From mboxrd@z Thu Jan  1 00:00:00 1970
From: Avi Kivity <avi@redhat.com>
Subject: Re: [PATCH 1/2] KVM: x86 emulator: put register operand write back
 to a function
Date: Mon, 16 Aug 2010 11:55:55 +0300
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References: <4C63F947.7020808@cn.fujitsu.com> <4C67CFC5.6060900@redhat.com> <4C689B56.4000405@cn.fujitsu.com>
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To: Wei Yongjun <yjwei@cn.fujitsu.com>
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 On 08/16/2010 04:58 AM, Wei Yongjun wrote:
>     
>> It's cleaner to take val and bytes from struct operand, and do the
>> assignment from the callers, no?
>>   
> take val and bytes from struct operand may have other issue, when we
> writeback
> the source register, we need do the assignment from the caller, and then
> change
> the val back before write src val to dst val. Such as xadd:
> c->src.val = c->dst.val;
> write_register_operand(&c->src);
> c->src.val = c->src.orig_val;
> goto add;

Or avoid the 'goto add'. XADD is not ADD.

write_register_operand(struct operand *) is easy to understand. With the
two additional arguments it becomes confusing since it uses some parts
of the operand but ignores others.

-- 
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.