Re: Misaligned accesses with MS ARM compiler

From: Alan Gillespie (agillesp_at_qualcomm.com)
Date: 04/28/04 

Date: Wed, 28 Apr 2004 17:36:51 +0100

At the risk of appearing ignorant - you are talking about the MS ARM compiler as included with eVC4, aren't you? As in
clarm.exe (I have version 12.20.9615)?

I just looked at the compiler documentation and couldn't find any mention of UNALIGNED of __unaligned anywhere.

--Alan Gillespie.

"Michael J. Salamone [eMVP]" <mikesa#at#entrek#dot#com> wrote in message news:ug8WSkTLEHA.1264@TK2MSFTNGP12.phx.gbl...
> Use UNALIGNED in your declararation - which resolves to __unaligned keyword.
>
> --
>
> Michael Salamone [eMVP]
> Entrek Software, Inc.
> www.entrek.com
>
>
>
> "Alan Gillespie" <agillesp@qualcomm.com> wrote in message
> news:e1TOPcTLEHA.1272@tk2msftngp13.phx.gbl...
> >
> > Does anyone know of a way to tell the ARM compiler that a WORD or DWORD
> pointer addresses an object that is not (or
> > might not be) aligned on a 16 or 32 bit boundary?
> >
> > Effectively what I want to do is this:
> >
> > BYTE *pBuffer = malloc(something);
> > WORD *pWord = (WORD *) &pBuffer[arbitrary_offset];
> > DWORD *pDWord = (DWORD *) &pBuffer[another_arbitrary_offset];
> >
> > *pWord = word_value; /* May be misaligned */
> > *pDWord = dword_value; /* May be misaligned */
> >
> > I have tried various versions of #pragma pack() without success. I could,
> of course, use WORD and DWORD temporaries and
> > memcpy() into the array but that is messy. There are other, equally messy,
> workarounds involving byte manipulation.
> >
> > The problem arises because I am porting a large amount of code that was
> written for the ARM ADS compiler, which has such
> > a facility.
> >
> > Thanks,
> > --Alan Gillespie.
> >
> >
>
>