diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ExceptionHandlerAsm.S b/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ExceptionHandlerAsm.S
index 6e80d848fe..233dbcbcc5 100644
--- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ExceptionHandlerAsm.S
+++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ExceptionHandlerAsm.S
@@ -1,5 +1,5 @@
 #------------------------------------------------------------------------------ ;
-# Copyright (c) 2012 - 2013, Intel Corporation. All rights reserved.<BR>
+# Copyright (c) 2012 - 2014, 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
@@ -269,15 +269,15 @@ VectorNum:
 ASM_GLOBAL ASM_PFX(HookAfterStubHeaderEnd)
 ASM_PFX(HookAfterStubHeaderEnd):
     movq    %rsp, %rax
-    subq    $8, %rsp
-    andl    $0x0fffffff0, %esp
+    andl    $0x0fffffff0, %esp  # make sure 16-byte aligned for exception context
+    subq    $0x18, %rsp         # reserve room for filling exception data later
     pushq   %rcx
     movq    8(%rax), %rcx
     pushq   %rax
     movabsl ASM_PFX(mErrorCodeFlag), %eax
     bt      %ecx, %eax
     popq    %rax
-    jc      NoErrorData
+    jnc     NoErrorData
     pushq   (%rsp)            # push additional rcx to make stack alignment
 NoErrorData:
     xchgq   (%rsp), %rcx      # restore rcx, save Exception Number in stack
diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ExceptionHandlerAsm.asm b/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ExceptionHandlerAsm.asm
index f348efe4be..59bec5985a 100644
--- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ExceptionHandlerAsm.asm
+++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ExceptionHandlerAsm.asm
@@ -1,5 +1,5 @@
 ;------------------------------------------------------------------------------ ;
-; Copyright (c) 2012 - 2013, Intel Corporation. All rights reserved.<BR>
+; Copyright (c) 2012 - 2014, 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
@@ -53,12 +53,12 @@ HookAfterStubHeaderBegin:
     jmp     rax
 HookAfterStubHeaderEnd:
     mov     rax, rsp
-    sub     rsp, 8h
-    and     sp, 0fff0h
+    and     sp,  0fff0h        ; make sure 16-byte aligned for exception context
+    sub     rsp, 18h           ; reserve room for filling exception data later
     push    rcx
     mov     rcx, [rax + 8]
     bt      mErrorCodeFlag, ecx
-    jc      @F
+    jnc     @F
     push    [rsp]             ; push additional rcx to make stack alignment
 @@:
     xchg    rcx, [rsp]        ; restore rcx, save Exception Number in stack