diff options
Diffstat (limited to 'MdePkg/Library/BaseMemoryLibRepStr/x64/CopyMem.asm')
-rw-r--r-- | MdePkg/Library/BaseMemoryLibRepStr/x64/CopyMem.asm | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/MdePkg/Library/BaseMemoryLibRepStr/x64/CopyMem.asm b/MdePkg/Library/BaseMemoryLibRepStr/x64/CopyMem.asm new file mode 100644 index 0000000000..43630715cb --- /dev/null +++ b/MdePkg/Library/BaseMemoryLibRepStr/x64/CopyMem.asm @@ -0,0 +1,52 @@ +;------------------------------------------------------------------------------
+;
+; Copyright (c) 2006, 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:
+;
+; CopyMem.Asm
+;
+; Abstract:
+;
+; CopyMem function
+;
+; Notes:
+;
+;------------------------------------------------------------------------------
+
+ .code
+
+InternalMemCopyMem PROC USES rsi rdi
+ mov rsi, rdx ; rsi <- Source
+ mov rdi, rcx ; rdi <- Destination
+ lea r9, [rdi + r8 - 1] ; r9 <- End of Destination
+ cmp rsi, rdi
+ mov rax, rdi ; rax <- Destination as return value
+ jae @F
+ cmp r9, rsi
+ jae @CopyBackward ; Copy backward if overlapped
+@@:
+ mov rcx, r8
+ and r8, 7
+ shr rcx, 3
+ rep movsq ; Copy as many Qwords as possible
+ jmp @CopyBytes
+@CopyBackward:
+ mov rdi, r9 ; rdi <- End of Destination
+ lea rsi, [rsi + r8 - 1] ; esi <- End of Source
+ std ; set direction flag
+@CopyBytes:
+ mov rcx, r8
+ rep movsb ; Copy bytes backward
+ cld
+ ret
+InternalMemCopyMem ENDP
+
+ END
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