diff options
Diffstat (limited to 'src/VBox/Devices/EFI/Firmware/MdePkg/Library/BaseMemoryLibRepStr/X64/CopyMem.nasm')
| -rw-r--r-- | src/VBox/Devices/EFI/Firmware/MdePkg/Library/BaseMemoryLibRepStr/X64/CopyMem.nasm | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/src/VBox/Devices/EFI/Firmware/MdePkg/Library/BaseMemoryLibRepStr/X64/CopyMem.nasm b/src/VBox/Devices/EFI/Firmware/MdePkg/Library/BaseMemoryLibRepStr/X64/CopyMem.nasm new file mode 100644 index 00000000..aa579b2f --- /dev/null +++ b/src/VBox/Devices/EFI/Firmware/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 + |