From: Alan Modra <amodra@gmail.com>
To: Sebastian Huber <sebastian.huber@embedded-brains.de>
Cc: binutils@sourceware.org
Subject: Re: 32-bit PowerPC sdata linker problem
Date: Fri, 06 Jun 2014 12:15:00 -0000 [thread overview]
Message-ID: <20140606121531.GI5592@bubble.grove.modra.org> (raw)
In-Reply-To: <5391A6A4.6050708@embedded-brains.de>
On Fri, Jun 06, 2014 at 01:31:48PM +0200, Sebastian Huber wrote:
> On 2014-06-06 13:23, Sebastian Huber wrote:
> >Ok, so this "cmplwi cr0, rX, ppc_exc_lock_std@sdarel" is illegal, since
> >ppc_exc_lock_std@sdarel is signed and the immediate is unsigned 16-bit? The
> >assembler doesn't issue a warning about this.
> >
> >Exists there a way to rescue this cmplwi hack without relaxing the overflow
> >checks?
>
> Hm, sorry, it was surprisingly simple. This works:
>
> "cmplwi cr0, rX, ppc_exc_lock_std@sdarel@l"
>
> I was not aware that you can add several @ in a row.
That is the wrong thing to use here. sdarel@l translates to a VLE
reloc which applies to a split 16-bit field in VLE insns.
You want
cmpwi cr0, rX, ppc_exc_lock_std@sdarel
to properly compare a 16-bit signed number from sym@sdarel.
Note that the assembler does error if you write something like
cmplwi 3,-30000
or
cmpwi 3,40000
so what the linker is now doing is extending this behaviour to link
time.
--
Alan Modra
Australia Development Lab, IBM
next prev parent reply other threads:[~2014-06-06 12:15 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <53918356.3040102@embedded-brains.de>
2014-06-06 10:54 ` Alan Modra
2014-06-06 11:23 ` Sebastian Huber
2014-06-06 11:31 ` Sebastian Huber
2014-06-06 12:15 ` Alan Modra [this message]
2014-06-06 12:49 ` Sebastian Huber
[not found] ` <20140606130559.GK5592@bubble.grove.modra.org>
[not found] ` <5391C0E8.7010409@embedded-brains.de>
[not found] ` <20140606134915.GL5592@bubble.grove.modra.org>
[not found] ` <5391CCFB.5060206@embedded-brains.de>
2014-06-07 12:34 ` Alan Modra
2014-06-10 6:28 ` Sebastian Huber
2014-06-06 12:17 ` Alan Modra
2014-06-07 12:47 ` Alan Modra
2014-06-16 11:21 ` Will Newton
2014-06-16 13:07 ` Alan Modra
2014-06-16 14:10 ` Will Newton
2014-06-16 14:11 ` Will Newton
2014-06-18 0:29 ` Alan Modra
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