861
Subj : Re: std::msync
To   : comp.programming.threads
From : Alexander Terekhov
Date : Wed Apr 06 2005 09:59 pm

< Forward Inline >

-------- Original Message --------
Message-ID: <425423FE.30C8D4DF@web.de>
Subject: Re: shared_ptr on ppc?
References: ... <42541BB5.AE56E560@web.de>

Alexander Terekhov wrote:
[...]
> Got it now. Thanks.

  asm long atomic_decrement_weak( register long * pw ) {

      <load-UNreserved>
      <add -1>
      <branch if zero to acquire>

      {lw}sync

    loop:

      <load-reserved>
      <add -1>
      <branch if zero to acquire>
      <store-conditional>
      <branch if failed to loop else to done>

    acquire:

      isync

    done:

      <...>
  }

 asm long atomic_decrement_strong( register long * pw ) { 

    // Peter's state machine

    loop0:

      <load-reserved>
      <add -1>
      <branch if zero to loop0_acquire>

      {lw}sync

    loop1:

      <store-conditional>
      <branch if !failed to done>

    loop2:

      <load-reserved>
      <add -1>
      <branch if !zero to loop1>
      <store-conditional>
      <branch if failed to loop2 else to acquire>

    loop0_acquire:

      <store-conditional>
      <branch if failed to loop0>

    acquire:

      isync

    done:

      <...>
  }

All right now?

regards,
alexander.

< Forward Quoted > [Message-ID: f4bc7d7d1041b71c5450aa06b68936ee@twcny.rr.com]

Howard Hinnant wrote:
> 
> On Apr 6, 2005, at 12:36 PM, Alexander Terekhov wrote:
> 
> >
> > Alexander Terekhov wrote:
> >
> > [... asm long atomic_decrement_[weak|strong] ...]
> >
> > I suppose that CodeWarrior is smart enough to recognize the presence of
> > msync instructions and will behave accordingly with respect to compiler
> > caching/reordering across these routines. If not, things can go wild,
> > beware.
> 
> Your assumption is correct.  CodeWarrior won't reorder across these
> instructions.
> 
> -Howard
> 
> _______________________________________________
> Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost

.

0