diff --git a/EdkCompatibilityPkg/Foundation/Library/Thunk16/Ia32/Thunk16.S b/EdkCompatibilityPkg/Foundation/Library/Thunk16/Ia32/Thunk16.S
new file mode 100644
index 0000000000..facbe46c93
--- /dev/null
+++ b/EdkCompatibilityPkg/Foundation/Library/Thunk16/Ia32/Thunk16.S
@@ -0,0 +1,183 @@
+#*****************************************************************************
+#*
+#*   Copyright (c) 2006 - 2007, 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:
+#*
+#*    Thunk.asm
+#*  
+#*   Abstract:
+#*  
+#*    Real mode thunk
+#*  
+#*****************************************************************************
+#include <EfiBind.h>
+
+    .686p: 
+
+.globl ASM_PFX(mCode16Size)
+
+.data
+mCode16Size:    .long   _TEXT16SIZE
+
+.data
+
+NullSegSel:     .quad   0
+_16BitCsSel:    
+                .word   -1
+                .word   0
+                .byte   0
+                .byte   0x9b
+                .byte   0x8f            # 16-bit segment
+                .byte   0
+_16BitSsSel:
+                .word   -1
+                .word   0
+                .byte   0
+                .byte   0x93
+                .byte   0x8f           # 16-bit segment
+                .byte   0
+
+_16Gdtr:
+                .word      _16Gdtr - NullSegSel - 1
+                .long      NullSegSel
+
+
+.text
+.align  16
+
+
+ASM_PFX(Thunk16):
+    push   %ebp
+    push   %ebx
+    push   %esi
+    push   %edi
+    push   %ds
+    push   %es
+    push   %fs
+    push   %gs
+    mov    0x24(%esp),%esi
+    movzwl 0x32(%esi),%edx
+    mov    0xc(%esi),%edi
+    add    $0xffffffb0,%edi
+    push   %edi                       #; save stack offset
+    imul   $0x10,%edx,%eax            #; eax <- edx*16
+    add    %eax,%edi                  #; edi <- linear address of 16-bit stack
+    push   $0xd
+    pop    %ecx
+    rep movsl %ds:(%esi),%es:(%edi)   #; copy context to 16-bit stack
+    pop    %ebx                       #; ebx <- 16-bit stack offset
+    mov    $L_Label1,%eax
+    stos   %eax,%es:(%edi)
+    movl   %cs,%eax
+    stos   %ax,%es:(%edi)
+    mov    0x28(%esp),%eax
+    stos   %ax,%es:(%edi)
+    mov    %esp,%eax
+    stos   %eax,%es:(%edi)
+    movl   %ss,%eax
+    stos   %ax,%es:(%edi)
+    sgdtl  (%edi)
+    sidtl  0x24(%esp)
+    mov    %cr0,%esi
+    mov    %esi,0x6(%edi)             #; save CR0
+    and    $0x7ffffffe,%esi           #; esi <- CR0 to set
+    mov    %cr4,%eax
+    mov    %eax,0xa(%edi)             #; save CR4
+    and    $0xcf,%al                  #; clear PAE & PSE
+    mov    %edx,%edi                  #; edi <- 16-bit stack segment
+    mov    0x2c(%esp),%edx
+    shl    $0x10,%edx
+    push   %edx
+    pop    %edx
+    mov    $(_16BitSsSel - NullSegSel),%dx
+    lgdtl  _16Gdtr                    #bugbug mismatch.
+    .byte  0xea
+    .long  L_16Bit                    #bugbug mismatch.
+    .word  _16BitCsSel - NullSegSel
+L_16Bit:   
+    .byte  0x66 
+    movw   %dx,%ss
+    mov    %esi,%cr0
+    mov    %eax,%cr4
+    .byte  0x67
+    .byte  0xff
+    .byte  0x6c
+    .byte  0x24
+    .byte  0xfc
+    
+L_Lable1:
+    movl   %ss,%eax
+    shl    $0x4,%eax
+    add    %esp,%eax
+    lss    0x3c(%esp),%esp
+    lidtl  0x24(%esp)
+    pop    %gs
+    pop    %fs
+    pop    %es
+    pop    %ds
+    pop    %edi
+    pop    %esi
+    pop    %ebx
+    pop    %ebp
+    ret 
+
+.code16
+_Code16Addr:
+ASM_PFX(RealMode):
+    movw    %di, %ss                    # set up stack
+    movl    %ebx, %esp
+    lidt    %cs:_16Idtr - _Code16Addr  #lidt    fword ptr cs:[_16Idtr - _Code16Addr]
+    .byte   0x66
+    popaw
+    popw    %ds
+    popw    %es
+    popw    %fs
+    popw    %gs
+    addw    $4, %sp                     # skip EFlags
+    testw   $1, 14(%esp)                  #(_STK16 ptr [esp + 8]).ThunkFlags, 1
+    jz      1f
+    pushf
+1: 
+    pushw   %cs
+#    push    @FarCallRet - _Code16Addr
+    .byte   0x68                        # push /iw
+    .word   FarCallRet - _Code16Addr
+    jz      2f
+    ljmp    *6(%esp)                  #bugbug
+2: 
+    ljmp    *4(%esp)                  #bugbug
+FarCallRet: 
+    pushfl
+    pushw   %gs
+    pushw   %fs
+    pushw   %es
+    pushw   %ds
+    pushal
+    cli
+    .byte   0x66                        # sizeof (IA32_REGS) = 13 * 4 = 52
+    lgdt    66(%esp)                    #lgdt    (_STK16 ptr [esp + sizeof (IA32_REGS)]).SavedGdtr
+    mov     76(%esp), %eax
+    movl    %eax, %cr4
+    mov     72(%esp), %eax
+    movl    %eax, %cr0                   # restore CR0
+    ljmpl   *52(%esp)                    
+#RealMode ENDP
+
+.text
+_16Idtr:
+    .word 0x3ff                         #_16Idtr     FWORD   (1 SHL 10) - 1
+    .byte 0x00
+
+_TEXT16END: 
+
+_TEXT16SIZE = _TEXT16END - _Code16Addr
+
+
diff --git a/EdkCompatibilityPkg/Foundation/Library/Thunk16/Thunk16Lib_Edk2.inf b/EdkCompatibilityPkg/Foundation/Library/Thunk16/Thunk16Lib_Edk2.inf
index 7d894b6809..aef578e4cd 100644
--- a/EdkCompatibilityPkg/Foundation/Library/Thunk16/Thunk16Lib_Edk2.inf
+++ b/EdkCompatibilityPkg/Foundation/Library/Thunk16/Thunk16Lib_Edk2.inf
@@ -27,6 +27,7 @@ COMPONENT_TYPE       = LIBRARY
 [sources.ia32]
   Ia32/Thunk16.asm  | MSFT
   Ia32/Thunk16.asm  | INTEL 
+  Ia32/Thunk16.S    | GCC
   Ia32/Fx.asm       | MSFT
   Ia32/Fx.asm       | INTEL
   Ia32/Fx.S         | GCC