message #10 received at 212570-close@bugs.debian.org (full text, mbox, reply):

From: Mike Furr <mfurr@debian.org>

To: 212570-close@bugs.debian.org

Subject: Bug#212570: fixed in sdl-net1.2 1.2.5-3

Date: Tue, 07 Oct 2003 23:32:11 -0400

Source: sdl-net1.2
Source-Version: 1.2.5-3

We believe that the bug you reported is fixed in the latest version of
sdl-net1.2, which is due to be installed in the Debian FTP archive:

libsdl-net1.2-dev_1.2.5-3_i386.deb
  to pool/main/s/sdl-net1.2/libsdl-net1.2-dev_1.2.5-3_i386.deb
libsdl-net1.2_1.2.5-3_i386.deb
  to pool/main/s/sdl-net1.2/libsdl-net1.2_1.2.5-3_i386.deb
sdl-net1.2_1.2.5-3.diff.gz
  to pool/main/s/sdl-net1.2/sdl-net1.2_1.2.5-3.diff.gz
sdl-net1.2_1.2.5-3.dsc
  to pool/main/s/sdl-net1.2/sdl-net1.2_1.2.5-3.dsc



A summary of the changes between this version and the previous one is
attached.

Thank you for reporting the bug, which will now be closed.  If you
have further comments please address them to 212570@bugs.debian.org,
and the maintainer will reopen the bug report if appropriate.

Debian distribution maintenance software
pp.
Mike Furr <mfurr@debian.org> (supplier of updated sdl-net1.2 package)

(This message was generated automatically at their request; if you
believe that there is a problem with it please contact the archive
administrators by mailing ftpmaster@debian.org)


-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Format: 1.7
Date: Tue,  7 Oct 2003 23:15:39 -0400
Source: sdl-net1.2
Binary: libsdl-net1.2-dev libsdl-net1.2
Architecture: source i386
Version: 1.2.5-3
Distribution: unstable
Urgency: low
Maintainer: Mike Furr <mfurr@debian.org>
Changed-By: Mike Furr <mfurr@debian.org>
Description: 
 libsdl-net1.2 - network library for Simple DirectMedia Layer
 libsdl-net1.2-dev - Development files for SDL network library
Closes: 209732 212570
Changes: 
 sdl-net1.2 (1.2.5-3) unstable; urgency=low
 .
   * Improved the package description (Closes: 209732)
   * Added ARM to list in SDL_net.h of CPU's that are have data alignment
     issues.  (Closes: 212570) [also forwared this upstream]
Files: 
 8840f08a6006225748f163f469b24cf0 632 libs optional sdl-net1.2_1.2.5-3.dsc
 c0be3fb65f41670182c65ff774b1861e 19995 libs optional sdl-net1.2_1.2.5-3.diff.gz
 66d9925db614790c0b5bba44977748d2 15070 libdevel optional libsdl-net1.2-dev_1.2.5-3_i386.deb
 56809e52307e6df005d7161a18400de5 9832 libs optional libsdl-net1.2_1.2.5-3_i386.deb

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