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Date:	Thu, 28 May 2009 08:43:18 -0700
From:	David Daney <ddaney@caviumnetworks.com>
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To:	Ralf Baechle <ralf@linux-mips.org>
CC:	wuzhangjin@gmail.com, Florian Fainelli <florian@openwrt.org>,
	Richard Sandiford <rdsandiford@googlemail.com>,
	"Maciej W. Rozycki" <macro@linux-mips.org>,
	linux-mips@linux-mips.org
Subject: Re: [PATCH] MIPS: Handle removal of 'h' constraint in GCC 4.4
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Wu Zhangjin wrote:
> Hi, 
> 
> On Thu, 2009-05-28 at 13:31 +0200, Florian Fainelli wrote:
>> Le Saturday 27 December 2008 16:19:40 Richard Sandiford, vous avez écrit :
>>> "Maciej W. Rozycki" <macro@linux-mips.org> writes:
>>>> On Wed, 17 Dec 2008, David Daney wrote:
>>>>> This is an incomplete proof of concept that I applied to be able to
>>>>> build a 64 bit kernel with GCC-4.4.  It doesn't handle the 32 bit case
>>>>> or the R4000_WAR case.
>>>>  The R4000_WAR case can use the same C code -- GCC will adjust code
>>>> generated as necessary according to the -mfix-r4000 flag.  For the 32-bit
>>>> case I think the conclusion was the only way to get it working is to use
>>>> MFHI explicitly in the asm.
>>> No, the same sort of cast, multiply and shift should work for 32-bit
>>> code too.  I.e.:
>>>
>>> 		usecs = ((uint64_t)usecs * lpj) >> 32;
>>>
>>> It should work for both -mfix-r4000 and -mno-fix-r4000.
>> Any updates on this ?
> 
> I have updated it to this PATCH, could you help to review it?
> 
> 
> 

FWIW, Ralf also has a patch, that I have tested, that takes a slightly 
different approach.

In any event, it would be nice if one of the patches were merged to 
2.6.30 before it is released.  GCC-4.4 has been available for quite a 
while now.  Not being able to build the kernel with it will become a 
larger issue as time goes by.

David Daney