2 files changed, 8 insertions, 2 deletions
diff --git a/MdeModulePkg/Universal/DebugSupportDxe/Ia32/AsmFuncs.asm b/MdeModulePkg/Universal/DebugSupportDxe/Ia32/AsmFuncs.asm
index 80ee1824d6..32cbc31654 100644
--- a/MdeModulePkg/Universal/DebugSupportDxe/Ia32/AsmFuncs.asm
+++ b/MdeModulePkg/Universal/DebugSupportDxe/Ia32/AsmFuncs.asm
@@ -1,7 +1,7 @@
 ;/** @file
 ;  Low leve IA32 specific debug support functions.
 ;
-;  Copyright (c) 2006, Intel Corporation. All rights reserved.<BR>
+;  Copyright (c) 2006 - 2011, 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
@@ -363,6 +363,9 @@ CommonIdtEntry::
                 ; They MUST be.  If they are not, a GP fault will occur.
                 FXSTOR_EDI
 
+;; UEFI calling convention for IA32 requires that Direction flag in EFLAGs is clear
+                cld
+
 ;; UINT32  ExceptionData;
                 mov     eax, ExceptData
                 push    eax
diff --git a/MdeModulePkg/Universal/DebugSupportDxe/X64/AsmFuncs.asm b/MdeModulePkg/Universal/DebugSupportDxe/X64/AsmFuncs.asm
index b9c32dd277..bce49ef762 100644
--- a/MdeModulePkg/Universal/DebugSupportDxe/X64/AsmFuncs.asm
+++ b/MdeModulePkg/Universal/DebugSupportDxe/X64/AsmFuncs.asm
@@ -1,7 +1,7 @@
 ;/** @file
 ;  Low level x64 routines used by the debug support driver.
 ;
-;  Copyright (c) 2007 - 2010, Intel Corporation. All rights reserved.<BR>
+;  Copyright (c) 2007 - 2011, 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
@@ -393,6 +393,9 @@ ExtraPushDone:
                 ; They MUST be.  If they are not, a GP fault will occur.
                 FXSTOR_RDI
 
+;; UEFI calling convention for x64 requires that Direction flag in EFLAGs is clear
+                cld
+
 ;; UINT64  ExceptionData;
                 mov     rax, ExceptData
                 push    rax