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Date: Fri, 09 Apr 2010 08:42:07 +0200
From: Stefan Weil <weil@mail.berlios.de>
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Subject: [Qemu-devel] Re: [PATCH] tcp/mips: Change TCG_AREG0 (fp -> s0)
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To: Aurelien Jarno <aurelien@aurel32.net>
Cc: QEMU Developers <qemu-devel@nongnu.org>

Aurelien Jarno schrieb:
> On Thu, Apr 08, 2010 at 03:38:52PM +0200, Stefan Weil wrote:
>   
>> Register fp is a bad choice for compilations without
>> optimisation, because the compiler makes heavy use
>> of this register (so the resulting code crashes).
>>     
>
> I don't fully understand why the compiler makes use of this register in 
> code where env is declared as register fp.
>   

fp = frame pointer is special. See Paul's answer.

>   
>> Register s0 was used for TCG_AREG1 in earlier releases,
>> but was no longer used and is now free for TCG_AREG0.
>>
>> The resulting code works for compilations without
>> optimisation (tested with qemu mips in qemu mips
>> on x86 host).
>>     
>
> The patch is not complete, at least some changes are missing to 
> tcg_target_callee_save_regs.
>   

Thanks. I'll send an updated patch.

Regards, Stefan