FIX: Page Table Initialization Missing in x86 OAL

• Microsoft Windows CE Embedded Toolkit for Visual C++ 5.0

SYMPTOMS

An x86-based implementation of the Windows CE operating system does not boot when a custom physical memory layout is used.

CAUSE

The Windows CE x86 OAL code supplied in the Windows CE Embedded Toolkit for Visual C++ 5.0 lacks an OEM customizable routine to preset entries into the page table. This prevents the OEM from building a proper initial virtual memory address space during system initialization.

RESOLUTION

To correct this problem, the Windows CE kernel component NK.LIB has been updated to call a new OAL function, OEMInitPageTable(). A new OAL sample file has been added (Oeminit.asm) to implement this new OAL function. By modifying the OEMInitPageTable() function an OEM can properly build the initial page table to match the physical memory layout of the platform.

STATUS

Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. This bug has been corrected in the Windows CE 2.1 Enhancement Pack for the Embedded Toolkit, and is also available as a patch for Windows CE 2.0 from Microsoft Developer support.

MORE INFORMATION

The Windows CE x86 kernel contains an initial page table that maps memory resources for a x86 development platform. This page table may not be appropriate for all other x86 platform implementations.

Flash memory, additional DRAM, and ROM address space may not be a part of the built-in page table and will cause the system to halt when the switch from physical addressing to virtual addressing takes place.

Additional query words: wceoem

Keywords : kbETK kbVC500
Version : WINDOWS:
Platform : WINDOWS
Issue type : kbbug