diff --git a/MdePkg/Library/BaseLib/BaseLib.inf b/MdePkg/Library/BaseLib/BaseLib.inf index f57b6cd88f..8af7bdb349 100644 --- a/MdePkg/Library/BaseLib/BaseLib.inf +++ b/MdePkg/Library/BaseLib/BaseLib.inf @@ -273,6 +273,7 @@ Ia32/ReadDr6.asm | INTEL Ia32/ReadDr5.nasm| INTEL Ia32/ReadDr5.asm | INTEL + Ia32/ReadDr4.nasm| INTEL Ia32/ReadDr4.asm | INTEL Ia32/ReadDr3.asm | INTEL Ia32/ReadDr2.asm | INTEL diff --git a/MdePkg/Library/BaseLib/Ia32/ReadDr4.nasm b/MdePkg/Library/BaseLib/Ia32/ReadDr4.nasm new file mode 100644 index 0000000000..478c50e47b --- /dev/null +++ b/MdePkg/Library/BaseLib/Ia32/ReadDr4.nasm @@ -0,0 +1,44 @@ +;------------------------------------------------------------------------------ +; +; Copyright (c) 2006, Intel Corporation. All rights reserved.
+; 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: +; +; ReadDr4.Asm +; +; Abstract: +; +; AsmReadDr4 function +; +; Notes: +; +;------------------------------------------------------------------------------ + + SECTION .text + +;------------------------------------------------------------------------------ +; UINTN +; EFIAPI +; AsmReadDr4 ( +; VOID +; ); +;------------------------------------------------------------------------------ +global ASM_PFX(AsmReadDr4) +ASM_PFX(AsmReadDr4): + ; + ; DR4 is alias to DR6 only if DE (in CR4) is cleared. Otherwise, reading + ; 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, 0x21, 0xe0 + ret +