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From: Michael Ellerman <michael@ellerman.id.au>
To: David Laight <David.Laight@ACULAB.COM>
Cc: linuxppc-dev@lists.ozlabs.org
Subject: RE: pread() and pwrite() system calls
Date: Tue, 29 May 2012 18:54:23 +1000	[thread overview]
Message-ID: <1338281663.15519.2.camel@concordia> (raw)
In-Reply-To: <AE90C24D6B3A694183C094C60CF0A2F6026B6F29@saturn3.aculab.com>

On Tue, 2012-05-29 at 09:28 +0100, David Laight wrote:
> > > A special pread/pwrite asm stub that just copies
> > > r7 to r0 could be used.
> > > 
> > > Would it be enough to do:
> > > syscall_pread_pwrite:
> > > 	mov 0,7
> > > 	sc
> > > 	blr
> > > and handle the -ve -> errno in C?
> > 
> > Huh? Won't fly, r0 is used for the system call number!
> 
> I was copying that from r7!

Using the non-existant 'mov' instruction!

or 0,7,7

is much clearer :)

cheers

  reply	other threads:[~2012-05-29  8:54 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-05-25 13:29 pread() and pwrite() system calls David Laight
2012-05-25 16:45 ` Gabriel Paubert
2012-05-29  8:28   ` David Laight
2012-05-29  8:54     ` Michael Ellerman [this message]
2012-05-30 10:56   ` David Laight

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