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Re: ldrb vs ldrh in gcc-3.4.4 (ARM)

From: Lennert Buytenhek <buytenh at wantstofly dot org>
To: Steven Scholz <steven dot scholz at imc-berlin dot de>
Cc: Richard Earnshaw <rearnsha at gcc dot gnu dot org>,Philip Blundell <pb at reciva dot com>,crossgcc <crossgcc at sources dot redhat dot com>
Date: Wed, 17 Aug 2005 15:57:11 +0200
Subject: Re: ldrb vs ldrh in gcc-3.4.4 (ARM)
References: <43033B8C.6050100@imc-berlin.de> <1124286169.18243.0.camel@mill.internal.reciva.com> <1124286398.14755.0.camel@pc960.cambridge.arm.com>

On Wed, Aug 17, 2005 at 02:46:38PM +0100, Richard Earnshaw wrote:

> > > I noticed that gcc-3.4.4 for ARM is using byte wise loading instructions 
> > > although word wise would be much better. Does anyone know why? gcc-3.3.3 is 
> > > doing it as I would expect.
> > 
> > Check your -march= setting.
> > 
> > p.
> 
> Or it might be a different 'default' CPU during configuration.

gcc 3.3.3 defaults to arm7tdmi, whereas gcc 3.3.[456] and gcc 3.4.?
default to arm6.

Steven, I suspect that if you use gcc 3.3.4, you'll also see the
byte loads.  (Not all ARM models support halfword loads and stores.)


--L

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References:
- ldrb vs ldrh in gcc-3.4.4 (ARM)
  - From: Steven Scholz
- Re: ldrb vs ldrh in gcc-3.4.4 (ARM)
  - From: Philip Blundell
- Re: ldrb vs ldrh in gcc-3.4.4 (ARM)
  - From: Richard Earnshaw

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