diff options
Diffstat (limited to 'Core/MdePkg/Library/BaseLib/Ia32/WriteDr5.nasm')
-rw-r--r-- | Core/MdePkg/Library/BaseLib/Ia32/WriteDr5.nasm | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/Core/MdePkg/Library/BaseLib/Ia32/WriteDr5.nasm b/Core/MdePkg/Library/BaseLib/Ia32/WriteDr5.nasm new file mode 100644 index 0000000000..8d1f9e6911 --- /dev/null +++ b/Core/MdePkg/Library/BaseLib/Ia32/WriteDr5.nasm @@ -0,0 +1,45 @@ +;------------------------------------------------------------------------------
+;
+; Copyright (c) 2006, Intel Corporation. All rights reserved.<BR>
+; This program and the accompanying materials
+; are licensed and made available under the terms and conditions of the BSD License
+; which accompanies this distribution. The full text of the license may be found at
+; http://opensource.org/licenses/bsd-license.php.
+;
+; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+;
+; Module Name:
+;
+; WriteDr5.Asm
+;
+; Abstract:
+;
+; AsmWriteDr5 function
+;
+; Notes:
+;
+;------------------------------------------------------------------------------
+
+ SECTION .text
+
+;------------------------------------------------------------------------------
+; UINTN
+; EFIAPI
+; AsmWriteDr5 (
+; IN UINTN Value
+; );
+;------------------------------------------------------------------------------
+global ASM_PFX(AsmWriteDr5)
+ASM_PFX(AsmWriteDr5):
+ 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 0xf, 0x23, 0xe8
+ ret
+
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