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Q160610: READ_REGISTER_ULONG Doesn’t Preserve ULONG Semantics on Alpha

Article: Q160610
Product(s): Microsoft Windows NT
Version(s): winnt:4.0
Operating System(s): 
Keyword(s): kbhw kbHardware
Last Modified: 08-AUG-2001

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The information in this article applies to:

- Microsoft Windows NT Workstation version 4.0 
- Microsoft Windows NT Server version 4.0 
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SYMPTOMS
========

The READ_REGISTER_ULONG routine in the HAL for Alpha platform computers does not
preserve the ULONG semantics, which may cause the computer to stop responding or
bugcheck.

CAUSE
=====

Currently, the READ_REGISTER_ULONG routing explicitly zeros out the upper four
bytes of the return value. This will destroy ULONG semantics, where bit 31 is
sign extended through to bit 63. This will potentially cause drivers that poke
memory mapped I/O for expected signatures to fail when comparing the return
value of READ_REGISTER_ULONG to a static constant when bit 31 of the constant is
set.

STATUS
======

Microsoft has confirmed this to be a problem in Microsoft Windows NT version
4.0.
This problem was corrected in the latest Microsoft Windows NT 4.0 U.S. Service
Pack. For information on obtaining the service pack, query on the following word
in the Microsoft Knowledge Base (without the spaces):

  S E R V P A C K


Additional query words: prodnt alpha

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Keywords          : kbhw kbHardware 
Technology        : kbWinNTsearch kbWinNTWsearch kbWinNTW400 kbWinNTW400search kbWinNT400search kbWinNTSsearch kbWinNTS400search kbWinNTS400
Version           : winnt:4.0

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