[Winpcap-users] Winpcap in Intanium machine

Fish fish at infidels.org
Fri Oct 9 19:17:27 PDT 2009


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Gianluca Varenni wrote:

[...]
> The exception code 80000002 means
> a.. 0x80000002: STATUS_DATATYPE_MISALIGNMENT indicates that an
> unaligned data reference was encountered.
> 
> and it's probably because the Itanium doesn't allow unaligned access
> to memory (i.e. if you try to access a 64bit integer, its address
> should be aligned to 64bit). x86 and x64 do not have such requirement,
> and the WinPcap driver relies on that.

Forgive me for asking, but WHY does WinPcap *rely* on unaligned access?!

Just because a particular CPU architecture doesn't *require* operand alignment for certain instructions doesn't mean that one doesn't need to bother trying to ensure that ALL of its data fields are properly aligned!

I mean, it may work on certain architectures (such as x86 and x64) but you WILL pay a significant performance penalty.

And as the OP is discovering, on certain architectures (such as the Itanium) such programs will not even run.
 
I would personally treat that as a BUG that needs to be fixed.

- -- 
"Fish" (David B. Trout) - fish at softdevlabs.com
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