diff options
| author | bxing <bxing@6f19259b-4bc3-4df7-8a09-765794883524> | 2007-01-10 06:57:04 +0000 |
|---|---|---|
| committer | bxing <bxing@6f19259b-4bc3-4df7-8a09-765794883524> | 2007-01-10 06:57:04 +0000 |
| commit | a9a812a0ed4ab3d83941fdc6da281aebdb9bb296 (patch) | |
| tree | 869ad144d2c1dcd96d859a9ac4c40617dfc96588 /MdePkg/Library/BaseLib/Ia32/WriteDr5.asm | |
| parent | 741fb364170375f89aa9c29488cc402db07a3776 (diff) | |
| download | edk2-platforms-a9a812a0ed4ab3d83941fdc6da281aebdb9bb296.tar.xz | |
1. Added comments to ASM files
2. Fixed a bug in 64-bit AsmDisablePaging64(), which may cause a #GP exception.
git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@2206 6f19259b-4bc3-4df7-8a09-765794883524
Diffstat (limited to 'MdePkg/Library/BaseLib/Ia32/WriteDr5.asm')
| -rw-r--r-- | MdePkg/Library/BaseLib/Ia32/WriteDr5.asm | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/MdePkg/Library/BaseLib/Ia32/WriteDr5.asm b/MdePkg/Library/BaseLib/Ia32/WriteDr5.asm index c6def6820c..e10434ef3d 100644 --- a/MdePkg/Library/BaseLib/Ia32/WriteDr5.asm +++ b/MdePkg/Library/BaseLib/Ia32/WriteDr5.asm @@ -34,6 +34,13 @@ ;------------------------------------------------------------------------------
AsmWriteDr5 PROC
mov eax, [esp + 4]
+ ;
+ ; DR5 is alias to DR7 only if DE (in CR4) is cleared. Otherwise, writing to
+ ; this register will cause a #UD exception.
+ ;
+ ; MS assembler doesn't support this instruction since no one would use it
+ ; under normal circustances. Here opcode is used.
+ ;
DB 0fh, 23h, 0e8h
ret
AsmWriteDr5 ENDP
|