Moved the MdePkg to OldMdePkg so that new code in MdePkg does not break existing...

[mirror_edk2.git] / OldMdePkg / Library / BaseMemoryLibRepStr / x64 / CopyMem.asm

diff --git a/OldMdePkg/Library/BaseMemoryLibRepStr/x64/CopyMem.asm b/OldMdePkg/Library/BaseMemoryLibRepStr/x64/CopyMem.asm
new file mode 100644 (file)
index 0000000..a2e0405
--- /dev/null
+++ b/OldMdePkg/Library/BaseMemoryLibRepStr/x64/CopyMem.asm
@@ -0,0 +1,61 @@
+;------------------------------------------------------------------------------\r
+;\r
+; Copyright (c) 2006, Intel Corporation\r
+; All rights reserved. This program and the accompanying materials\r
+; are licensed and made available under the terms and conditions of the BSD License\r
+; which accompanies this distribution.  The full text of the license may be found at\r
+; http://opensource.org/licenses/bsd-license.php\r
+;\r
+; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
+; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
+;\r
+; Module Name:\r
+;\r
+;   CopyMem.Asm\r
+;\r
+; Abstract:\r
+;\r
+;   CopyMem function\r
+;\r
+; Notes:\r
+;\r
+;------------------------------------------------------------------------------\r
+\r
+    .code\r
+\r
+;------------------------------------------------------------------------------\r
+;  VOID *\r
+;  EFIAPI\r
+;  InternalMemCopyMem (\r
+;    IN VOID   *Destination,\r
+;    IN VOID   *Source,\r
+;    IN UINTN  Count\r
+;    )\r
+;------------------------------------------------------------------------------\r
+InternalMemCopyMem  PROC    USES    rsi rdi\r
+    mov     rsi, rdx                    ; rsi <- Source\r
+    mov     rdi, rcx                    ; rdi <- Destination\r
+    lea     r9, [rsi + r8 - 1]          ; r9 <- End of Source\r
+    cmp     rsi, rdi\r
+    mov     rax, rdi                    ; rax <- Destination as return value\r
+    jae     @F\r
+    cmp     r9, rsi\r
+    jae     @CopyBackward               ; Copy backward if overlapped\r
+@@:\r
+    mov     rcx, r8\r
+    and     r8, 7\r
+    shr     rcx, 3\r
+    rep     movsq                       ; Copy as many Qwords as possible\r
+    jmp     @CopyBytes\r
+@CopyBackward:\r
+    mov     rsi, r9                     ; rsi <- End of Source\r
+    lea     rdi, [rdi + r8 - 1]         ; esi <- End of Destination\r
+    std                                 ; set direction flag\r
+@CopyBytes:\r
+    mov     rcx, r8\r
+    rep     movsb                       ; Copy bytes backward\r
+    cld\r
+    ret\r
+InternalMemCopyMem  ENDP\r
+\r
+    END\r