GNATS-1110: in_cksum_hdr error in PC386 BSP

Till Straumann strauman at slac.stanford.edu
Wed Jun 28 16:44:59 UTC 2006


Weird - I very recently (1week ago) tested
networking in qemu (i386 target, i386-linux host)
and I didn't notice anything unusual.
I'm still using gcc-4.0.2 (rtems CVS head).

-- Till

Ralf Corsepius wrote:

>On Wed, 2006-06-28 at 09:54 -0500, Eric Norum wrote:
>  
>
>>On Jun 28, 2006, at 9:39 AM, Ralf Corsepius wrote:
>>
>>    
>>
>>>On Wed, 2006-06-28 at 08:47 -0500, Eric Norum wrote:
>>>
>>>
>>>      
>>>
>>>>The checksum routines are very heavily used so it's really
>>>>important  
>>>>that they be as fast as possible.  Do you have an estimate of the
>>>> 
>>>>relative times of the old and new versions of this code?
>>>>        
>>>>
>>>heavily used and broken don't align smoothly.
>>>      
>>>
>>Yes, I think that they might in this case.
>>1) This problem may have just shown up as a result of the change from
>>gcc-3.x to gcc-4.x.
>>2) Joel has reported for some time that qemu has been broken.
>>    
>>
>Somebody might want to test on real hardware.
>
>  
>
>>>Either these routines have been heavily used, then they must have
>>>been
>>>working, or not - Then I don't understand why nobody has tripped
>>>over
>>>this issue in the years this code is in place.
>>>      
>>>
>>Because in previous years they were using a different tool chain.
>>    
>>
>It's always a comfortable excuse to accuse the toolchain :-)
>
>Did you check the asm being generated?
>
>  
>
>>>IMO, the PR is way to vague to give any trust in it.
>>>      
>>>
>>Others have reported problems with networking on the pc386.
>>    
>>
>This doesn't mean much, esp. because most networking on little endian
>targets always is a magnitude difficult than on big endian ones.
>
>  
>
>>  This is the first time I've seen a patch though.
>>    
>>
>I presume, explicitly testing this checksum code on real hardware with
>somebody being familiar to i386s isn't much of a problem.
>
>Ralf
>
>
>
>  
>




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