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			62 lines
		
	
	
		
			2.0 KiB
		
	
	
	
		
			NASM
		
	
	
	
	
	
			
		
		
	
	
			62 lines
		
	
	
		
			2.0 KiB
		
	
	
	
		
			NASM
		
	
	
	
	
	
| ;------------------------------------------------------------------------------
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| ;
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| ; Copyright (c) 2006, 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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| ; Module Name:
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| ;
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| ;   CopyMem.Asm
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| ;
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| ; Abstract:
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| ;
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| ;   CopyMem function
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| ;
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| ; Notes:
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| ;
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| ;------------------------------------------------------------------------------
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| 
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|     .code
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| 
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| ;------------------------------------------------------------------------------
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| ;  VOID *
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| ;  EFIAPI
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| ;  InternalMemCopyMem (
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| ;    IN VOID   *Destination,
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| ;    IN VOID   *Source,
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| ;    IN UINTN  Count
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| ;    )
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| ;------------------------------------------------------------------------------
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| InternalMemCopyMem  PROC    USES    rsi rdi
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|     mov     rsi, rdx                    ; rsi <- Source
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|     mov     rdi, rcx                    ; rdi <- Destination
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|     lea     r9, [rsi + r8 - 1]          ; r9 <- End of Source
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|     cmp     rsi, rdi
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|     mov     rax, rdi                    ; rax <- Destination as return value
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|     jae     @F
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|     cmp     r9, rdi
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|     jae     @CopyBackward               ; Copy backward if overlapped
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| @@:
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|     mov     rcx, r8
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|     and     r8, 7
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|     shr     rcx, 3
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|     rep     movsq                       ; Copy as many Qwords as possible
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|     jmp     @CopyBytes
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| @CopyBackward:
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|     mov     rsi, r9                     ; rsi <- End of Source
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|     lea     rdi, [rdi + r8 - 1]         ; esi <- End of Destination
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|     std                                 ; set direction flag
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| @CopyBytes:
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|     mov     rcx, r8
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|     rep     movsb                       ; Copy bytes backward
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|     cld
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|     ret
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| InternalMemCopyMem  ENDP
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| 
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|     END
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