Is it possible that gcc reorders a series of read/write operations?

David Daney ddaney@avtrex.com
Fri Sep 5 04:01:00 GMT 2008


Pan ruochen wrote:
>> The instructions are executed in order.  The problem is that the write
>> operations in IO space are sometimes reordered.  On this board, flushing the
>> write-back buffer after IO writes is required.
>>
>> David Daney
>>
> 
> Here, the write-back buffer means the instruction cache of MIPS?
> 
No.

It is separate from the caches and was intended to coalesce adjacent 
writes into a single wider write.  It had the problem that it could end 
up reordering the writes under some circumstances even through uncached 
portions of the address space.

David Daney



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