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From: "Philippe De Muyter" <phdm@macqel.be>
To: jvickers@dial.pipex.com (John Vickers)
Cc: schwab@issan.informatik.uni-dortmund.de, smurf@noris.de, egcs@cygnus.com
Subject: Re: Incrementing volatiles?
Date: Mon, 13 Jul 1998 02:36:00 -0000	[thread overview]
Message-ID: <199807130936.LAA03530@mail.macqel.be> (raw)
In-Reply-To: <35A6B622.6F3EFF10@dial.pipex.com>

Sorry to be slightly off-topic, but this discussion reminds me a problem
I encountered some months ago when writing a driver for a VME board in
an AIX powerpc environment.  Although I had declared all the registers
of the chips on the board as volatile, and compiled my driver with gcc,
I saw with a logic analyser on the VME bus that the accesses to the
register on the board were not done in the order I had written them.
To solve that problem, I had to manually add asm("eieio") after each
access to a volatile register.  Should gcc not do that for me ?

eieio stands for "Enforce In-Order Execution of I/O".  Without it a powerpc
processor assumes that it may reorder the load and stores to memory-mapped
I/O registers.

  reply	other threads:[~1998-07-13  2:36 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
1998-07-08 14:20 Matthias Urlichs
1998-07-10  6:04 ` Andreas Schwab
1998-07-10 21:04   ` John Vickers
1998-07-13  2:36     ` Philippe De Muyter [this message]
1998-07-13  2:40       ` Andreas Schwab
1998-07-13  4:36         ` Philippe De Muyter
1998-07-13  8:48       ` Joe Buck
1998-07-15  6:45         ` Andi Kleen
1998-07-13 12:40       ` Franz Sirl
1998-07-11  6:03   ` Horst von Brand
1998-07-13  1:48     ` Andreas Schwab
1998-07-14 18:59       ` Bill Currie
1998-07-15  1:49         ` Jeffrey A Law
1998-07-15 17:22           ` Bill Currie
1998-07-15 17:22             ` Jeffrey A Law
1998-07-15 17:56               ` Bill Currie
1998-07-15 17:22                 ` Jeffrey A Law
1998-07-15 17:34                 ` Matthias Urlichs
1998-07-15 21:58                   ` Bill Currie
1998-07-16 11:28                   ` Carlo Wood
1998-07-17  4:06                 ` Andreas Schwab
1998-07-15  3:14         ` Andreas Schwab
1998-07-15 17:22           ` Carlo Wood
1998-07-17  4:10             ` Andreas Schwab
1998-07-15  3:14         ` Joern Rennecke
     [not found] <egcs.199807111302.JAA10664@pincoya.inf.utfsm.cl>
1998-07-13  0:06 ` Todd P. Whitesel
1998-07-17  8:59 Mike Stump

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