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Date: Mon, 09 Jun 2008 22:21:01 +0200
From: Fabrice Bellard <fabrice@bellard.org>
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Subject: Re: [Qemu-devel] [4705] Fix div[u]2.
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To: qemu-devel@nongnu.org

malc wrote:
> On Mon, 9 Jun 2008, Fabrice Bellard wrote:
> 
>> malc wrote:
>>> Revision: 4705
>>>           http://svn.sv.gnu.org/viewvc/?view=rev&root=qemu&revision=4705
>>> Author:   malc
>>> Date:     2008-06-09 06:06:25 +0000 (Mon, 09 Jun 2008)
>>>
>>> Log Message:
>>> -----------
>>> Fix div[u]2.
>>>
>>> Previous code assummed 32 by 32 bit divmod operation, and survived
>>> x86_64 test only by sheer luck. MIPS wasn't so forgiving.
>>
>> Are you sure it is needed ? div[u]2 support in currently optional in
>> TCG. On some hosts such as PowerPC, implementing div[u] directly is
>> simpler. rem[u] can be implemented generically then.
> 
> When i added TCG_TARGET_HAS_div_i32 plus all that is necessary to handle
> div[u]/rem[u]_i32 tcg started to abort at tcg.c:1180 (at least for
> arm-softmmu)

So this is the bug to solve. Adding divu2 is not necessary, at least
until we decided it is necessary for all TCG targets.

Fabrice.