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	Contributed-under: TianoCore Contribution Agreement 1.0 Signed off by: Ravi Rangarajan <ravi.p.rangarajan@intel.com> Reviewed by: Maurice Ma <maurice.ma@intel.com> Reviewed by: Jiewen Yao <jiewen.yao@intel.com> Reviewed by: Giri Mudusuru <giri.p.mudusuru@intel.com> Reviewed by: Liming Gao <liming.gao@intel.com> git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@15705 6f19259b-4bc3-4df7-8a09-765794883524
		
			
				
	
	
		
			83 lines
		
	
	
		
			2.5 KiB
		
	
	
	
		
			NASM
		
	
	
	
	
	
			
		
		
	
	
			83 lines
		
	
	
		
			2.5 KiB
		
	
	
	
		
			NASM
		
	
	
	
	
	
;------------------------------------------------------------------------------
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;
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; Copyright (c) 2014, Intel Corporation. All rights reserved.<BR>
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; This program and the accompanying materials
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; are licensed and made available under the terms and conditions of the BSD License
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; which accompanies this distribution.  The full text of the license may be found at
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; http://opensource.org/licenses/bsd-license.php.
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;
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; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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;
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; Abstract:
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;
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;   Switch the stack from temporary memory to permenent memory.
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;
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;------------------------------------------------------------------------------
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    .586p
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    .model  flat,C
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    .code
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;------------------------------------------------------------------------------
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; VOID
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; EFIAPI
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; SecSwitchStack (
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;   UINT32   TemporaryMemoryBase,
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;   UINT32   PermenentMemoryBase
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;   );
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;------------------------------------------------------------------------------
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SecSwitchStack   PROC
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    ;
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    ; Save three register: eax, ebx, ecx
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    ;
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    push  eax
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    push  ebx
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    push  ecx
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    push  edx
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    ;
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    ; !!CAUTION!! this function address's is pushed into stack after
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    ; migration of whole temporary memory, so need save it to permenent
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    ; memory at first!
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    ;
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    mov   ebx, [esp + 20]          ; Save the first parameter
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    mov   ecx, [esp + 24]          ; Save the second parameter
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    ;
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    ; Save this function's return address into permenent memory at first.
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    ; Then, Fixup the esp point to permenent memory
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    ;
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    mov   eax, esp
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    sub   eax, ebx
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    add   eax, ecx
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    mov   edx, dword ptr [esp]         ; copy pushed register's value to permenent memory
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    mov   dword ptr [eax], edx
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    mov   edx, dword ptr [esp + 4]
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    mov   dword ptr [eax + 4], edx
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    mov   edx, dword ptr [esp + 8]
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    mov   dword ptr [eax + 8], edx
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    mov   edx, dword ptr [esp + 12]
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    mov   dword ptr [eax + 12], edx
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    mov   edx, dword ptr [esp + 16]    ; Update this function's return address into permenent memory
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    mov   dword ptr [eax + 16], edx
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    mov   esp, eax                     ; From now, esp is pointed to permenent memory
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    ;
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    ; Fixup the ebp point to permenent memory
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    ;
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    mov   eax, ebp
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    sub   eax, ebx
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    add   eax, ecx
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    mov   ebp, eax                ; From now, ebp is pointed to permenent memory
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    pop   edx
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    pop   ecx
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    pop   ebx
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    pop   eax
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    ret
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SecSwitchStack   ENDP
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    END
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