diff options
| author |   Angelos Mouzakitis <a.mouzakitis@virtualopensystems.com> | 2023-10-10 14:33:42 +0000 |
|---|---|---|
| committer | Angelos Mouzakitis <a.mouzakitis@virtualopensystems.com> | 2023-10-10 14:33:42 +0000 |
| commit | af1a266670d040d2f4083ff309d732d648afba2a (patch) | |
| tree | 2fc46203448ddcc6f81546d379abfaeb323575e9 /roms/edk2/MdePkg/Library/BaseLib/Ia32/WriteDr4.nasm | |
| parent | e02cda008591317b1625707ff8e115a4841aa889 (diff) | |
Change-Id: Iaf8d18082d3991dec7c0ebbea540f092188eb4ec
Diffstat (limited to 'roms/edk2/MdePkg/Library/BaseLib/Ia32/WriteDr4.nasm')
| -rw-r--r-- | roms/edk2/MdePkg/Library/BaseLib/Ia32/WriteDr4.nasm | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/roms/edk2/MdePkg/Library/BaseLib/Ia32/WriteDr4.nasm b/roms/edk2/MdePkg/Library/BaseLib/Ia32/WriteDr4.nasm new file mode 100644 index 000000000..0d23fca11 --- /dev/null +++ b/roms/edk2/MdePkg/Library/BaseLib/Ia32/WriteDr4.nasm @@ -0,0 +1,39 @@ +;------------------------------------------------------------------------------
+;
+; Copyright (c) 2006, Intel Corporation. All rights reserved.<BR>
+; SPDX-License-Identifier: BSD-2-Clause-Patent
+;
+; Module Name:
+;
+; WriteDr4.Asm
+;
+; Abstract:
+;
+; AsmWriteDr4 function
+;
+; Notes:
+;
+;------------------------------------------------------------------------------
+
+ SECTION .text
+
+;------------------------------------------------------------------------------
+; UINTN
+; EFIAPI
+; AsmWriteDr4 (
+; IN UINTN Value
+; );
+;------------------------------------------------------------------------------
+global ASM_PFX(AsmWriteDr4)
+ASM_PFX(AsmWriteDr4):
+ mov eax, [esp + 4]
+ ;
+ ; DR4 is alias to DR6 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, 0xe0
+ ret
+
|