diff options
| author |   Angelos Mouzakitis <a.mouzakitis@virtualopensystems.com> | 2023-10-10 14:33:42 +0000 |
|---|---|---|
| committer | Angelos Mouzakitis <a.mouzakitis@virtualopensystems.com> | 2023-10-10 14:33:42 +0000 |
| commit | af1a266670d040d2f4083ff309d732d648afba2a (patch) | |
| tree | 2fc46203448ddcc6f81546d379abfaeb323575e9 /roms/edk2/MdePkg/Library/BaseMemoryLibRepStr/X64/CopyMem.nasm | |
| parent | e02cda008591317b1625707ff8e115a4841aa889 (diff) | |
Change-Id: Iaf8d18082d3991dec7c0ebbea540f092188eb4ec
Diffstat (limited to 'roms/edk2/MdePkg/Library/BaseMemoryLibRepStr/X64/CopyMem.nasm')
| -rw-r--r-- | roms/edk2/MdePkg/Library/BaseMemoryLibRepStr/X64/CopyMem.nasm | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/roms/edk2/MdePkg/Library/BaseMemoryLibRepStr/X64/CopyMem.nasm b/roms/edk2/MdePkg/Library/BaseMemoryLibRepStr/X64/CopyMem.nasm new file mode 100644 index 000000000..c29dab6cd --- /dev/null +++ b/roms/edk2/MdePkg/Library/BaseMemoryLibRepStr/X64/CopyMem.nasm @@ -0,0 +1,59 @@ +;------------------------------------------------------------------------------
+;
+; Copyright (c) 2006, Intel Corporation. All rights reserved.<BR>
+; SPDX-License-Identifier: BSD-2-Clause-Patent
+;
+; Module Name:
+;
+; CopyMem.Asm
+;
+; Abstract:
+;
+; CopyMem function
+;
+; Notes:
+;
+;------------------------------------------------------------------------------
+
+ DEFAULT REL
+ SECTION .text
+
+;------------------------------------------------------------------------------
+; VOID *
+; EFIAPI
+; InternalMemCopyMem (
+; IN VOID *Destination,
+; IN VOID *Source,
+; IN UINTN Count
+; )
+;------------------------------------------------------------------------------
+global ASM_PFX(InternalMemCopyMem)
+ASM_PFX(InternalMemCopyMem):
+ push rsi
+ push rdi
+ mov rsi, rdx ; rsi <- Source
+ mov rdi, rcx ; rdi <- Destination
+ lea r9, [rsi + r8 - 1] ; r9 <- End of Source
+ cmp rsi, rdi
+ mov rax, rdi ; rax <- Destination as return value
+ jae .0
+ cmp r9, rdi
+ jae @CopyBackward ; Copy backward if overlapped
+.0:
+ mov rcx, r8
+ and r8, 7
+ shr rcx, 3
+ rep movsq ; Copy as many Qwords as possible
+ jmp @CopyBytes
+@CopyBackward:
+ mov rsi, r9 ; rsi <- End of Source
+ lea rdi, [rdi + r8 - 1] ; esi <- End of Destination
+ std ; set direction flag
+@CopyBytes:
+ mov rcx, r8
+ rep movsb ; Copy bytes backward
+ cld
+ pop rdi
+ pop rsi
+ ret
+
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