Why do Windows functions begin with a pointless MOV EDI, EDI instruction? (2011)

Re:Why do Windows functions begin with a pointless MOV EDI, ... by djpowell on Thursday February 11, 2016 @06:26AM (#11079504)

I love this one, about DirectX not trusting drivers responses to capabilities requests: https://blogs.msdn.microsoft.com/oldnewthing/20040211-00/?p=...

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Re:Why do Windows functions begin with a pointless MOV EDI, ... by Pxtl on Thursday February 11, 2016 @07:37AM (#11079740)

I thought guids weren't based on MAC addresses anymore.

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Re:Why do Windows functions begin with a pointless MOV EDI, ... by CJefferson on Thursday February 11, 2016 @07:45AM (#11079768)

They aren't, but they were when this original "bug" in drivers was fixed.

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Re:Why do Windows functions begin with a pointless MOV EDI, ... by billpg on Thursday February 11, 2016 @08:39AM (#11079999)

So they wasted a perfectly good network card for nothing.

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Re:Why do Windows functions begin with a pointless MOV EDI, ... by periodontal on Thursday February 11, 2016 @01:12PM (#11081801)

They destroyed it ostensibly so that they had a stronger guarantee that that GUID would never be generated again. That said, I suspect they understood it wasn't strictly necessary and were looking for an excuse to have some fun.

Note that even in the MAC-based generation algorithm, it is difficult (but not impossible) to accidentally generate the same one again even on the same hardware since there is a high resolution time component as well.

Random UUIDs have a different encoded version number so it's actually impossible for a modern one to collide with the one they generated.

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