libstdc++/3584

libstdc++/3584

[rearnsha]

The following reply was made to PR libstdc++/3584; it has been noted by GNATS.

From: rearnsha@gcc.gnu.org
To: gcc-gnats@gcc.gnu.org
Cc:  
Subject: libstdc++/3584
Date: 3 Oct 2002 15:58:29 -0000

 CVSROOT:	/cvs/gcc
 Module name:	gcc
 Changes by:	rearnsha@gcc.gnu.org	2002-10-03 08:58:29
 
 Modified files:
 	libstdc++-v3   : ChangeLog 
 	libstdc++-v3/config/cpu/arm: atomicity.h 
 
 Log message:
 	PR libstdc++/3584
 	* config/cpu/arm/atomicity.h (__exchange_and_add): Don't try to use
 	ASM sequences that don't give us atomic addition operations.  Instead
 	just add a comment explaining why it doesn't work.
 	(__atomic_add): Just use __exchange_and_add.
 	(__test_and_set, __always_swap): Delete.
 
 Patches:
 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libstdc++-v3/ChangeLog.diff?cvsroot=gcc&r1=1.1374&r2=1.1375
 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libstdc++-v3/config/cpu/arm/atomicity.h.diff?cvsroot=gcc&r1=1.3&r2=1.4
 

Re: libstdc++/3584

[Robin Farine]

The following reply was made to PR libstdc++/3584; it has been noted by GNATS.

From: Robin Farine <acnrf@dial.eunet.ch>
To: gcc-gnats@gcc.gnu.org, gcc-prs@gcc.gnu.org, robin.farine@terminus.org,
        acnrf@dial.eunet.ch, gcc-bugs@gcc.gnu.org, nobody@gcc.gnu.org
Cc:  
Subject: Re: libstdc++/3584
Date: 07 Jul 2001 15:13:04 +0200

 This message improves the syntax and semantics of the description I have
 provided when I registered the bug report.
 
 Description: Routines such as atomic_add() that read a memory location, apply
              operations to the value read, use the swp instruction to update the
              memory location and swp again if the value read the 2nd time
              doesn't equal the value initially read, introduce a race
              condition. The attachment illustrates such a case.
 
 Robin
 
 http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view&pr=3584&database=gcc