RE: [ECOS] Adding xscale support to my eCos config

[C B <csb_80@hotmail.com>]

Yes, I believe it should just be a compiler issue.

I'll have to look into the 'march' flag but I had tried to compile my application with -mcpu=xscale and I got an error message saying that libtarget.a uses FPA instructions where as my app uses VFP instructions.  So, I assumed I need to similarly modify how I build eCos but it's not clear to me at the moment where to make that change (at least within the configtool).


> Date: Wed, 14 Nov 2007 14:30:44 +0100
> From: andrew@lunn.ch
> To: csb_80@hotmail.com
> CC: ecos-discuss@ecos.sourceware.org
> Subject: Re: [ECOS] Adding xscale support to my eCos config
>
> On Wed, Nov 14, 2007 at 08:19:46AM -0500, C B wrote:
>>
>>
>
>> Coming from a long background developing Applications in Java to the
>> embedded world is quite a switch so please bear with me. I've got
>> an eCos configuration working based on the latest from CVS for an
>> ARM9 based target from Atmel. I've written simple applications in
>> C, linked against the eCos libs and successfully executed them on my
>> target. So, my question: My target supports an extended DSP
>> instruction set (xscale). I see an xscale package in the eCos I've
>> checked out but it is not clear to me how I get from my current eCos
>> configuration to one in which I can make calls from my C application
>> to make use of the xscale instruction set. I would appreciate any
>> hints. Thanks!
>
> Isn't this just a compiler issue? So long as the compile knows you are
> using an xscale with these extra instructions, it should use them.
>
> Look what flags are passed to the compiler, in particular march.
>
> If you want to explicitly call these xscale instructions, you will
> need to do inline/out of line assembly language programming, or find a
> library from somewhere which has wrapped them up in something easier
> to use.
>
> Andrew

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