1 files changed, 49 insertions, 0 deletions
diff --git a/Core/MdePkg/Library/BaseLib/Ia32/WriteMsr64.c b/Core/MdePkg/Library/BaseLib/Ia32/WriteMsr64.c
new file mode 100644
index 0000000000..2f22f49fbd
--- /dev/null
+++ b/Core/MdePkg/Library/BaseLib/Ia32/WriteMsr64.c
@@ -0,0 +1,49 @@
+/** @file
+  AsmWriteMsr64 function
+
+  Copyright (c) 2006 - 2008, 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.
+
+**/
+
+
+
+
+/**
+  Writes a 64-bit value to a Machine Specific Register(MSR), and returns the
+  value.
+
+  Writes the 64-bit value specified by Value to the MSR specified by Index. The
+  64-bit value written to the MSR is returned. No parameter checking is
+  performed on Index or Value, and some of these may cause CPU exceptions. The
+  caller must either guarantee that Index and Value are valid, or the caller
+  must establish proper exception handlers. This function is only available on
+  IA-32 and x64.
+
+  @param  Index The 32-bit MSR index to write.
+  @param  Value The 64-bit value to write to the MSR.
+
+  @return Value
+
+**/
+UINT64
+EFIAPI
+AsmWriteMsr64 (
+  IN UINT32  Index,
+  IN UINT64  Value
+  )
+{
+  _asm {
+    mov     edx, dword ptr [Value + 4]
+    mov     eax, dword ptr [Value + 0]
+    mov     ecx, Index
+    wrmsr
+  }
+}
+