DOCUMENT:Q160610 08-AUG-2001 [winnt] TITLE :READ_REGISTER_ULONG Doesn't Preserve ULONG Semantics on Alpha PRODUCT :Microsoft Windows NT PROD/VER:winnt:4.0 OPER/SYS: KEYWORDS:kbhw kbHardware ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Windows NT Workstation version 4.0 - Microsoft Windows NT Server version 4.0 ------------------------------------------------------------------------------- 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 ====================================================================== Keywords : kbhw kbHardware Technology : kbWinNTsearch kbWinNTWsearch kbWinNTW400 kbWinNTW400search kbWinNT400search kbWinNTSsearch kbWinNTS400search kbWinNTS400 Version : winnt:4.0 ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. Copyright Microsoft Corporation 2001.